diff --git a/packages/core/src/Serialization/Certificates/PoolParams/PoolParams.ts b/packages/core/src/Serialization/Certificates/PoolParams/PoolParams.ts
index dc84c5c7629..0a65c32166d 100644
--- a/packages/core/src/Serialization/Certificates/PoolParams/PoolParams.ts
+++ b/packages/core/src/Serialization/Certificates/PoolParams/PoolParams.ts
@@ -2,11 +2,13 @@
 import * as Cardano from '../../../Cardano';
 import * as Crypto from '@cardano-sdk/crypto';
 import { CborReader, CborReaderState, CborWriter } from '../../CBOR';
+import { CborSet, Hash } from '../../Common';
 import { HexBlob, InvalidArgumentError } from '@cardano-sdk/util';
 import { PoolMetadata } from './PoolMetadata';
 import { Relay } from './Relay';
 import { UnitInterval } from '../../Common/UnitInterval';
 
+type PoolOwners = CborSet<Crypto.Ed25519KeyHashHex, Hash<Crypto.Ed25519KeyHashHex>>;
 /**
  * Stake pool update certificate parameters.
  *
@@ -20,7 +22,7 @@ export class PoolParams {
   #cost: Cardano.Lovelace;
   #margin: UnitInterval;
   #rewardAccount: Cardano.RewardAddress;
-  #poolOwners: Array<Crypto.Ed25519KeyHashHex>;
+  #poolOwners: PoolOwners;
   #relays: Array<Relay>;
   #poolMetadata?: PoolMetadata;
   #originalBytes: HexBlob | undefined = undefined;
@@ -47,7 +49,7 @@ export class PoolParams {
     cost: Cardano.Lovelace,
     margin: UnitInterval,
     rewardAccount: Cardano.RewardAddress,
-    poolOwners: Array<Crypto.Ed25519KeyHashHex>,
+    poolOwners: PoolOwners,
     relays: Array<Relay>,
     poolMetadata?: PoolMetadata
   ) {
@@ -93,7 +95,7 @@ export class PoolParams {
    * An example is the PoolRegistration certificate which flattens the pool parameters in the pool_registration, rather
    * than insert as a subgroup
    *
-   * @param the parent writer that already created the subgroup
+   * @param writer the parent writer that already created the subgroup
    * @returns The PoolMetadata in CBOR format.
    */
   toFlattenedCbor(writer: CborWriter): HexBlob {
@@ -103,10 +105,7 @@ export class PoolParams {
     writer.writeInt(this.#cost);
     writer.writeEncodedValue(Buffer.from(this.#margin.toCbor(), 'hex'));
     writer.writeByteString(Buffer.from(this.#rewardAccount.toAddress().toBytes(), 'hex'));
-
-    writer.writeStartArray(this.#poolOwners.length);
-    for (const owner of this.#poolOwners) writer.writeByteString(Buffer.from(owner, 'hex'));
-
+    writer.writeEncodedValue(Buffer.from(this.#poolOwners.toCbor(), 'hex'));
     writer.writeStartArray(this.#relays.length);
     for (const relay of this.#relays) writer.writeEncodedValue(Buffer.from(relay.toCbor(), 'hex'));
 
@@ -158,17 +157,14 @@ export class PoolParams {
     const cost = reader.readInt();
     const margin = UnitInterval.fromCbor(HexBlob.fromBytes(reader.readEncodedValue()));
     const rewardAccount = Cardano.Address.fromBytes(HexBlob.fromBytes(reader.readByteString())).asReward()!;
-    const poolOwner = new Array<Crypto.Ed25519KeyHashHex>();
     const relays = new Array<Relay>();
     let poolMetadata;
 
     // Pool owners.
-    reader.readStartArray();
-
-    while (reader.peekState() !== CborReaderState.EndArray)
-      poolOwner.push(Crypto.Ed25519KeyHashHex(HexBlob.fromBytes(reader.readByteString())));
-
-    reader.readEndArray();
+    const poolOwner = CborSet.fromCbor<Crypto.Ed25519KeyHashHex, Hash<Crypto.Ed25519KeyHashHex>>(
+      HexBlob.fromBytes(reader.readEncodedValue()),
+      Hash.fromCbor
+    );
 
     // Relays
     reader.readStartArray();
@@ -200,9 +196,9 @@ export class PoolParams {
       id: Cardano.PoolId.fromKeyHash(this.#operator),
       margin: this.#margin.toCore(),
       metadataJson: this.#poolMetadata?.toCore(),
-      owners: this.#poolOwners.map((keyHash) =>
-        Cardano.createRewardAccount(keyHash, rewardAccountAddress.getNetworkId())
-      ),
+      owners: this.#poolOwners
+        .toCore()
+        .map((keyHash) => Cardano.createRewardAccount(keyHash, rewardAccountAddress.getNetworkId())),
       pledge: this.#pledge,
       relays: this.#relays.map((relay) => relay.toCore()),
       rewardAccount: this.#rewardAccount.toAddress().toBech32() as Cardano.RewardAccount,
@@ -223,8 +219,11 @@ export class PoolParams {
       params.cost,
       UnitInterval.fromCore(params.margin),
       Cardano.Address.fromBech32(params.rewardAccount).asReward()!,
-      params.owners.map((owner) =>
-        Crypto.Ed25519KeyHashHex(Cardano.Address.fromBech32(owner).asReward()!.getPaymentCredential()!.hash)
+      CborSet.fromCore(
+        params.owners.map((owner) =>
+          Crypto.Ed25519KeyHashHex(Cardano.Address.fromBech32(owner).asReward()!.getPaymentCredential()!.hash)
+        ),
+        Hash.fromCore
       ),
       params.relays.map((relay) => Relay.fromCore(relay)),
       params.metadataJson ? PoolMetadata.fromCore(params.metadataJson) : undefined
@@ -356,7 +355,7 @@ export class PoolParams {
    *
    * @returns The pool owners key hashes.
    */
-  poolOwners(): Array<Crypto.Ed25519KeyHashHex> {
+  poolOwners(): PoolOwners {
     return this.#poolOwners;
   }
 
@@ -365,8 +364,8 @@ export class PoolParams {
    *
    * @param poolOwners The pool owners key hashes.
    */
-  setPoolOwners(poolOwners: Array<Crypto.Ed25519KeyHashHex>): void {
-    this.#poolOwners = [...poolOwners];
+  setPoolOwners(poolOwners: PoolOwners): void {
+    this.#poolOwners = poolOwners;
     this.#originalBytes = undefined;
   }
 
diff --git a/packages/core/src/Serialization/Common/Credential.ts b/packages/core/src/Serialization/Common/Credential.ts
new file mode 100644
index 00000000000..5f4d6bd9dbf
--- /dev/null
+++ b/packages/core/src/Serialization/Common/Credential.ts
@@ -0,0 +1,50 @@
+import { Cardano } from '../..';
+import { CborReader, CborWriter } from '../CBOR';
+import { Hash28ByteBase16 } from '@cardano-sdk/crypto';
+import { HexBlob, InvalidArgumentError } from '@cardano-sdk/util';
+import { hexToBytes } from '../../util/misc';
+
+const CREDENTIAL_ARRAY_SIZE = 2;
+
+export class Credential {
+  #value: Cardano.Credential;
+
+  private constructor(value: Cardano.Credential) {
+    this.#value = value;
+  }
+
+  toCbor() {
+    const writer = new CborWriter();
+    writer.writeStartArray(CREDENTIAL_ARRAY_SIZE);
+    writer.writeInt(this.#value.type);
+    writer.writeByteString(hexToBytes(this.#value.hash as unknown as HexBlob));
+    return writer.encodeAsHex();
+  }
+
+  static fromCbor(cbor: HexBlob): Credential {
+    const reader = new CborReader(cbor);
+    if (reader.readStartArray() !== CREDENTIAL_ARRAY_SIZE)
+      throw new InvalidArgumentError(
+        'cbor',
+        `Expected an array of ${CREDENTIAL_ARRAY_SIZE} elements, but got an array of ${length} elements`
+      );
+
+    const type = Number(reader.readUInt());
+    const hash = HexBlob.fromBytes(reader.readByteString()) as unknown as Hash28ByteBase16;
+
+    reader.readEndArray();
+    return new Credential({ hash, type });
+  }
+
+  toCore(): Cardano.Credential {
+    return { ...this.#value };
+  }
+
+  static fromCore(credential: Cardano.Credential): Credential {
+    return new Credential({ ...credential });
+  }
+
+  value() {
+    return { ...this.#value };
+  }
+}
diff --git a/packages/core/src/Serialization/Common/Hash.ts b/packages/core/src/Serialization/Common/Hash.ts
new file mode 100644
index 00000000000..d6e232c00b8
--- /dev/null
+++ b/packages/core/src/Serialization/Common/Hash.ts
@@ -0,0 +1,33 @@
+import { CborReader, CborWriter } from '../CBOR';
+import { HexBlob } from '@cardano-sdk/util';
+
+export class Hash<T extends string> {
+  #value: T;
+
+  constructor(value: T) {
+    this.#value = value;
+  }
+
+  toCbor() {
+    const writer = new CborWriter();
+    writer.writeByteString(Buffer.from(this.#value, 'hex'));
+    return writer.encodeAsHex();
+  }
+
+  static fromCbor<T extends string>(cbor: HexBlob): Hash<T> {
+    const reader = new CborReader(cbor);
+    return new Hash<T>(HexBlob.fromBytes(reader.readByteString()) as unknown as T);
+  }
+
+  toCore() {
+    return this.#value;
+  }
+
+  static fromCore<T extends string>(hash: T): Hash<T> {
+    return new Hash<T>(hash);
+  }
+
+  value() {
+    return this.#value;
+  }
+}
diff --git a/packages/core/src/Serialization/Common/index.ts b/packages/core/src/Serialization/Common/index.ts
index 541187c3278..0f5b47809c4 100644
--- a/packages/core/src/Serialization/Common/index.ts
+++ b/packages/core/src/Serialization/Common/index.ts
@@ -5,3 +5,5 @@ export * from './Datum';
 export * from './Anchor';
 export * from './GovernanceActionId';
 export * from './CborSet';
+export * from './Hash';
+export * from './Credential';
diff --git a/packages/core/src/Serialization/TransactionBody/ProposalProcedure/UpdateCommittee.ts b/packages/core/src/Serialization/TransactionBody/ProposalProcedure/UpdateCommittee.ts
index df3dc21f081..51cd40aed74 100644
--- a/packages/core/src/Serialization/TransactionBody/ProposalProcedure/UpdateCommittee.ts
+++ b/packages/core/src/Serialization/TransactionBody/ProposalProcedure/UpdateCommittee.ts
@@ -1,12 +1,12 @@
 /* eslint-disable max-statements */
 import * as Cardano from '../../../Cardano';
 import { CborReader, CborReaderState, CborWriter } from '../../CBOR';
-import { CommitteeMember, Credential, GovernanceActionType } from '../../../Cardano';
+import { CborSet, Credential, UnitInterval } from '../../Common';
+import { CommitteeMember, GovernanceActionType } from '../../../Cardano';
 import { GovernanceActionId } from '../../Common/GovernanceActionId';
 import { GovernanceActionKind } from './GovernanceActionKind';
 import { Hash28ByteBase16 } from '@cardano-sdk/crypto';
 import { HexBlob, InvalidArgumentError } from '@cardano-sdk/util';
-import { UnitInterval } from '../../Common';
 import { hexToBytes } from '../../../util/misc';
 
