AmsvMuEz

1import java.security.SecureRandom
2import java.util.Base64
3
4import javax.crypto.spec.{GCMParameterSpec, SecretKeySpec}
5import javax.crypto.{Cipher, KeyGenerator, SecretKey}
6
7object Cryptor {
8
9  def main(args: Array[String]): Unit = {
10    val cryptor = new Cryptor("84AmEdqF7YTruR2o4^2BfwkSA0weHtEVgHz$7Rqy".getBytes)
11
12    val messageToEncrypt = "🤐 Secret message 🤐"
13
14    val encryptedText = cryptor.encrypt(messageToEncrypt)
15    System.out.println("Encrypted Text1: " + encryptedText)
16    val decryptedText = cryptor.decrypt(encryptedText)
17    System.out.println("Decrypted text: " + decryptedText)
18  }
19}
20
21class Cryptor(private val secret: Array[Byte]) {
22
23  private val AES_KEY_SIZE = 256
24  private val AES_KEY_SIZE_IN_BYTE = AES_KEY_SIZE / 8
25  private val IV_SIZE = 128
26  private val TAG_BIT_LENGTH = 128
27  private val ALGO_TRANSFORMATION_STRING = "AES/GCM/PKCS5Padding"
28  private val ALGO = "AES"
29
30  private val secureRandom = new SecureRandom()
31
32  def encrypt(message: String): String = {
33    val aesKey: SecretKey = generateAesKey()
34    val gcmParameterSpec = generateGcmParameterSpec()
35
36    val cipher = Cipher.getInstance(ALGO_TRANSFORMATION_STRING)
37    cipher.init(Cipher.ENCRYPT_MODE, aesKey, gcmParameterSpec, new SecureRandom())
38    cipher.updateAAD(secret)
39
40    val encryptedMessage = cipher.doFinal(message.getBytes)
41    encodeData(aesKey, gcmParameterSpec, encryptedMessage)
42  }
43
44  def decrypt(encryptedDataString: String): String = {
45    val (aesKey, gcmParameterSpec, encryptedMessage) = decodeData(encryptedDataString)
46
47    val cipher = Cipher.getInstance(ALGO_TRANSFORMATION_STRING)
48    cipher.init(Cipher.DECRYPT_MODE, aesKey, gcmParameterSpec, new SecureRandom())
49    cipher.updateAAD(secret)
50
51    val message = cipher.doFinal(encryptedMessage)
52    new String(message)
53  }
54
55  private def generateAesKey(): SecretKey = {
56    val keygen = KeyGenerator.getInstance(ALGO)
57    keygen.init(AES_KEY_SIZE)
58    keygen.generateKey
59  }
60
61  private def generateGcmParameterSpec(): GCMParameterSpec = {
62    val iv = new Array[Byte](IV_SIZE)
63    secureRandom.nextBytes(iv)
64    new GCMParameterSpec(TAG_BIT_LENGTH, iv)
65  }
66
67  private def encodeData(aesKey: SecretKey, gcmParameterSpec: GCMParameterSpec, encryptedMessage: Array[Byte]): String = {
68    val data = aesKey.getEncoded ++ gcmParameterSpec.getIV ++ encryptedMessage
69    Base64.getEncoder.encodeToString(data)
70  }
71
72  private def decodeData(encodedData: String): (SecretKeySpec, GCMParameterSpec, Array[Byte]) = {
73    val data = Base64.getDecoder.decode(encodedData)
74    val aesKey = new SecretKeySpec(data.take(AES_KEY_SIZE_IN_BYTE), ALGO)
75    val iv = data.slice(AES_KEY_SIZE_IN_BYTE, AES_KEY_SIZE_IN_BYTE + IV_SIZE)
76    val gcmParameterSpec =  new GCMParameterSpec(TAG_BIT_LENGTH, iv)
77    val encryptedMessage = data.drop(AES_KEY_SIZE_IN_BYTE + IV_SIZE)
78    (aesKey, gcmParameterSpec, encryptedMessage)
79  }
80}