Added verifySignature function in PublicAccount class

src/model/account/PublicAccount.ts

@@ -14,8 +14,9 @@
  * limitations under the License.
  */
 
-import {NetworkType} from '../blockchain/NetworkType';
-import {Address} from './Address';
+import { KeyPair, convert } from 'nem2-library';
+import { NetworkType } from '../blockchain/NetworkType';
+import { Address } from './Address';
 
 /**
  * The public account structure contains account's address and public key.
@@ -53,6 +54,44 @@ export class PublicAccount {
         return new PublicAccount(publicKey, address);
     }
 
+    /**
+     * Verify a signature.
+     *
+     * @param {PublicAccount} publicAccount - The public account to use for verification.
+     * @param {string} data - The data to verify.
+     * @param {string} signature - The signature to verify.
+     *
+     * @return {boolean}  - True if the signature is valid, false otherwise.
+     */
+    static verifySignature(publicAccount: PublicAccount, data: string, signature: string): boolean {
+        if (!publicAccount || !data || !signature) {
+            throw new Error('Missing argument');
+        }
+
+        if (signature.length !== 128) {
+            throw new Error('Signature length is incorrect');
+        }
+
+        if (!convert.isHexString(signature)) {
+            throw new Error('Signature must be hexadecimal only');
+        }
+
+        // Convert signature key to Uint8Array
+        const convertedSignature = convert.hexToUint8(signature);
+
+        let convertedData;
+
+        // Convert data to hex if data is not hex
+        if (!convert.isHexString(data)) {
+            convertedData = convert.utf8ToHex(data);
+        }
+
+        // Convert to Uint8Array
+        convertedData = convert.hexToUint8(convertedData);
+
+        return KeyPair.verify(publicAccount.publicKey, convertedData, convertedSignature);
+    }
+
     /**
      * Compares public accounts for equality.
      * @param publicAccount
@@ -61,4 +100,5 @@ export class PublicAccount {
     equals(publicAccount: PublicAccount) {
         return this.publicKey === publicAccount.publicKey && this.address.plain() === publicAccount.address.plain();
     }
+
 }

test/model/account/PublicAccount.spec.ts

@@ -14,9 +14,9 @@
  * limitations under the License.
  */
 
-import {expect} from 'chai';
-import {PublicAccount} from '../../../src/model/account/PublicAccount';
-import {NetworkType} from '../../../src/model/blockchain/NetworkType';
+import { expect } from 'chai';
+import { PublicAccount } from '../../../src/model/account/PublicAccount';
+import { NetworkType } from '../../../src/model/blockchain/NetworkType';
 