 const EMBEDDED_GROUP_SIZE = 5;
@@ -14,10 +14,12 @@ const CREDENTIAL_ARRAY_SIZE = 2;
 const CREDENTIAL_INDEX = 0;
 const EPOCH_INDEX = 1;
 
+type CredentialSet = CborSet<ReturnType<Credential['toCore']>, Credential>;
+
 /** Modifies the composition of the constitutional committee, its signature threshold, or its terms of operation. */
 export class UpdateCommittee {
   #govActionId: GovernanceActionId | undefined;
-  #membersToBeRemoved: Cardano.Credential[];
+  #membersToBeRemoved: CredentialSet;
   #membersToBeAdded: [Cardano.Credential, number][];
   #newQuorum: UnitInterval;
   #originalBytes: HexBlob | undefined = undefined;
@@ -31,7 +33,7 @@ export class UpdateCommittee {
    * @param govActionId Previous governance action id of `UpdateCommittee`.
    */
   constructor(
-    membersToBeRemoved: Cardano.Credential[],
+    membersToBeRemoved: CredentialSet,
     membersToBeAdded: [Cardano.Credential, number][],
     newQuorum: UnitInterval,
     govActionId?: GovernanceActionId
@@ -58,12 +60,7 @@ export class UpdateCommittee {
     writer.writeInt(GovernanceActionKind.UpdateCommittee);
     this.#govActionId ? writer.writeEncodedValue(hexToBytes(this.#govActionId.toCbor())) : writer.writeNull();
 
-    writer.writeStartArray(this.#membersToBeRemoved.length);
-    for (const entry of this.#membersToBeRemoved) {
-      writer.writeStartArray(CREDENTIAL_ARRAY_SIZE);
-      writer.writeInt(entry.type);
-      writer.writeByteString(hexToBytes(entry.hash as unknown as HexBlob));
-    }
+    writer.writeEncodedValue(hexToBytes(this.#membersToBeRemoved.toCbor()));
 
     writer.writeStartMap(this.#membersToBeAdded.length);
     for (const entry of this.#membersToBeAdded) {
@@ -111,24 +108,10 @@ export class UpdateCommittee {
       govActionId = GovernanceActionId.fromCbor(HexBlob.fromBytes(reader.readEncodedValue()));
     }
 
-    reader.readStartArray();
-
-    const membersToRemove: Cardano.Credential[] = [];
-    while (reader.peekState() !== CborReaderState.EndArray) {
-      if (reader.readStartArray() !== CREDENTIAL_ARRAY_SIZE)
-        throw new InvalidArgumentError(
-          'cbor',
-          `Expected an array of ${CREDENTIAL_ARRAY_SIZE} elements, but got an array of ${length} elements`
-        );
-
-      const type = Number(reader.readUInt());
-      const hash = HexBlob.fromBytes(reader.readByteString()) as unknown as Hash28ByteBase16;
-
-      reader.readEndArray();
-      membersToRemove.push({ hash, type });
-    }
-
-    reader.readEndArray();
+    const membersToRemove: CredentialSet = CborSet.fromCbor(
+      HexBlob.fromBytes(reader.readEncodedValue()),
+      Credential.fromCbor
+    );
 
     reader.readStartMap();
 
@@ -173,7 +156,7 @@ export class UpdateCommittee {
           epoch: Cardano.EpochNo(entry[EPOCH_INDEX])
         }))
       ),
-      membersToBeRemoved: new Set<Credential>(this.#membersToBeRemoved),
+      membersToBeRemoved: new Set<Cardano.Credential>(this.#membersToBeRemoved.toCore()),
       newQuorumThreshold: this.#newQuorum.toCore()
     };
   }
@@ -185,7 +168,7 @@ export class UpdateCommittee {
    */
   static fromCore(updateCommittee: Cardano.UpdateCommittee) {
     return new UpdateCommittee(
-      [...updateCommittee.membersToBeRemoved],
+      CborSet.fromCore([...updateCommittee.membersToBeRemoved], Credential.fromCore),
       [...updateCommittee.membersToBeAdded].map((entry) => [entry.coldCredential, entry.epoch]),
       UnitInterval.fromCore(updateCommittee.newQuorumThreshold),
       updateCommittee.governanceActionId !== null
@@ -209,7 +192,7 @@ export class UpdateCommittee {
    * @returns the committee members to be removed.
    */
   membersToBeRemoved(): Cardano.Credential[] {
-    return this.#membersToBeRemoved;
+    return this.#membersToBeRemoved.toCore();
   }
 
   /**
diff --git a/packages/core/src/Serialization/TransactionBody/TransactionBody.ts b/packages/core/src/Serialization/TransactionBody/TransactionBody.ts
index 7f71ea969ff..7d625ca9106 100644
--- a/packages/core/src/Serialization/TransactionBody/TransactionBody.ts
+++ b/packages/core/src/Serialization/TransactionBody/TransactionBody.ts
@@ -2,6 +2,7 @@
 import * as Cardano from '../../Cardano';
 import * as Crypto from '@cardano-sdk/crypto';
 import { CborReader, CborReaderState, CborWriter } from '../CBOR';
+import { CborSet, Hash } from '../Common';
 import { Certificate } from '../Certificates';
 import { HexBlob } from '@cardano-sdk/util';
 import { ProposalProcedure } from './ProposalProcedure';
@@ -10,32 +11,35 @@ import { TransactionInput } from './TransactionInput';
 import { TransactionOutput } from './TransactionOutput';
 import { Update } from '../Update';
 import { VotingProcedures } from './VotingProcedures';
+import { hexToBytes } from '../../util/misc';
 import { multiAssetsToTokenMap, sortCanonically, tokenMapToMultiAsset } from './Utils';
 
+type TransactionInputSet = CborSet<ReturnType<TransactionInput['toCore']>, TransactionInput>;
+
 /** The transaction body encapsulates the core details of a transaction. */
 export class TransactionBody {
   // Required fields
-  #inputs: Array<TransactionInput>;
+  #inputs: TransactionInputSet;
   #outputs: Array<TransactionOutput>;
   #fee: Cardano.Lovelace;
 
   // Optional fields
   #ttl: Cardano.Slot | undefined;
-  #certs: Array<Certificate> | undefined;
+  #certs: CborSet<ReturnType<Certificate['toCore']>, Certificate> | undefined;
   #withdrawals: Map<Cardano.RewardAccount, Cardano.Lovelace> | undefined;
   #update: Update | undefined;
   #auxiliaryDataHash: Crypto.Hash32ByteBase16 | undefined;
   #validityStartInterval: Cardano.Slot | undefined;
   #mint: Cardano.TokenMap | undefined;
   #scriptDataHash: Crypto.Hash32ByteBase16 | undefined;
-  #collateral: Array<TransactionInput> | undefined;
-  #requiredSigners: Array<Crypto.Ed25519KeyHashHex> | undefined;
+  #collateral: TransactionInputSet | undefined;
+  #requiredSigners: CborSet<Crypto.Ed25519KeyHashHex, Hash<Crypto.Ed25519KeyHashHex>> | undefined;
   #networkId: Cardano.NetworkId | undefined;
   #collateralReturn: TransactionOutput | undefined;
   #totalCollateral: Cardano.Lovelace | undefined;
-  #referenceInputs: Array<TransactionInput> | undefined;
+  #referenceInputs: TransactionInputSet | undefined;
   #votingProcedures: VotingProcedures | undefined;
-  #proposalProcedures: Array<ProposalProcedure> | undefined;
+  #proposalProcedures: CborSet<ReturnType<ProposalProcedure['toCore']>, ProposalProcedure> | undefined;
   #currentTreasuryValue: Cardano.Lovelace | undefined;
   #donation: Cardano.Lovelace | undefined;
   #originalBytes: HexBlob | undefined = undefined;
@@ -49,7 +53,7 @@ export class TransactionBody {
    * @param ttl Specifies the slot number until which the transaction is valid. If the transaction isn't included in a block by this slot, it becomes invalid.
    */
   constructor(
-    inputs: Array<TransactionInput>,
+    inputs: TransactionInputSet,
     outputs: Array<TransactionOutput>,
     fee: Cardano.Lovelace,
     ttl?: Cardano.Slot
@@ -95,13 +99,9 @@ export class TransactionBody {
     //   }
     writer.writeStartMap(this.#getMapSize());
 
