Improve code quality and add decrypt status return value

tests/decrypt.test.ts

@@ -1,21 +1,44 @@
 import { decrypt } from '../src/decrypt'
 
-test('Test buffers are supported by decrypt function.', () => {
+test('Test nonce parsing by public decrypt function.', () => {
   // Given
   const ciphertext = Buffer.from([
+    // Nonce
+    0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
+    // Ciphertext
     225, 53, 3, 212, 22, 112, 246, 194, 61, 171, 230, 187, 157, 102, 32, 76, 62, 65,
     25, 202, 255, 201, 206, 49, 60, 58, 82, 216, 72, 116, 106, 129, 162, 142, 69, 40,
     167, 88, 94, 195, 174, 217, 242, 149, 224, 125, 196, 237, 172, 165, 116, 119, 128
   ])
   const associatedData = Buffer.from('Some associated data.')
-  const nonce = Buffer.from('\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f')
   const key = Buffer.from('\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f')
 
   // When
-  const result = decrypt(ciphertext, associatedData, nonce, key)
+  const result = decrypt(ciphertext, associatedData, key)
 
   // Then
   const expectedResult = Buffer.from('Hello, World! This is a test message.')
-
-  expect(result).toMatchObject(expectedResult)
+  expect(result.success).toBe(true)
+  expect(result.plaintext).toMatchObject(expectedResult)
+})
+
+test('Test decryption with an invalid key.', () => {
+  // Given
+  const ciphertext = Buffer.from([
+    // Nonce
+    0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
+    // Ciphertext
+    225, 53, 3, 212, 22, 112, 246, 194, 61, 171, 230, 187, 157, 102, 32, 76, 62, 65,
+    25, 202, 255, 201, 206, 49, 60, 58, 82, 216, 72, 116, 106, 129, 162, 142, 69, 40,
+    167, 88, 94, 195, 174, 217, 242, 149, 224, 125, 196, 237, 172, 165, 116, 119, 128
+  ])
+  const associatedData = Buffer.from('Some associated data.')
+  const key = Buffer.from('\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f\x00')
+
+  // When
+  const result = decrypt(ciphertext, associatedData, key)
+
+  // Then
+  expect(result.success).toBe(false)
+  expect(result.plaintext).toMatchObject(Buffer.alloc(0))
 })

tests/encrypt.test.ts

@@ -1,20 +1,17 @@
+import { decrypt } from '../src/decrypt'
 import { encrypt } from '../src/encrypt'
 
-test('Test buffers are supported by encrypt function.', () => {
+test('Test nonce generation by public encrypt function.', () => {
   // Given
   const message = Buffer.from('Hello, World! This is a test message.')
   const associatedData = Buffer.from('Some associated data.')
-  const nonce = Buffer.from('\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f')
   const key = Buffer.from('\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f')
 
   // When
-  const result = encrypt(message, associatedData, nonce, key)
+  const ciphertext = encrypt(message, associatedData, key)
+  const plaintext = decrypt(ciphertext, associatedData, key)
 
   // Then
-  const expectedResult = Buffer.from([
-    225, 53, 3, 212, 22, 112, 246, 194, 61, 171, 230, 187, 157, 102, 32, 76, 62, 65,
-    25, 202, 255, 201, 206, 49, 60, 58, 82, 216, 72, 116, 106, 129, 162, 142, 69, 40,
-    167, 88, 94, 195, 174, 217, 242, 149, 224, 125, 196, 237, 172, 165, 116, 119, 128
-  ])
-  expect(result).toMatchObject(expectedResult)
+  expect(plaintext.success).toBe(true)
+  expect(plaintext.plaintext).toMatchObject(message)
 })

tests/romulus-m-reference.test.ts

@@ -1,5 +1,5 @@
 import { referenceTests } from './resources/reference-tests'
-import { cryptoAeadDecrypt, cryptoAeadEncrypt } from '../src/romulus-m'
+import { cryptoAeadDecrypt, cryptoAeadEncrypt, DecryptResult } from '../src/romulus-m'
 
 function parseHexString (string: string): number[] {
   const ret = []
@@ -24,6 +24,9 @@ test.each(referenceTests)('Perform decryption using reference test %#.', (key, n
   const result = cryptoAeadDecrypt(parseHexString(ciphertext), parseHexString(associatedData), parseHexString(nonce), parseHexString(key))
 
   // Then
-  const expectedResult = parseHexString(plaintext)
+  const expectedResult: DecryptResult = {
+    success: true,
+    plaintext: parseHexString(plaintext)
+  }
   expect(result).toMatchObject(expectedResult)
 })

tests/romulus-m.test.ts

@@ -59,7 +59,8 @@ test('Decrypt a message with no associated data.', () => {
 
   // Then
   const expectedResult = stringToArray('Hello, World! This is a test message.')
-  expect(result).toMatchObject(expectedResult)
+  expect(result.success).toBe(true)
+  expect(result.plaintext).toMatchObject(expectedResult)
 })
 
 test('Decrypt a message with associated data.', () => {
@@ -78,5 +79,6 @@ test('Decrypt a message with associated data.', () => {
 
   // Then
   const expectedResult = stringToArray('Hello, World! This is a test message.')
-  expect(result).toMatchObject(expectedResult)
+  expect(result.success).toBe(true)
+  expect(result.plaintext).toMatchObject(expectedResult)
 })