 describe('PublicAccount', () => {
     const publicKey = 'b4f12e7c9f6946091e2cb8b6d3a12b50d17ccbbf646386ea27ce2946a7423dcf';
@@ -27,3 +27,83 @@ describe('PublicAccount', () => {
         expect(publicAccount.address.plain()).to.be.equal('SARNASAS2BIAB6LMFA3FPMGBPGIJGK6IJETM3ZSP');
     });
 });
+
+describe('Signature verification', () => {
+    it('Can verify a signature', () => {
+        // Arrange:'
+        const signerPublicAccount = PublicAccount.createFromPublicKey('22816F825B4CACEA334723D51297D8582332D8B875A5829908AAE85831ABB508',
+            NetworkType.MIJIN_TEST);
+        const data = 'I am so so so awesome as always';
+        const signature = 'B01DCA6484026C2ECDF3C822E64DEAAFC15EBCCE337EEE209C28513CB5351CDED8863A8E7B855CD471B55C91FAE611C548625C9A5916A555A24F72F3526FA508'; // tslint:disable-line
+
+        // Act & Assert:
+        expect(PublicAccount.verifySignature(signerPublicAccount, data, signature)).equal(true);
+    });
+
+    it('Throw error if signature has invalid length', () => {
+        // Arrange:
+        const signerPublicAccount = PublicAccount.createFromPublicKey('22816F825B4CACEA334723D51297D8582332D8B875A5829908AAE85831ABB508',
+            NetworkType.MIJIN_TEST);
+        const data = 'I am so so so awesome as always';
+        const signature = 'B01DCA6484026C2ECDF3C822E64DEAAFC15EBCCE337EEE209C28513CB5351CDED8863A8E7B855CD471B55C91FAE611C5486'; // tslint:disable-line
+
+        // Act & Assert:
+        expect(() => { PublicAccount.verifySignature(signerPublicAccount, data, signature); }).to.throw('Signature length is incorrect');
+    });
+
+    it('Throw error if signature is not strictly hexadecimal', () => {
+        // Arrange:
+        const signerPublicAccount = PublicAccount.createFromPublicKey('22816F825B4CACEA334723D51297D8582332D8B875A5829908AAE85831ABB508',
+            NetworkType.MIJIN_TEST);
+        const data = 'I am so so so awesome as always';
+        const signature = 'B01DCA6484026C2ECDF3C822E64DEAAFC15EBCCE337EEE209C28513CB5351CDED8863A8E7B855CD471B55C91FAE611C548625C9A5916A555A24F72F35a1wwwww';// tslint:disable-line
+
+        // Act & Assert:
+        expect(() => { PublicAccount.verifySignature(signerPublicAccount, data, signature); })
+            .to.throw('Signature must be hexadecimal only');
+    });
+
+    it('Return false if wrong public key provided', () => {
+        // Arrange:
+        const signerPublicAccount = PublicAccount.createFromPublicKey('12816F825B4CACEA334723D51297D8582332D8B875A5829908AAE85831ABB509',
+            NetworkType.MIJIN_TEST);
+        const data = 'I am so so so awesome as always';
+        const signature = 'B01DCA6484026C2ECDF3C822E64DEAAFC15EBCCE337EEE209C28513CB5351CDED8863A8E7B855CD471B55C91FAE611C548625C9A5916A555A24F72F3526FA508';// tslint:disable-line
+
+        // Act & Assert:
+        expect(PublicAccount.verifySignature(signerPublicAccount, data, signature)).equal(false);
+    });
+
+    it('Return false if data is not corresponding to signature provided', () => {
+        // Arrange:
+        const signerPublicAccount = PublicAccount.createFromPublicKey('22816F825B4CACEA334723D51297D8582332D8B875A5829908AAE85831ABB508',
+            NetworkType.MIJIN_TEST);
+        const data = 'I am awesome as always';
+        const signature = 'B01DCA6484026C2ECDF3C822E64DEAAFC15EBCCE337EEE209C28513CB5351CDED8863A8E7B855CD471B55C91FAE611C548625C9A5916A555A24F72F3526FA508';// tslint:disable-line
+
+        // Act & Assert:
+        expect(PublicAccount.verifySignature(signerPublicAccount, data, signature)).equal(false);
+    });
+
+    it('Return false if signature is not corresponding to data provided', () => {
+        // Arrange:
+        const signerPublicAccount = PublicAccount.createFromPublicKey('22816F825B4CACEA334723D51297D8582332D8B875A5829908AAE85831ABB508',
+            NetworkType.MIJIN_TEST);
+        const data = 'I am so so so awesome as always';
+        const signature = 'A01DCA6484026C2ECDF3C822E64DEAAFC15EBCCE337EEE209C28513CB5351CDED8863A8E7B855CD471B55C91FAE611C548625C9A5916A555A24F72F3526FA509';// tslint:disable-line
+
+        // Act & Assert:
+        expect(PublicAccount.verifySignature(signerPublicAccount, data, signature)).equal(false);
+    });
+
+    it('Throw error if signature verification is missing a parameter', () => {
+        // Arrange:
+        const signerPublicAccount = PublicAccount.createFromPublicKey('22816F825B4CACEA334723D51297D8582332D8B875A5829908AAE85831ABB508',
+            NetworkType.MIJIN_TEST);
+        const data = '';
+        const signature = 'B01DCA6484026C2ECDF3C822E64DEAAFC15EBCCE337EEE209C28513CB5351CDED8863A8E7B855CD471B55C91FAE611C548625C9A5916A555A24F72F3526FA508';// tslint:disable-line
+
+        // Act & Assert:
+        expect(() => { PublicAccount.verifySignature(signerPublicAccount, data, signature); }).to.throw('Missing argument');
+    });
+});