-    if (this.#inputs && this.#inputs.length > 0) {
+    if (this.#inputs && this.#inputs.size() > 0) {
       writer.writeInt(0n);
-      writer.writeStartArray(this.#inputs.length);
-
-      for (const input of this.#inputs) {
-        writer.writeEncodedValue(Buffer.from(input.toCbor(), 'hex'));
-      }
+      writer.writeEncodedValue(hexToBytes(this.#inputs.toCbor()));
     }
 
     if (this.#outputs && this.#outputs.length > 0) {
@@ -121,13 +121,9 @@ export class TransactionBody {
       writer.writeInt(this.#ttl);
     }
 
-    if (this.#certs && this.#certs.length > 0) {
+    if (this.#certs && this.#certs.size() > 0) {
       writer.writeInt(4n);
-      writer.writeStartArray(this.#certs.length);
-
-      for (const cert of this.#certs) {
-        writer.writeEncodedValue(Buffer.from(cert.toCbor(), 'hex'));
-      }
+      writer.writeEncodedValue(hexToBytes(this.#certs.toCbor()));
     }
 
     if (this.#withdrawals && this.#withdrawals.size > 0) {
@@ -195,24 +191,14 @@ export class TransactionBody {
       writer.writeByteString(Buffer.from(this.#scriptDataHash, 'hex'));
     }
 
-    if (this.#collateral && this.#collateral.length > 0) {
+    if (this.#collateral && this.#collateral.size() > 0) {
       writer.writeInt(13n);
-
-      writer.writeStartArray(this.#collateral.length);
-
-      for (const input of this.#collateral) {
-        writer.writeEncodedValue(Buffer.from(input.toCbor(), 'hex'));
-      }
+      writer.writeEncodedValue(hexToBytes(this.#collateral.toCbor()));
     }
 
-    if (this.#requiredSigners && this.#requiredSigners.length > 0) {
+    if (this.#requiredSigners && this.#requiredSigners.size() > 0) {
       writer.writeInt(14n);
-
-      writer.writeStartArray(this.#requiredSigners.length);
-
-      for (const signer of this.#requiredSigners) {
-        writer.writeByteString(Buffer.from(signer, 'hex'));
-      }
+      writer.writeEncodedValue(hexToBytes(this.#requiredSigners.toCbor()));
     }
 
     if (this.#networkId) {
@@ -230,14 +216,9 @@ export class TransactionBody {
       writer.writeInt(this.#totalCollateral);
     }
 
-    if (this.#referenceInputs && this.#referenceInputs.length > 0) {
+    if (this.#referenceInputs && this.#referenceInputs.size() > 0) {
       writer.writeInt(18n);
-
-      writer.writeStartArray(this.#referenceInputs.length);
-
-      for (const input of this.#referenceInputs) {
-        writer.writeEncodedValue(Buffer.from(input.toCbor(), 'hex'));
-      }
+      writer.writeEncodedValue(hexToBytes(this.#referenceInputs.toCbor()));
     }
 
     if (this.#votingProcedures) {
@@ -245,13 +226,9 @@ export class TransactionBody {
       writer.writeEncodedValue(Buffer.from(this.#votingProcedures.toCbor(), 'hex'));
     }
 
-    if (this.#proposalProcedures && this.#proposalProcedures.length > 0) {
+    if (this.#proposalProcedures && this.#proposalProcedures.size() > 0) {
       writer.writeInt(20n);
-      writer.writeStartArray(this.#proposalProcedures.length);
-
-      for (const procedure of this.#proposalProcedures) {
-        writer.writeEncodedValue(Buffer.from(procedure.toCbor(), 'hex'));
-      }
+      writer.writeEncodedValue(hexToBytes(this.#proposalProcedures.toCbor()));
     }
 
     if (this.#currentTreasuryValue) {
@@ -276,7 +253,7 @@ export class TransactionBody {
   static fromCbor(cbor: HexBlob): TransactionBody {
     const reader = new CborReader(cbor);
 
-    const inputs: Array<TransactionInput> = new Array<TransactionInput>();
+    const inputs = CborSet.fromCore([], TransactionInput.fromCore);
     const outputs: Array<TransactionOutput> = new Array<TransactionOutput>();
     const fee: Cardano.Lovelace = 0n;
     const body = new TransactionBody(inputs, outputs, fee);
@@ -288,14 +265,8 @@ export class TransactionBody {
 
       switch (key) {
         case 0n: {
-          reader.readStartArray();
-
-          while (reader.peekState() !== CborReaderState.EndArray) {
-            body.inputs().push(TransactionInput.fromCbor(HexBlob.fromBytes(reader.readEncodedValue())));
-          }
-
-          reader.readEndArray();
-
+          const inputsBytes = reader.readEncodedValue();
+          body.setInputs(CborSet.fromCbor(HexBlob.fromBytes(inputsBytes), TransactionInput.fromCbor));
           break;
         }
         case 1n: {
@@ -316,14 +287,7 @@ export class TransactionBody {
           body.setTtl(Cardano.Slot(Number(reader.readInt())));
           break;
         case 4n: {
-          reader.readStartArray();
-
-          body.setCerts(new Array<Certificate>());
-          while (reader.peekState() !== CborReaderState.EndArray) {
-            body.certs()!.push(Certificate.fromCbor(HexBlob.fromBytes(reader.readEncodedValue())));
-          }
-
-          reader.readEndArray();
+          body.setCerts(CborSet.fromCbor(HexBlob.fromBytes(reader.readEncodedValue()), Certificate.fromCbor));
           break;
         }
         case 5n: {
@@ -379,26 +343,15 @@ export class TransactionBody {
           body.setScriptDataHash(HexBlob.fromBytes(reader.readByteString()) as unknown as Crypto.Hash32ByteBase16);
           break;
         case 13n:
-          body.setCollateral(new Array<TransactionInput>());
-          reader.readStartArray();
-
-          while (reader.peekState() !== CborReaderState.EndArray) {
-            body.collateral()!.push(TransactionInput.fromCbor(HexBlob.fromBytes(reader.readEncodedValue())));
-          }
-
-          reader.readEndArray();
+          body.setCollateral(CborSet.fromCbor(HexBlob.fromBytes(reader.readEncodedValue()), TransactionInput.fromCbor));
           break;
         case 14n:
-          body.setRequiredSigners(new Array<Crypto.Ed25519KeyHashHex>());
-          reader.readStartArray();
-
-          while (reader.peekState() !== CborReaderState.EndArray) {
-            body
-              .requiredSigners()!
-              .push(HexBlob.fromBytes(reader.readByteString()) as unknown as Crypto.Ed25519KeyHashHex);
-          }
-
-          reader.readEndArray();
+          body.setRequiredSigners(
+            CborSet.fromCbor<Crypto.Ed25519KeyHashHex, Hash<Crypto.Ed25519KeyHashHex>>(
+              HexBlob.fromBytes(reader.readEncodedValue()),
+              Hash.fromCbor
+            )
+          );
           break;
         case 15n:
           body.setNetworkId(Number(reader.readInt()) as Cardano.NetworkId);
@@ -410,27 +363,17 @@ export class TransactionBody {
           body.setTotalCollateral(reader.readInt());
           break;
         case 18n:
-          body.setReferenceInputs(new Array<TransactionInput>());
-          reader.readStartArray();
-
-          while (reader.peekState() !== CborReaderState.EndArray) {
-            body.referenceInputs()!.push(TransactionInput.fromCbor(HexBlob.fromBytes(reader.readEncodedValue())));
-          }
-
-          reader.readEndArray();
+          body.setReferenceInputs(
+            CborSet.fromCbor(HexBlob.fromBytes(reader.readEncodedValue()), TransactionInput.fromCbor)
+          );
           break;
         case 19n:
           body.setVotingProcedures(VotingProcedures.fromCbor(HexBlob.fromBytes(reader.readEncodedValue())));
           break;
         case 20n:
-          body.setProposalProcedures(new Array<ProposalProcedure>());
-          reader.readStartArray();
-
-          while (reader.peekState() !== CborReaderState.EndArray) {
-            body.proposalProcedures()!.push(ProposalProcedure.fromCbor(HexBlob.fromBytes(reader.readEncodedValue())));
-          }
-
-          reader.readEndArray();
+          body.setProposalProcedures(
+            CborSet.fromCbor(HexBlob.fromBytes(reader.readEncodedValue()), ProposalProcedure.fromCbor)
+          );
           break;
         case 21n:
           body.setCurrentTreasuryValue(reader.readInt());
@@ -456,20 +399,18 @@ export class TransactionBody {
   toCore(): Cardano.TxBody {
     return {
       auxiliaryDataHash: this.#auxiliaryDataHash,
-      certificates: this.#certs ? this.#certs.map((cert) => cert.toCore()) : undefined,
+      certificates: this.#certs?.values() ? this.#certs.toCore() : undefined,
       collateralReturn: this.#collateralReturn?.toCore(),
-      collaterals: this.#collateral ? this.#collateral.map((input) => input.toCore()) : undefined,
+      collaterals: this.#collateral?.values() ? this.#collateral.toCore() : undefined,
       donation: this.#donation,
       fee: this.#fee,
-      inputs: this.#inputs.map((input) => input.toCore()),
+      inputs: this.#inputs.toCore(),
       mint: this.#mint,
       networkId: this.#networkId,
       outputs: this.#outputs.map((output) => output.toCore()),
-      proposalProcedures: this.#proposalProcedures
-        ? this.#proposalProcedures.map((input) => input.toCore())
-        : undefined,
-      referenceInputs: this.#referenceInputs ? this.#referenceInputs.map((input) => input.toCore()) : undefined,
-      requiredExtraSignatures: this.#requiredSigners,
+      proposalProcedures: this.#proposalProcedures?.values() ? this.#proposalProcedures.toCore() : undefined,
+      referenceInputs: this.#referenceInputs?.size() ? this.#referenceInputs.toCore() : undefined,
+      requiredExtraSignatures: this.#requiredSigners?.toCore(),
       scriptIntegrityHash: this.#scriptDataHash,
       totalCollateral: this.#totalCollateral,
       treasuryValue: this.#currentTreasuryValue,
@@ -495,7 +436,8 @@ export class TransactionBody {
    */
   static fromCore(coreTransactionBody: Cardano.TxBody): TransactionBody {
     const body = new TransactionBody(
-      coreTransactionBody.inputs.map((input) => TransactionInput.fromCore(input)),
+      CborSet.fromCore(coreTransactionBody.inputs, TransactionInput.fromCore),
+      // new CborSet<TransactionInput>(coreTransactionBody.inputs.map((input) => TransactionInput.fromCore(input))),
       coreTransactionBody.outputs.map((output) => TransactionOutput.fromCore(output)),
       coreTransactionBody.fee
     );
@@ -503,23 +445,23 @@ export class TransactionBody {
     if (coreTransactionBody.auxiliaryDataHash) body.setAuxiliaryDataHash(coreTransactionBody.auxiliaryDataHash);
 
