Fix isHexString validation

elements/lisk-validator/src/validation.ts

@@ -74,7 +74,7 @@ export const isHexString = (data: unknown): boolean => {
 		return false;
 	}
 
-	return data === '' || /^[a-f0-9]+$/i.test(data);
+	return data === '' || /^([0-9a-f]{2})+$/i.test(data);
 };
 
 export const isEncryptedPassphrase = (data: string): boolean => {

elements/lisk-validator/test/validation.spec.ts

@@ -78,8 +78,11 @@ describe('validation', () => {
 
 	describe('#isHexString', () => {
 		it('should return true when valid hex was provided', () => {
-			return expect(
-				isHexString('215b667a32a5cd51a94c9c2046c11fffb08c65748febec099451e3b164452bc'),
+			expect(
+				isHexString('215b667a32a5cd51a94c9c2046c11fffb08c65748febec099451e3b164452b'),
+			).toBeTrue();
+			expect(
+				isHexString('215B667A32a5cd51A94c9c2046c11fffb08c65748febec099451e3b164452B'),
 			).toBeTrue();
 		});
 
@@ -92,6 +95,14 @@ describe('validation', () => {
 				isHexString('zzzzzzza32a5cd51a94c9c2046c11fffb08c65748febec099451e3b164452bc'),
 			).toBeFalse();
 		});
+
+		it('should return true when input is empty', () => {
+			return expect(isHexString('')).toBeTrue();
+		});
+
+		it('should return false when input length is odd', () => {
+			return expect(isHexString('ff1')).toBeFalse();
+		});
 	});
 
 	describe('#isEncryptedPassphrase', () => {