Add symmetric capabilities to DecryptedThing

packages/utils/crypto/src/aes256.ts

@@ -0,0 +1,40 @@
+import { field, fixedArray, variant } from "@dao-xyz/borsh";
+import { PlainKey } from "./key";
+import { compare } from "@peerbit/uint8arrays";
+import { toHexString } from "./utils";
+
+import sodium from "libsodium-wrappers";
+
+@variant(0)
+export class Aes256Key extends PlainKey {
+	@field({ type: fixedArray("u8", 32) })
+	key: Uint8Array;
+
+	constructor(properties: { key: Uint8Array }) {
+		super();
+		if (properties.key.length !== 32) {
+			throw new Error("Expecting key to have length 32");
+		}
+		this.key = properties.key;
+	}
+
+	static async create(): Promise<Aes256Key> {
+		await sodium.ready;
+		const generated = sodium.crypto_secretbox_keygen();
+		const kp = new Aes256Key({
+			key: generated
+		});
+
+		return kp;
+	}
+
+	equals(other: Aes256Key): boolean {
+		if (other instanceof Aes256Key) {
+			return compare(this.key, other.key) === 0;
+		}
+		return false;
+	}
+	toString(): string {
+		return "aes256/" + toHexString(this.key);
+	}
+}

packages/utils/crypto/src/encryption.ts

@@ -5,7 +5,8 @@ import {
 	field,
 	serialize,
 	variant,
-	vec
+	vec,
+	fixedArray
 } from "@dao-xyz/borsh";
 import { equals } from "@peerbit/uint8arrays";
 import { AccessError } from "./errors.js";
@@ -14,6 +15,8 @@ import { X25519Keypair, X25519PublicKey, X25519SecretKey } from "./x25519.js";
 import { Ed25519Keypair, Ed25519PublicKey } from "./ed25519.js";
 import { randomBytes } from "./random.js";
 import { Keychain } from "./keychain.js";
+import { sha256 } from "./hash.js";
+import { Aes256Key } from "./aes256.js";
 
 const NONCE_LENGTH = 24;
 
@@ -27,7 +30,10 @@ export abstract class MaybeEncrypted<T> {
 	}
 
 	decrypt(
-		keyOrKeychain?: Keychain | X25519Keypair
+		keyOrKeychain?:
+			| Keychain
+			| X25519Keypair
+			| Aes256Key /* Comment: The last is added */
 	): Promise<DecryptedThing<T>> | DecryptedThing<T> {
 		throw new Error("Not implemented");
 	}
@@ -45,6 +51,24 @@ export abstract class MaybeEncrypted<T> {
 	abstract get byteLength(): number;
 }
 
+type EncryptAsymmetricParameters = {
+	x25519Keypair: X25519Keypair;
+	receiverPublicKeys: (X25519PublicKey | Ed25519PublicKey)[];
+};
+
+type EncryptSymmetricParameters = { symmetricKey: Uint8Array };
+
+type EncryptReturnValue<Parameters, T> =
+	Parameters extends EncryptSymmetricParameters
+		? EncryptedSymmetricThing<T>
+		: EncryptedThing<T>;
+
+function isEncryptSymmetricParameters(
+	parameters: EncryptSymmetricParameters | EncryptAsymmetricParameters
+): parameters is EncryptSymmetricParameters {
+	return (parameters as EncryptSymmetricParameters).symmetricKey !== undefined;
+}
+
 @variant(0)
 export class DecryptedThing<T> extends MaybeEncrypted<T> {
 	@field({ type: Uint8Array })
@@ -69,50 +93,70 @@ export class DecryptedThing<T> extends MaybeEncrypted<T> {
 		return deserialize(this._data, clazz);
 	}
 