     if (coreTransactionBody.certificates)
-      body.setCerts(coreTransactionBody.certificates.map((cert) => Certificate.fromCore(cert)));
+      body.setCerts(CborSet.fromCore(coreTransactionBody.certificates, Certificate.fromCore));
 
     if (coreTransactionBody.collateralReturn)
       body.setCollateralReturn(TransactionOutput.fromCore(coreTransactionBody.collateralReturn));
 
     if (coreTransactionBody.collaterals)
-      body.setCollateral(coreTransactionBody.collaterals.map((input) => TransactionInput.fromCore(input)));
+      body.setCollateral(CborSet.fromCore(coreTransactionBody.collaterals, TransactionInput.fromCore));
 
     if (coreTransactionBody.mint) body.setMint(coreTransactionBody.mint);
 
     if (coreTransactionBody.networkId) body.setNetworkId(coreTransactionBody.networkId);
 
     if (coreTransactionBody.referenceInputs)
-      body.setReferenceInputs(coreTransactionBody.referenceInputs.map((input) => TransactionInput.fromCore(input)));
+      body.setReferenceInputs(CborSet.fromCore(coreTransactionBody.referenceInputs, TransactionInput.fromCore));
 
     if (coreTransactionBody.requiredExtraSignatures)
-      body.setRequiredSigners(coreTransactionBody.requiredExtraSignatures);
+      body.setRequiredSigners(CborSet.fromCore(coreTransactionBody.requiredExtraSignatures, Hash.fromCore));
 
     if (coreTransactionBody.scriptIntegrityHash) body.setScriptDataHash(coreTransactionBody.scriptIntegrityHash);
 
@@ -547,9 +489,7 @@ export class TransactionBody {
     if (coreTransactionBody.votingProcedures)
       body.setVotingProcedures(VotingProcedures.fromCore(coreTransactionBody.votingProcedures));
     if (coreTransactionBody.proposalProcedures)
-      body.setProposalProcedures(
-        coreTransactionBody.proposalProcedures.map((core) => ProposalProcedure.fromCore(core))
-      );
+      body.setProposalProcedures(CborSet.fromCore(coreTransactionBody.proposalProcedures, ProposalProcedure.fromCore));
 
     return body;
   }
@@ -560,7 +500,7 @@ export class TransactionBody {
    *
    * @param inputs the list of references to UTxOs.
    */
-  setInputs(inputs: Array<TransactionInput>) {
+  setInputs(inputs: TransactionInputSet) {
     this.#inputs = inputs;
     this.#originalBytes = undefined;
   }
@@ -571,7 +511,7 @@ export class TransactionBody {
    *
    * @returns The list of references to UTxOs.
    */
-  inputs(): Array<TransactionInput> {
+  inputs() {
     return this.#inputs;
   }
 
@@ -644,7 +584,7 @@ export class TransactionBody {
    *
    * @param certs The certificates to be issued by this transaction.
    */
-  setCerts(certs: Array<Certificate>): void {
+  setCerts(certs: CborSet<ReturnType<Certificate['toCore']>, Certificate>): void {
     this.#certs = certs;
     this.#originalBytes = undefined;
   }
@@ -655,7 +595,7 @@ export class TransactionBody {
    *
    * @returns The certificates to be issued by this transaction.
    */
-  certs(): Array<Certificate> | undefined {
+  certs() {
     return this.#certs;
   }
 
@@ -785,7 +725,7 @@ export class TransactionBody {
    *
    * @param collateral The UTxOs that a sender commits to forfeit.
    */
-  setCollateral(collateral: Array<TransactionInput>): void {
+  setCollateral(collateral: TransactionInputSet): void {
     this.#collateral = collateral;
     this.#originalBytes = undefined;
   }
@@ -796,7 +736,7 @@ export class TransactionBody {
    *
    * @returns The UTxOs that a sender commits to forfeit.
    */
-  collateral(): Array<TransactionInput> | undefined {
+  collateral() {
     return this.#collateral;
   }
 
@@ -805,7 +745,7 @@ export class TransactionBody {
    *
    * @param requiredSigners The set of keys which need to sign a transaction
    */
-  setRequiredSigners(requiredSigners: Array<Crypto.Ed25519KeyHashHex>): void {
+  setRequiredSigners(requiredSigners: CborSet<Crypto.Ed25519KeyHashHex, Hash<Crypto.Ed25519KeyHashHex>>): void {
     this.#requiredSigners = requiredSigners;
     this.#originalBytes = undefined;
   }
@@ -815,7 +755,7 @@ export class TransactionBody {
    *
    * @returns The set of keys which need to sign a transaction
    */
-  requiredSigners(): Array<Crypto.Ed25519KeyHashHex> | undefined {
+  requiredSigners() {
     return this.#requiredSigners;
   }
 
@@ -891,7 +831,7 @@ export class TransactionBody {
    * Reference inputs allows looking at an output without spending it. This facilitates access to information
    * stored on the blockchain without the need of spending and recreating UTxOs.
    */
-  setReferenceInputs(referenceInputs: Array<TransactionInput>): void {
+  setReferenceInputs(referenceInputs: TransactionInputSet): void {
     this.#referenceInputs = referenceInputs;
     this.#originalBytes = undefined;
   }
@@ -901,7 +841,7 @@ export class TransactionBody {
    *
    * @returns the reference inputs.
    */
-  referenceInputs(): Array<TransactionInput> | undefined {
+  referenceInputs() {
     return this.#referenceInputs;
   }
 
@@ -929,7 +869,7 @@ export class TransactionBody {
    *
    * @param proposalProcedure the proposal procedures.
    */
-  setProposalProcedures(proposalProcedure: Array<ProposalProcedure>): void {
+  setProposalProcedures(proposalProcedure: CborSet<ReturnType<ProposalProcedure['toCore']>, ProposalProcedure>): void {
     this.#proposalProcedures = proposalProcedure;
     this.#originalBytes = undefined;
   }
@@ -939,7 +879,7 @@ export class TransactionBody {
    *
    * @returns the proposal procedures.
    */
-  proposalProcedures(): Array<ProposalProcedure> | undefined {
+  proposalProcedures() {
     return this.#proposalProcedures;
   }
 
@@ -989,25 +929,25 @@ export class TransactionBody {
   #getMapSize(): number {
     let mapSize = 0;
 
-    if (this.#inputs !== undefined && this.#inputs.length > 0) ++mapSize;
+    if (this.#inputs !== undefined && this.#inputs.size() > 0) ++mapSize;
     if (this.#outputs !== undefined && this.#outputs.length > 0) ++mapSize;
     if (this.#fee !== undefined) ++mapSize;
     if (this.#ttl !== undefined) ++mapSize;
-    if (this.#certs !== undefined && this.#certs.length > 0) ++mapSize;
+    if (this.#certs !== undefined && this.#certs.size() > 0) ++mapSize;
     if (this.#withdrawals !== undefined && this.#withdrawals.size > 0) ++mapSize;
     if (this.#update !== undefined) ++mapSize;
     if (this.#auxiliaryDataHash !== undefined) ++mapSize;
     if (this.#validityStartInterval !== undefined) ++mapSize;
     if (this.#mint !== undefined && this.#mint.size > 0) ++mapSize;
     if (this.#scriptDataHash !== undefined) ++mapSize;
-    if (this.#collateral !== undefined && this.#collateral.length > 0) ++mapSize;
-    if (this.#requiredSigners !== undefined && this.#requiredSigners.length > 0) ++mapSize;
+    if (this.#collateral !== undefined && this.#collateral.size() > 0) ++mapSize;
+    if (this.#requiredSigners?.values() !== undefined && this.#requiredSigners.size() > 0) ++mapSize;
     if (this.#networkId !== undefined) ++mapSize;
     if (this.#collateralReturn !== undefined) ++mapSize;
     if (this.#totalCollateral !== undefined) ++mapSize;
-    if (this.#referenceInputs !== undefined && this.#referenceInputs.length > 0) ++mapSize;
+    if (this.#referenceInputs !== undefined && this.#referenceInputs.size() > 0) ++mapSize;
     if (this.#votingProcedures !== undefined) ++mapSize;
-    if (this.#proposalProcedures !== undefined && this.#proposalProcedures.length > 0) ++mapSize;
+    if (this.#proposalProcedures !== undefined && this.#proposalProcedures.size() > 0) ++mapSize;
     if (this.#currentTreasuryValue !== undefined) ++mapSize;
     if (this.#donation !== undefined) ++mapSize;
 
diff --git a/packages/core/src/Serialization/TransactionWitnessSet/TransactionWitnessSet.ts b/packages/core/src/Serialization/TransactionWitnessSet/TransactionWitnessSet.ts
index 7408a25b9d5..c8b73b9e56e 100644
--- a/packages/core/src/Serialization/TransactionWitnessSet/TransactionWitnessSet.ts
+++ b/packages/core/src/Serialization/TransactionWitnessSet/TransactionWitnessSet.ts
@@ -2,20 +2,23 @@
 import * as Cardano from '../../Cardano';
 import { BootstrapWitness } from './BootstrapWitness';
 import { CborReader, CborReaderState, CborWriter } from '../CBOR';
+import { CborSet } from '../Common';
 import { HexBlob } from '@cardano-sdk/util';
 import { NativeScript, PlutusV1Script, PlutusV2Script, PlutusV3Script } from '../Scripts';
 import { PlutusData } from '../PlutusData/PlutusData';
 import { Redeemer } from './Redeemer';
 import { SerializationError, SerializationFailure } from '../../errors';
 import { VkeyWitness } from './VkeyWitness';
+import { hexToBytes } from '../../util/misc';
+import _groupBy from 'lodash/groupBy';
 import uniqWith from 'lodash/uniqWith';
 
