feat: add checksum utils for address (#3308)

* feat: add checksum for address

* chore: add changesets

* Update .changeset/hip-files-protect.md

* chore: release PR

* unrelease PR

---------

Co-authored-by: Peter Smith <peter@blueoceancomputing.co.uk>
Co-authored-by: Sérgio Torres <30977845+Torres-ssf@users.noreply.github.com>

.changeset/hip-files-protect.md

@@ -0,0 +1,6 @@
+---
+"@fuel-ts/interfaces": patch
+"@fuel-ts/address": patch
+---
+
+feat: add checksum utils for address

packages/address/src/address.test.ts

@@ -377,4 +377,25 @@ describe('Address class', () => {
     );
     await expectToThrowFuelError(() => Address.fromEvmAddress(address), expectedError);
   });
+
+  test('validate checksum address', () => {
+    const address = Address.fromRandom();
+    const addressMock = '0x9cFB2Cad509d417eC40B70eBe1DD72a3624d46fDD1EA5420DbD755Ce7f4dC897';
+    expect(Address.isChecksumValid(address.toChecksum())).toBeTruthy();
+    expect(Address.fromB256(addressMock).toChecksum()).toBe(addressMock);
+    expect(Address.isChecksumValid(addressMock)).toBeTruthy();
+    expect(Address.isChecksumValid(addressMock.slice(2))).toBeTruthy();
+  });
+
+  test('validate checksum address for invalid types', () => {
+    const address = Address.fromRandom();
+    expect(Address.isChecksumValid(address.toB256())).toBeFalsy();
+    expect(
+      Address.isChecksumValid('0x9cFB2Cad509d417eC40B70eBe1DD72a3624d46fDD1EA5420DbD755Ce7f4dc897')
+    ).toBeFalsy();
+    expect(
+      Address.isChecksumValid('9cFB2Cad509d417eC40B70eBe1DD72a3624d46fDD1EA5420DbD755Ce7f4dc897')
+    ).toBeFalsy();
+    expect(Address.isChecksumValid('9cFB2Cad509d417eC40B70eBe1DD72')).toBeFalsy();
+  });
 });

packages/address/src/address.ts

@@ -1,6 +1,12 @@
 import { FuelError } from '@fuel-ts/errors';
 import { AbstractAddress } from '@fuel-ts/interfaces';
-import type { Bech32Address, B256Address, EvmAddress, AssetId } from '@fuel-ts/interfaces';
+import type {
+  Bech32Address,
+  B256Address,
+  EvmAddress,
+  AssetId,
+  ChecksumAddress,
+} from '@fuel-ts/interfaces';
 import { arrayify, hexlify } from '@fuel-ts/utils';
 import { sha256 } from '@noble/hashes/sha256';
 
@@ -42,6 +48,16 @@ export default class Address extends AbstractAddress {
     }
   }
 
+  /**
+   * Takes an B256 Address and returns back an checksum address.
+   * The implementation follows the ERC-55 https://github.com/ethereum/ercs/blob/master/ERCS/erc-55.md.
+   *
+   * @returns A new `ChecksumAddress` instance
+   */
+  toChecksum(): ChecksumAddress {
+    return Address.toChecksum(this.toB256());
+  }
+
   /**
    * Returns the `bech32Address` property
    *
@@ -252,4 +268,39 @@ export default class Address extends AbstractAddress {
 
     return new Address(toBech32(paddedAddress));
   }
+
+  /**
+   * Takes an ChecksumAddress and validates if it is a valid checksum address.
+   *
+   * @returns A `boolean` instance indicating if the address is valid.
+   */
+  static isChecksumValid(address: ChecksumAddress): boolean {
+    let addressParsed = address;
+
+    if (!address.startsWith('0x')) {
+      addressParsed = `0x${address}`;
+    }
+    if (addressParsed.trim().length !== 66) {
+      return false;
+    }
+
+    return Address.toChecksum(hexlify(addressParsed)) === addressParsed;
+  }
+
+  /** @hidden */
+  private static toChecksum(address: string) {
+    const addressHex = hexlify(address).toLowerCase().slice(2);
+    const checksum = sha256(address);
+
+    let ret = '0x';
+    for (let i = 0; i < 32; ++i) {
+      const byte = checksum[i];
+      const ha = addressHex.charAt(i * 2);
+      const hb = addressHex.charAt(i * 2 + 1);
+      ret += (byte & 0xf0) >= 0x80 ? ha.toUpperCase() : ha;
+      ret += (byte & 0x0f) >= 0x08 ? hb.toUpperCase() : hb;
+    }
+
+    return ret;
+  }
 }

packages/interfaces/src/index.ts

@@ -12,6 +12,8 @@ export type Bech32Address = `fuel${string}`;
 // #endregion bech32-1
 export type B256Address = string;
 
+export type ChecksumAddress = string;
+
 export type B256AddressEvm = `0x000000000000000000000000${string}`;
 
 export type Bytes = Uint8Array | number[];