-	async encrypt(
-		x25519Keypair: X25519Keypair,
-		...receiverPublicKeys: (X25519PublicKey | Ed25519PublicKey)[]
-	): Promise<EncryptedThing<T>> {
+	async encrypt<
+		Parameters extends EncryptAsymmetricParameters | EncryptSymmetricParameters
+	>(
+		parameters: Parameters
+		/* Comment: instead of 
+        x25519Keypair: X25519Keypair,
+		...receiverPublicKeys: (X25519PublicKey | Ed25519PublicKey)[] */
+	): Promise<
+		EncryptReturnValue<Parameters, T>
+	> /* Comment: instead of Promise<EncryptedThing<T>> */ {
 		const bytes = serialize(this);
-		const epheremalKey = sodium.crypto_secretbox_keygen();
+		const epheremalKey = isEncryptSymmetricParameters(parameters)
+			? parameters.symmetricKey
+			: sodium.crypto_secretbox_keygen();
+		/* Comment: instead of const epheremalKey = sodium.crypto_secretbox_keygen(); */
 		const nonce = randomBytes(NONCE_LENGTH); // crypto random is faster than sodim random
 		const cipher = sodium.crypto_secretbox_easy(bytes, nonce, epheremalKey);
 
-		const receiverX25519PublicKeys = await Promise.all(
-			receiverPublicKeys.map((key) => {
-				if (key instanceof Ed25519PublicKey) {
-					return X25519PublicKey.from(key);
-				}
-				return key;
-			})
-		);
+		if (!isEncryptSymmetricParameters(parameters)) {
+			const { receiverPublicKeys, x25519Keypair } = parameters;
+			const receiverX25519PublicKeys = await Promise.all(
+				receiverPublicKeys.map((key) => {
+					if (key instanceof Ed25519PublicKey) {
+						return X25519PublicKey.from(key);
+					}
+					return key;
+				})
+			);
 
-		const ks = receiverX25519PublicKeys.map((receiverPublicKey) => {
-			const kNonce = randomBytes(NONCE_LENGTH); // crypto random is faster than sodium random
-			return new K({
-				encryptedKey: new CipherWithNonce({
-					cipher: sodium.crypto_box_easy(
-						epheremalKey,
-						kNonce,
-						receiverPublicKey.publicKey,
-						x25519Keypair.secretKey.secretKey
-					),
-					nonce: kNonce
-				}),
-				receiverPublicKey
+			const ks = receiverX25519PublicKeys.map((receiverPublicKey) => {
+				const kNonce = randomBytes(NONCE_LENGTH); // crypto random is faster than sodium random
+				return new K({
+					encryptedKey: new CipherWithNonce({
+						cipher: sodium.crypto_box_easy(
+							epheremalKey,
+							kNonce,
+							receiverPublicKey.publicKey,
+							x25519Keypair.secretKey.secretKey
+						),
+						nonce: kNonce
+					}),
+					receiverPublicKey
+				});
 			});
-		});
-
-		const enc = new EncryptedThing<T>({
+			const enc = new EncryptedThing<T>({
+				encrypted: new Uint8Array(cipher),
+				nonce,
+				envelope: new PublicKeyEnvelope({
+					senderPublicKey: x25519Keypair.publicKey,
+					ks
+				})
+			});
+			enc._decrypted = this;
+			return enc as EncryptReturnValue<Parameters, T>;
+		}
+		const enc = new EncryptedSymmetricThing<T>({
 			encrypted: new Uint8Array(cipher),
 			nonce,
-			envelope: new Envelope({
-				senderPublicKey: x25519Keypair.publicKey,
-				ks
+			envelope: new HashedKeyEnvelope({
+				hash: await sha256(parameters.symmetricKey)
 			})
 		});
 		enc._decrypted = this;
-		return enc;
+		return enc as EncryptReturnValue<Parameters, T>;
 	}
 
 	get decrypted(): DecryptedThing<T> {
@@ -196,23 +240,27 @@ export class K {
 	}
 }
 
+abstract class AbstractEnvelope {}
+
 @variant(0)
-export class Envelope {
+class PublicKeyEnvelope extends AbstractEnvelope {
 	@field({ type: X25519PublicKey })
 	_senderPublicKey: X25519PublicKey;
 
 	@field({ type: vec(K) })
 	_ks: K[];
 
 	constructor(props?: { senderPublicKey: X25519PublicKey; ks: K[] }) {
+		super();
 		if (props) {
 			this._senderPublicKey = props.senderPublicKey;
 			this._ks = props.ks;
 		}
 	}
 
-	equals(other: Envelope): boolean {
-		if (other instanceof Envelope) {
+	// TODO: should this be comparable to AbstractEnvelope?
+	equals(other: PublicKeyEnvelope): boolean {
+		if (other instanceof PublicKeyEnvelope) {
 			if (!this._senderPublicKey.equals(other._senderPublicKey)) {
 				return false;
 			}
@@ -232,6 +280,31 @@ export class Envelope {
 	}
 }
 