 /** This type represents the segregated CDDL scripts. */
 type CddlScripts = {
-  native: Array<NativeScript> | undefined;
-  plutusV1: Array<PlutusV1Script> | undefined;
-  plutusV2: Array<PlutusV2Script> | undefined;
-  plutusV3: Array<PlutusV3Script> | undefined;
+  native?: CborSet<ReturnType<NativeScript['toCore']>, NativeScript>;
+  plutusV1?: CborSet<ReturnType<PlutusV1Script['toCore']>, PlutusV1Script>;
+  plutusV2?: CborSet<ReturnType<PlutusV2Script['toCore']>, PlutusV2Script>;
+  plutusV3?: CborSet<ReturnType<PlutusV3Script['toCore']>, PlutusV3Script>;
 };
 
 /**
@@ -27,14 +30,14 @@ type CddlScripts = {
  * smart contract execution.
  */
 export class TransactionWitnessSet {
-  #vkeywitnesses: Array<VkeyWitness> | undefined;
-  #nativeScripts: Array<NativeScript> | undefined;
-  #bootstrapWitnesses: Array<BootstrapWitness> | undefined;
-  #plutusV1Scripts: Array<PlutusV1Script> | undefined;
-  #plutusData: Array<PlutusData> | undefined;
+  #vkeywitnesses: CborSet<ReturnType<VkeyWitness['toCore']>, VkeyWitness> | undefined;
+  #nativeScripts: CborSet<ReturnType<NativeScript['toCore']>, NativeScript> | undefined;
+  #bootstrapWitnesses: CborSet<ReturnType<BootstrapWitness['toCore']>, BootstrapWitness> | undefined;
+  #plutusV1Scripts: CborSet<ReturnType<PlutusV1Script['toCore']>, PlutusV1Script> | undefined;
+  #plutusData: CborSet<ReturnType<PlutusData['toCore']>, PlutusData> | undefined;
   #redeemers: Array<Redeemer> | undefined;
-  #plutusV2Scripts: Array<PlutusV2Script> | undefined;
-  #plutusV3Scripts: Array<PlutusV3Script> | undefined;
+  #plutusV2Scripts: CborSet<ReturnType<PlutusV2Script['toCore']>, PlutusV2Script> | undefined;
+  #plutusV3Scripts: CborSet<ReturnType<PlutusV3Script['toCore']>, PlutusV3Script> | undefined;
   #originalBytes: HexBlob | undefined = undefined;
 
   /**
@@ -49,64 +52,48 @@ export class TransactionWitnessSet {
 
     // CDDL
     // transaction_witness_set =
-    //   { ? 0: [* vkeywitness ]
-    //   , ? 1: [* native_script ]
-    //   , ? 2: [* bootstrap_witness ]
-    //   , ? 3: [* plutus_v1_script ]
-    //   , ? 4: [* plutus_data ]
-    //   , ? 5: [* redeemer ]
-    //   , ? 6: [* plutus_v2_script ]
-    //   , ? 7: [* plutus_v3_script ]
+    //   { ? 0: nonempty_set<vkeywitness>
+    //   , ? 1: nonempty_set<native_script>
+    //   , ? 2: nonempty_set<bootstrap_witness>
+    //   , ? 3: nonempty_set<plutus_v1_script>
+    //   , ? 4: nonempty_set<plutus_data>
+    //   , ? 5: redeemers
+    //   , ? 6: nonempty_set<plutus_v2_script>
+    //   , ? 7: nonempty_set<plutus_v3_script>
     //   }
+    //
+    // redeemers =
+    //   [ + [ tag: redeemer_tag, index: uint, data: plutus_data, ex_units: ex_units ] ]
+    //   / { + [ tag: redeemer_tag, index: uint ] => [ data: plutus_data, ex_units: ex_units ] }
     writer.writeStartMap(this.#getMapSize());
 
-    if (this.#vkeywitnesses && this.#vkeywitnesses.length > 0) {
-      const uniqueWitnesses = uniqWith(this.#vkeywitnesses, (lhs, rhs) => lhs.vkey() === rhs.vkey());
-
+    if (this.#vkeywitnesses && this.#vkeywitnesses.size() > 0) {
+      this.#vkeywitnesses.setValues(uniqWith(this.#vkeywitnesses.values(), (lhs, rhs) => lhs.vkey() === rhs.vkey()));
       writer.writeInt(0n);
-      writer.writeStartArray(uniqueWitnesses.length);
-
-      for (const witness of uniqueWitnesses) {
-        writer.writeEncodedValue(Buffer.from(witness.toCbor(), 'hex'));
-      }
+      writer.writeEncodedValue(Buffer.from(this.#vkeywitnesses.toCbor(), 'hex'));
     }
 
-    if (this.#nativeScripts && this.#nativeScripts.length > 0) {
+    if (this.#nativeScripts && this.#nativeScripts.size() > 0) {
       writer.writeInt(1n);
-      writer.writeStartArray(this.#nativeScripts.length);
-
-      for (const script of this.#nativeScripts) {
-        writer.writeEncodedValue(Buffer.from(script.toCbor(), 'hex'));
-      }
+      writer.writeEncodedValue(Buffer.from(this.#nativeScripts.toCbor(), 'hex'));
     }
 
-    if (this.#bootstrapWitnesses && this.#bootstrapWitnesses.length > 0) {
-      const uniqueWitnesses = uniqWith(this.#bootstrapWitnesses, (lhs, rhs) => lhs.vkey() === rhs.vkey());
-
+    if (this.#bootstrapWitnesses && this.#bootstrapWitnesses.size() > 0) {
+      this.#bootstrapWitnesses.setValues(
+        uniqWith(this.#bootstrapWitnesses.values(), (lhs, rhs) => lhs.vkey() === rhs.vkey())
+      );
       writer.writeInt(2n);
-      writer.writeStartArray(uniqueWitnesses.length);
-
-      for (const witness of uniqueWitnesses) {
-        writer.writeEncodedValue(Buffer.from(witness.toCbor(), 'hex'));
-      }
+      writer.writeEncodedValue(Buffer.from(this.#bootstrapWitnesses.toCbor(), 'hex'));
     }
 
-    if (this.#plutusV1Scripts && this.#plutusV1Scripts.length > 0) {
+    if (this.#plutusV1Scripts && this.#plutusV1Scripts.size() > 0) {
       writer.writeInt(3n);
-      writer.writeStartArray(this.#plutusV1Scripts.length);
-
-      for (const script of this.#plutusV1Scripts) {
-        writer.writeEncodedValue(Buffer.from(script.toCbor(), 'hex'));
-      }
+      writer.writeEncodedValue(Buffer.from(this.#plutusV1Scripts.toCbor(), 'hex'));
     }
 
-    if (this.#plutusData && this.#plutusData.length > 0) {
+    if (this.#plutusData && this.#plutusData.size() > 0) {
       writer.writeInt(4n);
-      writer.writeStartArray(this.#plutusData.length);
-
-      for (const data of this.#plutusData) {
-        writer.writeEncodedValue(Buffer.from(data.toCbor(), 'hex'));
-      }
+      writer.writeEncodedValue(Buffer.from(this.#plutusData.toCbor(), 'hex'));
     }
 
     if (this.#redeemers && this.#redeemers.length > 0) {
@@ -118,22 +105,14 @@ export class TransactionWitnessSet {
       }
     }
 
-    if (this.#plutusV2Scripts && this.#plutusV2Scripts.length > 0) {
+    if (this.#plutusV2Scripts && this.#plutusV2Scripts.size() > 0) {
       writer.writeInt(6n);
-      writer.writeStartArray(this.#plutusV2Scripts.length);
-
-      for (const script of this.#plutusV2Scripts) {
-        writer.writeEncodedValue(Buffer.from(script.toCbor(), 'hex'));
-      }
+      writer.writeEncodedValue(Buffer.from(this.#plutusV2Scripts.toCbor(), 'hex'));
     }
 
-    if (this.#plutusV3Scripts && this.#plutusV3Scripts.length > 0) {
+    if (this.#plutusV3Scripts && this.#plutusV3Scripts.size() > 0) {
       writer.writeInt(7n);
-      writer.writeStartArray(this.#plutusV3Scripts.length);
-
-      for (const script of this.#plutusV3Scripts) {
-        writer.writeEncodedValue(Buffer.from(script.toCbor(), 'hex'));
-      }
+      writer.writeEncodedValue(Buffer.from(this.#plutusV3Scripts.toCbor(), 'hex'));
     }
 
     return writer.encodeAsHex();
@@ -157,54 +136,25 @@ export class TransactionWitnessSet {
 
       switch (key) {
         case 0n:
-          witness.setVkeys(new Array<VkeyWitness>());
-          reader.readStartArray();
-
-          while (reader.peekState() !== CborReaderState.EndArray) {
-            witness.vkeys()!.push(VkeyWitness.fromCbor(HexBlob.fromBytes(reader.readEncodedValue())));
-          }
-
-          reader.readEndArray();
+          witness.setVkeys(CborSet.fromCbor(HexBlob.fromBytes(reader.readEncodedValue()), VkeyWitness.fromCbor));
           break;
         case 1n:
-          witness.setNativeScripts(new Array<NativeScript>());
-          reader.readStartArray();
-
-          while (reader.peekState() !== CborReaderState.EndArray) {
-            witness.nativeScripts()!.push(NativeScript.fromCbor(HexBlob.fromBytes(reader.readEncodedValue())));
-          }
-
-          reader.readEndArray();
+          witness.setNativeScripts(
+            CborSet.fromCbor(HexBlob.fromBytes(reader.readEncodedValue()), NativeScript.fromCbor)
+          );
           break;
         case 2n:
-          witness.setBootstraps(new Array<BootstrapWitness>());
-          reader.readStartArray();
-
-          while (reader.peekState() !== CborReaderState.EndArray) {
-            witness.bootstraps()!.push(BootstrapWitness.fromCbor(HexBlob.fromBytes(reader.readEncodedValue())));
-          }
-
-          reader.readEndArray();
+          witness.setBootstraps(
+            CborSet.fromCbor(HexBlob.fromBytes(reader.readEncodedValue()), BootstrapWitness.fromCbor)
+          );
           break;
         case 3n:
-          witness.setPlutusV1Scripts(new Array<PlutusV1Script>());
-          reader.readStartArray();
-
-          while (reader.peekState() !== CborReaderState.EndArray) {
-            witness.plutusV1Scripts()!.push(PlutusV1Script.fromCbor(HexBlob.fromBytes(reader.readEncodedValue())));
-          }
-
-          reader.readEndArray();
+          witness.setPlutusV1Scripts(
+            CborSet.fromCbor(HexBlob.fromBytes(reader.readEncodedValue()), PlutusV1Script.fromCbor)
+          );
           break;
         case 4n:
-          witness.setPlutusData(new Array<PlutusData>());
-          reader.readStartArray();
-
-          while (reader.peekState() !== CborReaderState.EndArray) {
-            witness.plutusData()!.push(PlutusData.fromCbor(HexBlob.fromBytes(reader.readEncodedValue())));
-          }
-
-          reader.readEndArray();
+          witness.setPlutusData(CborSet.fromCbor(HexBlob.fromBytes(reader.readEncodedValue()), PlutusData.fromCbor));
           break;
         case 5n:
           witness.setRedeemers(new Array<Redeemer>());
@@ -217,24 +167,14 @@ export class TransactionWitnessSet {
           reader.readEndArray();
           break;
         case 6n:
-          witness.setPlutusV2Scripts(new Array<PlutusV2Script>());
-          reader.readStartArray();
-
-          while (reader.peekState() !== CborReaderState.EndArray) {
-            witness.plutusV2Scripts()!.push(PlutusV2Script.fromCbor(HexBlob.fromBytes(reader.readEncodedValue())));
-          }
-
-          reader.readEndArray();
+          witness.setPlutusV2Scripts(
+            CborSet.fromCbor(HexBlob.fromBytes(reader.readEncodedValue()), PlutusV2Script.fromCbor)
+          );
           break;
         case 7n:
-          witness.setPlutusV3Scripts(new Array<PlutusV3Script>());
-          reader.readStartArray();
-
-          while (reader.peekState() !== CborReaderState.EndArray) {
-            witness.plutusV3Scripts()!.push(PlutusV3Script.fromCbor(HexBlob.fromBytes(reader.readEncodedValue())));
-          }
-
-          reader.readEndArray();
+          witness.setPlutusV3Scripts(
+            CborSet.fromCbor(HexBlob.fromBytes(reader.readEncodedValue()), PlutusV3Script.fromCbor)
+          );
           break;
       }
     }
@@ -254,11 +194,11 @@ export class TransactionWitnessSet {
   toCore(): Cardano.Witness {
     const scripts = this.#getCoreScripts();
     return {
-      bootstrap: this.#bootstrapWitnesses ? this.#bootstrapWitnesses.map((witness) => witness.toCore()) : undefined,
-      datums: this.#plutusData ? this.#plutusData.map((data) => data.toCore()) : undefined,
+      bootstrap: this.#bootstrapWitnesses ? this.#bootstrapWitnesses.toCore() : undefined,
+      datums: this.#plutusData ? this.#plutusData.toCore() : undefined,
       redeemers: this.#redeemers ? this.#redeemers.map((data) => data.toCore()) : undefined,
       scripts: scripts.length > 0 ? scripts : undefined,
-      signatures: this.#vkeywitnesses ? new Map(this.#vkeywitnesses.map((witness) => witness.toCore())) : new Map()
+      signatures: this.#vkeywitnesses ? new Map(this.#vkeywitnesses.toCore()) : new Map()
     };
   }
 
@@ -271,7 +211,7 @@ export class TransactionWitnessSet {
     const witness = new TransactionWitnessSet();
 
     if (coreWitness.signatures) {
-      witness.setVkeys([...coreWitness.signatures].map((vkWitness) => VkeyWitness.fromCore(vkWitness)));
+      witness.setVkeys(CborSet.fromCore([...coreWitness.signatures], VkeyWitness.fromCore));
     }
 
     if (coreWitness.scripts) {
@@ -288,11 +228,11 @@ export class TransactionWitnessSet {
     }
 
     if (coreWitness.datums) {
-      witness.setPlutusData(coreWitness.datums.map((data) => PlutusData.fromCore(data)));
+      witness.setPlutusData(CborSet.fromCore(coreWitness.datums, PlutusData.fromCore));
     }
 
     if (coreWitness.bootstrap) {
-      witness.setBootstraps(coreWitness.bootstrap.map((bootstrap) => BootstrapWitness.fromCore(bootstrap)));
+      witness.setBootstraps(CborSet.fromCore(coreWitness.bootstrap, BootstrapWitness.fromCore));
     }
 
     return witness;
@@ -304,7 +244,7 @@ export class TransactionWitnessSet {
    *
    * @param vkeys The set of verification key witnesses.
    */
-  setVkeys(vkeys: Array<VkeyWitness>) {
+  setVkeys(vkeys: CborSet<ReturnType<VkeyWitness['toCore']>, VkeyWitness>) {
     this.#vkeywitnesses = vkeys;
     this.#originalBytes = undefined;
   }
@@ -315,7 +255,7 @@ export class TransactionWitnessSet {
    *
    * @returns The set of verification key witnesses.
    */
-  vkeys(): Array<VkeyWitness> | undefined {
+  vkeys() {
     return this.#vkeywitnesses;
   }
 
@@ -324,7 +264,7 @@ export class TransactionWitnessSet {
    *
    * @param nativeScripts The set of native scripts.
    */
-  setNativeScripts(nativeScripts: Array<NativeScript>) {
+  setNativeScripts(nativeScripts: CborSet<ReturnType<NativeScript['toCore']>, NativeScript>) {
     this.#nativeScripts = nativeScripts;
     this.#originalBytes = undefined;
   }
@@ -334,7 +274,7 @@ export class TransactionWitnessSet {
    *
    * @returns The set of native scripts.
    */
-  nativeScripts(): Array<NativeScript> | undefined {
+  nativeScripts() {
     return this.#nativeScripts;
   }
 
@@ -343,7 +283,7 @@ export class TransactionWitnessSet {
    *
    * @param bootstraps The Bootstrap witnesses for this transaction.
    */
-  setBootstraps(bootstraps: Array<BootstrapWitness>) {
+  setBootstraps(bootstraps: CborSet<ReturnType<BootstrapWitness['toCore']>, BootstrapWitness>) {
     this.#bootstrapWitnesses = bootstraps;
     this.#originalBytes = undefined;
   }
@@ -353,7 +293,7 @@ export class TransactionWitnessSet {
    *
    * @returns The Bootstrap witnesses for this transaction.
    */
-  bootstraps(): Array<BootstrapWitness> | undefined {
+  bootstraps() {
     return this.#bootstrapWitnesses;
   }
 
@@ -362,7 +302,7 @@ export class TransactionWitnessSet {
    *
    * @param plutusV1Scripts The set of plutus v1 scripts.
    */
-  setPlutusV1Scripts(plutusV1Scripts: Array<PlutusV1Script>) {
+  setPlutusV1Scripts(plutusV1Scripts: CborSet<ReturnType<PlutusV1Script['toCore']>, PlutusV1Script>) {
     this.#plutusV1Scripts = plutusV1Scripts;
     this.#originalBytes = undefined;
   }
@@ -372,7 +312,7 @@ export class TransactionWitnessSet {
    *
    * @returns The set of plutus v1 scripts.
    */
-  plutusV1Scripts(): Array<PlutusV1Script> | undefined {
+  plutusV1Scripts() {
     return this.#plutusV1Scripts;
   }
 
@@ -381,7 +321,7 @@ export class TransactionWitnessSet {
    *
    * @param plutusData The Plutus Data.
    */
-  setPlutusData(plutusData: Array<PlutusData>) {
+  setPlutusData(plutusData: CborSet<ReturnType<PlutusData['toCore']>, PlutusData>) {
     this.#plutusData = plutusData;
     this.#originalBytes = undefined;
   }
@@ -391,7 +331,7 @@ export class TransactionWitnessSet {
    *
    * @returns The Plutus Data.
    */
-  plutusData(): Array<PlutusData> | undefined {
+  plutusData() {
     return this.#plutusData;
   }
 
@@ -419,7 +359,7 @@ export class TransactionWitnessSet {
    *
    * @param plutusV2Scripts The set of plutus v2 scripts.
    */
-  setPlutusV2Scripts(plutusV2Scripts: Array<PlutusV2Script>) {
+  setPlutusV2Scripts(plutusV2Scripts: CborSet<ReturnType<PlutusV2Script['toCore']>, PlutusV2Script>) {
     this.#plutusV2Scripts = plutusV2Scripts;
     this.#originalBytes = undefined;
   }
@@ -429,7 +369,7 @@ export class TransactionWitnessSet {
    *
    * @returns The set of plutus v2 scripts.
    */
-  plutusV2Scripts(): Array<PlutusV2Script> | undefined {
+  plutusV2Scripts() {
     return this.#plutusV2Scripts;
   }
 
@@ -438,7 +378,7 @@ export class TransactionWitnessSet {
    *
    * @param plutusV3Scripts The set of plutus v3 scripts.
    */
-  setPlutusV3Scripts(plutusV3Scripts: Array<PlutusV3Script>) {
+  setPlutusV3Scripts(plutusV3Scripts: CborSet<ReturnType<PlutusV3Script['toCore']>, PlutusV3Script>) {
     this.#plutusV3Scripts = plutusV3Scripts;
     this.#originalBytes = undefined;
   }
@@ -448,7 +388,7 @@ export class TransactionWitnessSet {
    *
    * @returns The set of plutus v3 scripts.
    */
-  plutusV3Scripts(): Array<PlutusV3Script> | undefined {
+  plutusV3Scripts() {
     return this.#plutusV3Scripts;
   }
 