+@variant(1)
+class HashedKeyEnvelope extends AbstractEnvelope {
+	@field({ type: fixedArray("u8", 32) })
+	hash: Uint8Array;
+	// TODO: Do we need a salt here?
+	constructor(props?: { hash: Uint8Array }) {
+		super();
+		if (props) {
+			this.hash = props.hash;
+		}
+	}
+
+	// TODO: should this be comparable to AbstractEnvelope?
+	equals(other: HashedKeyEnvelope): boolean {
+		if (other instanceof HashedKeyEnvelope) {
+			if (!equals(this.hash, other.hash)) {
+				return false;
+			}
+			return true;
+		} else {
+			return false;
+		}
+	}
+}
+
 @variant(1)
 export class EncryptedThing<T> extends MaybeEncrypted<T> {
 	@field({ type: Uint8Array })
@@ -240,13 +313,13 @@ export class EncryptedThing<T> extends MaybeEncrypted<T> {
 	@field({ type: Uint8Array })
 	_nonce: Uint8Array;
 
-	@field({ type: Envelope })
-	_envelope: Envelope;
+	@field({ type: PublicKeyEnvelope })
+	_envelope: PublicKeyEnvelope;
 
 	constructor(props?: {
 		encrypted: Uint8Array;
 		nonce: Uint8Array;
-		envelope: Envelope;
+		envelope: PublicKeyEnvelope;
 	}) {
 		super();
 		if (props) {
@@ -374,3 +447,92 @@ export class EncryptedThing<T> extends MaybeEncrypted<T> {
 		return this._encrypted.byteLength; // ignore other metdata for now in the size calculation
 	}
 }
+
+@variant(2)
+export class EncryptedSymmetricThing<T> extends MaybeEncrypted<T> {
+	@field({ type: Uint8Array })
+	_encrypted: Uint8Array;
+
+	@field({ type: Uint8Array })
+	_nonce: Uint8Array;
+
+	@field({ type: HashedKeyEnvelope })
+	_envelope: HashedKeyEnvelope;
+
+	constructor(props?: {
+		encrypted: Uint8Array;
+		nonce: Uint8Array;
+		envelope: HashedKeyEnvelope;
+	}) {
+		super();
+		if (props) {
+			this._encrypted = props.encrypted;
+			this._nonce = props.nonce;
+			this._envelope = props.envelope;
+		}
+	}
+
+	_decrypted?: DecryptedThing<T>;
+	get decrypted(): DecryptedThing<T> {
+		if (!this._decrypted) {
+			throw new Error(
+				"Entry has not been decrypted, invoke decrypt method before"
+			);
+		}
+		return this._decrypted;
+	}
+
+	async decrypt(
+		keyResolver?: Aes256Key /* Comment: instead of Keychain | X25519Keypair */
+	): Promise<DecryptedThing<T>> {
+		if (this._decrypted) {
+			return this._decrypted;
+		}
+
+		if (!keyResolver) {
+			throw new AccessError("Expecting key resolver");
+		}
+
+		/* Comment: Should we add a test for the question "Can we decrypt?" */
+
+		const der = deserialize(
+			sodium.crypto_secretbox_open_easy(
+				this._encrypted,
+				this._nonce,
+				keyResolver.bytes /* Comment: instead of epheremalKey */
+			),
+			DecryptedThing
+		);
+		this._decrypted = der as DecryptedThing<T>;
+		/* } else {
+			throw new AccessError('Failed to resolve decryption key');
+		} */
+		return this._decrypted;
+	}
+
+	equals(other: MaybeEncrypted<T>): boolean {
+		if (other instanceof EncryptedSymmetricThing) {
+			if (!equals(this._encrypted, other._encrypted)) {
+				return false;
+			}
+			if (!equals(this._nonce, other._nonce)) {
+				return false;
+			}
+
+			if (!this._envelope.equals(other._envelope)) {
+				return false;
+			}
+			return true;
+		} else {
+			return false;
+		}
+	}
+
+	clear() {
+		this._decrypted = undefined;
+	}
+
+	get byteLength() {
+		return this._encrypted.byteLength; // ignore other metdata for now in the size calculation
+	}
+}