@@ -459,10 +399,10 @@ export class TransactionWitnessSet {
    * @private
    */
   #getCoreScripts(): Array<Cardano.Script> {
-    const plutusV1 = this.#plutusV1Scripts ? this.#plutusV1Scripts.map((script) => script.toCore()) : [];
-    const plutusV2 = this.#plutusV2Scripts ? this.#plutusV2Scripts.map((script) => script.toCore()) : [];
-    const plutusV3 = this.#plutusV3Scripts ? this.#plutusV3Scripts.map((script) => script.toCore()) : [];
-    const native = this.#nativeScripts ? this.#nativeScripts.map((script) => script.toCore()) : [];
+    const plutusV1 = this.#plutusV1Scripts ? this.#plutusV1Scripts.toCore() : [];
+    const plutusV2 = this.#plutusV2Scripts ? this.#plutusV2Scripts.toCore() : [];
+    const plutusV3 = this.#plutusV3Scripts ? this.#plutusV3Scripts.toCore() : [];
+    const native = this.#nativeScripts ? this.#nativeScripts.toCore() : [];
 
     return [...plutusV1, ...plutusV2, ...plutusV3, ...native];
   }
@@ -474,36 +414,46 @@ export class TransactionWitnessSet {
    * @private
    */
   static #getCddlScripts(scripts: Array<Cardano.Script>): CddlScripts {
-    const result: CddlScripts = { native: undefined, plutusV1: undefined, plutusV2: undefined, plutusV3: undefined };
-
-    for (const script of scripts) {
-      switch (script.__type) {
-        case Cardano.ScriptType.Native:
-          if (!result.native) result.native = new Array<NativeScript>();
-
-          result.native.push(NativeScript.fromCore(script));
+    const [coreNative, coreV1, coreV2, coreV3] = scripts.reduce<
+      [
+        Cardano.NativeScript[] | null,
+        Cardano.PlutusScript[] | null,
+        Cardano.PlutusScript[] | null,
+        Cardano.PlutusScript[] | null
+      ]
+    >(
+      ([native, v1, v2, v3], script) => {
+        if (script.__type === Cardano.ScriptType.Native) {
+          native ? native.push(script) : (native = [script]);
+        } else {
+          switch (script.version) {
+            case Cardano.PlutusLanguageVersion.V1:
+              v1 ? v1.push(script) : (v1 = [script]);
+              break;
+            case Cardano.PlutusLanguageVersion.V2:
+              v2 ? v2.push(script) : (v2 = [script]);
           break;
-        case Cardano.ScriptType.Plutus:
-          if (script.version === Cardano.PlutusLanguageVersion.V1) {
-            if (!result.plutusV1) result.plutusV1 = new Array<PlutusV1Script>();
-
-            result.plutusV1.push(PlutusV1Script.fromCore(script));
-          } else if (script.version === Cardano.PlutusLanguageVersion.V2) {
-            if (!result.plutusV2) result.plutusV2 = new Array<PlutusV2Script>();
-
-            result.plutusV2.push(PlutusV2Script.fromCore(script));
-          } else if (script.version === Cardano.PlutusLanguageVersion.V3) {
-            if (!result.plutusV3) result.plutusV3 = new Array<PlutusV3Script>();
-
-            result.plutusV3.push(PlutusV3Script.fromCore(script));
-          }
+            case Cardano.PlutusLanguageVersion.V3:
+              v3 ? v3.push(script) : (v3 = [script]);
           break;
         default:
-          throw new SerializationError(SerializationFailure.InvalidScriptType, `Script '${script}' is not supported.`);
+              throw new SerializationError(
+                SerializationFailure.InvalidScriptType,
+                `Script '${script}' is not supported.`
+              );
       }
     }
+        return [native, v1, v2, v3];
+      },
+      [null, null, null, null]
+    );
 
-    return result;
+    return {
+      ...(coreNative && { native: CborSet.fromCore(coreNative, NativeScript.fromCore) }),
+      ...(coreV1 && { plutusV1: CborSet.fromCore(coreV1, PlutusV1Script.fromCore) }),
+      ...(coreV2 && { plutusV2: CborSet.fromCore(coreV2, PlutusV2Script.fromCore) }),
+      ...(coreV3 && { plutusV3: CborSet.fromCore(coreV3, PlutusV3Script.fromCore) })
+    };
   }
 
   /**
@@ -514,14 +464,14 @@ export class TransactionWitnessSet {
   #getMapSize(): number {
     let mapSize = 0;
 
-    if (this.#vkeywitnesses !== undefined && this.#vkeywitnesses.length > 0) ++mapSize;
-    if (this.#nativeScripts !== undefined && this.#nativeScripts.length > 0) ++mapSize;
-    if (this.#bootstrapWitnesses !== undefined && this.#bootstrapWitnesses.length > 0) ++mapSize;
-    if (this.#plutusV1Scripts !== undefined && this.#plutusV1Scripts.length > 0) ++mapSize;
-    if (this.#plutusData !== undefined && this.#plutusData.length > 0) ++mapSize;
+    if (this.#vkeywitnesses !== undefined && this.#vkeywitnesses.size() > 0) ++mapSize;
+    if (this.#nativeScripts !== undefined && this.#nativeScripts.size() > 0) ++mapSize;
+    if (this.#bootstrapWitnesses !== undefined && this.#bootstrapWitnesses.size() > 0) ++mapSize;
+    if (this.#plutusV1Scripts !== undefined && this.#plutusV1Scripts.size() > 0) ++mapSize;
+    if (this.#plutusData !== undefined && this.#plutusData.size() > 0) ++mapSize;
     if (this.#redeemers !== undefined && this.#redeemers.length > 0) ++mapSize;
-    if (this.#plutusV2Scripts !== undefined && this.#plutusV2Scripts.length > 0) ++mapSize;
-    if (this.#plutusV3Scripts !== undefined && this.#plutusV3Scripts.length > 0) ++mapSize;
+    if (this.#plutusV2Scripts !== undefined && this.#plutusV2Scripts.size() > 0) ++mapSize;
+    if (this.#plutusV3Scripts !== undefined && this.#plutusV3Scripts.size() > 0) ++mapSize;
 
     return mapSize;
   }
diff --git a/packages/core/test/Serialization/Certificates/Certificate.test.ts b/packages/core/test/Serialization/Certificates/Certificate.test.ts
index 54c29bee84a..d32e624dcf9 100644
--- a/packages/core/test/Serialization/Certificates/Certificate.test.ts
+++ b/packages/core/test/Serialization/Certificates/Certificate.test.ts
@@ -344,6 +344,7 @@ describe('Certificate', () => {
       expect(
         params
           .poolOwners()
+          .toCore()
           .map((keyHash) => Cardano.createRewardAccount(keyHash, params.rewardAccount().toAddress().getNetworkId()))
       ).toEqual([Cardano.RewardAccount('stake1u89sasnfyjtmgk8ydqfv3fdl52f36x3djedfnzfc9rkgzrcss5vgr')]);
       expect(params.relays().map((relay) => relay.toCore())).toEqual([
@@ -392,6 +393,7 @@ describe('Certificate', () => {
       expect(
         params
           .poolOwners()
+          .toCore()
           .map((keyHash) => Cardano.createRewardAccount(keyHash, params.rewardAccount().toAddress().getNetworkId()))
       ).toEqual([Cardano.RewardAccount('stake1u89sasnfyjtmgk8ydqfv3fdl52f36x3djedfnzfc9rkgzrcss5vgr')]);
       expect(params.relays().map((relay) => relay.toCore())).toEqual([
diff --git a/packages/core/test/Serialization/Certificates/PoolParams/PoolParams.test.ts b/packages/core/test/Serialization/Certificates/PoolParams/PoolParams.test.ts
index 2490ac29e55..3d7a6b451e2 100644
--- a/packages/core/test/Serialization/Certificates/PoolParams/PoolParams.test.ts
+++ b/packages/core/test/Serialization/Certificates/PoolParams/PoolParams.test.ts
@@ -52,6 +52,7 @@ describe('PoolParams', () => {
     expect(
       params
         .poolOwners()
+        .toCore()
         .map((keyHash) => Cardano.createRewardAccount(keyHash, params.rewardAccount().toAddress().getNetworkId()))
     ).toEqual([Cardano.RewardAccount('stake1u89sasnfyjtmgk8ydqfv3fdl52f36x3djedfnzfc9rkgzrcss5vgr')]);
     expect(params.relays().map((relay) => relay.toCore())).toEqual([
@@ -87,6 +88,7 @@ describe('PoolParams', () => {
     expect(
       params
         .poolOwners()
+        .toCore()
         .map((keyHash) => Cardano.createRewardAccount(keyHash, params.rewardAccount().toAddress().getNetworkId()))
     ).toEqual([Cardano.RewardAccount('stake1u89sasnfyjtmgk8ydqfv3fdl52f36x3djedfnzfc9rkgzrcss5vgr')]);
     expect(params.relays().map((relay) => relay.toCore())).toEqual([
diff --git a/packages/core/test/Serialization/Certificates/PoolRegistration.test.ts b/packages/core/test/Serialization/Certificates/PoolRegistration.test.ts
index 89a2e5e680c..481720815a0 100644
--- a/packages/core/test/Serialization/Certificates/PoolRegistration.test.ts
+++ b/packages/core/test/Serialization/Certificates/PoolRegistration.test.ts
@@ -8,6 +8,10 @@ const cbor = HexBlob(
   '8a03581cd85087c646951407198c27b1b950fd2e99f28586c000ce39f6e6ef9258208dd154228946bd12967c12bedb1cb6038b78f8b84a1760b1a788fa72a4af3db01927101903e8d81e820105581de1cb0ec2692497b458e46812c8a5bfa2931d1a2d965a99893828ec810f81581ccb0ec2692497b458e46812c8a5bfa2931d1a2d965a99893828ec810f8383011913886b6578616d706c652e636f6d8400191770447f000001f682026b6578616d706c652e636f6d827368747470733a2f2f6578616d706c652e636f6d58200f3abbc8fc19c2e61bab6059bf8a466e6e754833a08a62a6c56fe0e78f19d9d5'
 );
 
+const cborWithSets = HexBlob(
+  '8a03581cd85087c646951407198c27b1b950fd2e99f28586c000ce39f6e6ef9258208dd154228946bd12967c12bedb1cb6038b78f8b84a1760b1a788fa72a4af3db01927101903e8d81e820105581de1cb0ec2692497b458e46812c8a5bfa2931d1a2d965a99893828ec810fd9010281581ccb0ec2692497b458e46812c8a5bfa2931d1a2d965a99893828ec810f8383011913886b6578616d706c652e636f6d8400191770447f000001f682026b6578616d706c652e636f6d827368747470733a2f2f6578616d706c652e636f6d58200f3abbc8fc19c2e61bab6059bf8a466e6e754833a08a62a6c56fe0e78f19d9d5'
+);
+
 const poolParameters: Cardano.PoolParameters = {
   cost: 1000n,
   id: Cardano.PoolId('pool1mpgg03jxj52qwxvvy7cmj58a96vl9pvxcqqvuw0kumheygxmn34'),
@@ -57,6 +61,7 @@ describe('PoolRegistration', () => {
     expect(
       params
         .poolOwners()
+        .toCore()
         .map((keyHash) => Cardano.createRewardAccount(keyHash, params.rewardAccount().toAddress().getNetworkId()))
     ).toEqual([Cardano.RewardAccount('stake1u89sasnfyjtmgk8ydqfv3fdl52f36x3djedfnzfc9rkgzrcss5vgr')]);
     expect(params.relays().map((relay) => relay.toCore())).toEqual([
@@ -93,6 +98,7 @@ describe('PoolRegistration', () => {
     expect(
       params
         .poolOwners()
+        .toCore()
         .map((keyHash) => Cardano.createRewardAccount(keyHash, params.rewardAccount().toAddress().getNetworkId()))
     ).toEqual([Cardano.RewardAccount('stake1u89sasnfyjtmgk8ydqfv3fdl52f36x3djedfnzfc9rkgzrcss5vgr')]);
     expect(params.relays().map((relay) => relay.toCore())).toEqual([
@@ -121,4 +127,9 @@ describe('PoolRegistration', () => {
 
     expect(certificate.toCore()).toEqual(core);
   });
+
+  it('can encode PoolRegistration with 6.248 tags to Core', () => {
+    const certificate = PoolRegistration.fromCbor(cborWithSets);
+    expect(certificate.toCore()).toEqual(core);
+  });
 });
diff --git a/packages/core/test/Serialization/Common/Credential.test.ts b/packages/core/test/Serialization/Common/Credential.test.ts
new file mode 100644
index 00000000000..c8e1bfe92a5
--- /dev/null
+++ b/packages/core/test/Serialization/Common/Credential.test.ts
@@ -0,0 +1,28 @@
+import * as Crypto from '@cardano-sdk/crypto';
+import { HexBlob } from '@cardano-sdk/util';
+
+import { Cardano } from '../../../src';
+import { Credential } from '../../../src/Serialization/Common';
+
+describe('Credential', () => {
+  const cbor = HexBlob('8200581c30000000000000000000000000000000000000000000000000000000');
+  const cborArraySize3 = HexBlob('8300581c3000000000000000000000000000000000000000000000000000000000');
+  const coreCredential: Cardano.Credential = {
+    hash: Crypto.Hash28ByteBase16('30000000000000000000000000000000000000000000000000000000'),
+    type: Cardano.CredentialType.KeyHash
+  };
+
+  it('can encode init from Core', () => {
+    const credential = Credential.fromCore(coreCredential);
+    expect(credential.toCbor()).toEqual(cbor);
+  });
+
+  it('can encode to Core', () => {
+    const credential = Credential.fromCbor(cbor);
+    expect(credential.toCore()).toEqual(coreCredential);
+  });
+
+  it('politely refuses an invalid credential cbor', () => {
+    expect(() => Credential.fromCbor(cborArraySize3)).toThrow();
+  });
+});
diff --git a/packages/core/test/Serialization/Transaction.test.ts b/packages/core/test/Serialization/Transaction.test.ts
index 2401e93bfbc..473a7a3d887 100644
--- a/packages/core/test/Serialization/Transaction.test.ts
+++ b/packages/core/test/Serialization/Transaction.test.ts
@@ -28,7 +28,7 @@ describe('Transaction', () => {
     expect(tx.body()).toBeInstanceOf(TransactionBody);
     const witnessSet = tx.witnessSet();
     const vKeys = witnessSet.vkeys();
-    const witness = vKeys![0];
+    const witness = vKeys!.values()[0];
     const witnessSignature = witness.signature();
     const vKey = witness.vkey();
     expect(vKey).toBe(vkey);
diff --git a/packages/core/test/Serialization/TransactionBody/ProposalProcedure/UpdateCommittee.test.ts b/packages/core/test/Serialization/TransactionBody/ProposalProcedure/UpdateCommittee.test.ts
index 40185970c83..b7d3ddb8255 100644
--- a/packages/core/test/Serialization/TransactionBody/ProposalProcedure/UpdateCommittee.test.ts
+++ b/packages/core/test/Serialization/TransactionBody/ProposalProcedure/UpdateCommittee.test.ts
@@ -8,6 +8,10 @@ const cbor = HexBlob(
   '8504825820000000000000000000000000000000000000000000000000000000000000000003828200581c000000000000000000000000000000000000000000000000000000008200581c20000000000000000000000000000000000000000000000000000000a28200581c30000000000000000000000000000000000000000000000000000000018200581c4000000000000000000000000000000000000000000000000000000002d81e820105'
 );
 
+const cborWithConwaySet = HexBlob(
+  '8504825820000000000000000000000000000000000000000000000000000000000000000003d90102828200581c000000000000000000000000000000000000000000000000000000008200581c20000000000000000000000000000000000000000000000000000000a28200581c30000000000000000000000000000000000000000000000000000000018200581c4000000000000000000000000000000000000000000000000000000002d81e820105'
+);
+
 const core = {
   __typename: Cardano.GovernanceActionType.update_committee,
   governanceActionId: { actionIndex: 3, id: '0000000000000000000000000000000000000000000000000000000000000000' },
@@ -52,4 +56,9 @@ describe('UpdateCommittee', () => {
 
     expect(action.toCore()).toEqual(core);
   });
+
+  it('can encode UpdateCommittee with 6.248 tags to Core', () => {
+    const body = UpdateCommittee.fromCbor(cborWithConwaySet);
+    expect(body.toCore()).toEqual(core);
+  });
 });
diff --git a/packages/core/test/Serialization/TransactionBody/TransactionBody.test.ts b/packages/core/test/Serialization/TransactionBody/TransactionBody.test.ts
index 045e504ec1a..db5725e1c53 100644
--- a/packages/core/test/Serialization/TransactionBody/TransactionBody.test.ts
+++ b/packages/core/test/Serialization/TransactionBody/TransactionBody.test.ts
@@ -15,6 +15,10 @@ const conwayCbor = HexBlob(
   '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'
 );
 
+const conwayCborWithSets = HexBlob(
+  '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'
+);
+
 export const core: Cardano.TxBody = {
   auxiliaryDataHash: Crypto.Hash32ByteBase16('2ceb364d93225b4a0f004a0975a13eb50c3cc6348474b4fe9121f8dc72ca0cfa'),
   certificates: [
@@ -246,6 +250,11 @@ describe('TransactionBody', () => {
     expect(body.toCore()).toEqual(expectedConwayCore);
   });
 
+  it('can encode TransactionBody with 6.248 tags to Core', () => {
+    const body = TransactionBody.fromCbor(conwayCborWithSets);
+    expect(body.toCore()).toEqual(expectedConwayCore);
+  });
+
   it('sorts withdrawals canonically', () => {
     const body = TransactionBody.fromCbor(cbor);
     const withdrawals = body.withdrawals();
diff --git a/packages/core/test/Serialization/TransactionWitnessSet/TransactionWitnessSet.test.ts b/packages/core/test/Serialization/TransactionWitnessSet/TransactionWitnessSet.test.ts
index c3b6bc1e4cc..d44c4310653 100644
--- a/packages/core/test/Serialization/TransactionWitnessSet/TransactionWitnessSet.test.ts
+++ b/packages/core/test/Serialization/TransactionWitnessSet/TransactionWitnessSet.test.ts
@@ -10,6 +10,10 @@ const cbor = HexBlob(
   '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'
 );
 
+const cborWithSets = HexBlob(
+  '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'
+);
+
 const simpleWitnessCbor = HexBlob(
   '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'
 );
@@ -195,6 +199,11 @@ describe('TransactionWitnessSet', () => {
     expect(witness.toCore()).toEqual(core);
   });
 
+  it('can encode TransactionWitnessSet with 6.248 tags to Core', () => {
+    const witness = TransactionWitnessSet.fromCbor(cborWithSets);
+    expect(witness.toCore()).toEqual(core);
+  });
+
   it('can encode simple TransactionWitnessSet to CBOR', () => {
     const witness = TransactionWitnessSet.fromCore(simpleCore);
     expect(witness.toCbor()).toEqual(simpleWitnessCbor);
diff --git a/packages/web-extension/src/walletManager/util.ts b/packages/web-extension/src/walletManager/util.ts
index ab70ae1df3b..efee2940dba 100644
--- a/packages/web-extension/src/walletManager/util.ts
+++ b/packages/web-extension/src/walletManager/util.ts
@@ -161,7 +161,7 @@ const requiresStakingWitness = (
     networkId
   );
   const withdrawals = body.withdrawals() ?? new Map();
-  const certificates = (body.certs() ?? []).map((certificate) => certificate.toCore());
+  const certificates = (body.certs()?.values() ?? []).map((certificate) => certificate.toCore());
 
   if (withdrawals.size > 0 && withdrawals.has((key: Cardano.RewardAccount) => key === rewardAccount)) return true;