5mYhnwy8

1import java.nio.ByteBuffer
2import java.security.SecureRandom
3import java.util.*
4import javax.crypto.Cipher
5import javax.crypto.spec.GCMParameterSpec
6import javax.crypto.spec.SecretKeySpec
7
8fun main(args: Array<String>) {
9
10    val secureRandom = SecureRandom()
11    val key = ByteArray(16) //DONT REUSE THIS SHIT, NIGGA
12    val secretKey = SecretKeySpec(key, "AES")
13    val initializationVector = ByteArray(12) //DONT REUSE THIS SHIT, ANOTHER NIGGA
14    val cipher = Cipher.getInstance("AES/GCM/NoPadding")
15    val parameterSpec = GCMParameterSpec(128, initializationVector)
16
17    fun printMe(key: ByteArray, tag: String) {
18        print("$tag: [")
19        for (i in 0 until key.size step 1) {
20            print(key[i])
21            if (i < key.size - 1) {
22                print(", ")
23            }
24        }
25        println("]")
26    }
27
28    fun dontReuseNigga() {
29        secureRandom.nextBytes(key)
30        secureRandom.nextBytes(initializationVector)
31    }
32
33    fun decrypt(cipherMessage: ByteArray) {
34        val byteBuffer = ByteBuffer.wrap(cipherMessage)
35        val ivLength = byteBuffer.int
36        if (ivLength < 12 || ivLength >= 16) { // check input parameter
37            throw IllegalArgumentException("invalid iv length")
38        }
39        val initializationVector = ByteArray(ivLength)
40        byteBuffer.get(initializationVector)
41        val cipherText = ByteArray(byteBuffer.remaining())
42        byteBuffer.get(cipherText)
43
44        cipher.init(Cipher.DECRYPT_MODE, secretKey, parameterSpec)
45        val plaintext = cipher.doFinal(cipherText)
46
47        println("[DECRYPTION RESULTS]")
48        println("Ciphertext: (Base64-encoded): " + Base64.getEncoder().encodeToString(cipherMessage))
49        println("Plaintext: " + String(plaintext))
50    }
51
52    fun decrypt(cipherText: String) {
53        decrypt(Base64.getDecoder().decode(cipherText))
54    }
55
56    fun encrypt(plainText: String) {
57        dontReuseNigga() //always initialize before every operation to generate a random seed
58        cipher.init(Cipher.ENCRYPT_MODE, secretKey, parameterSpec)
59        val cipherText = cipher.doFinal(plainText.toByteArray())
60
61        val byteBuffer = ByteBuffer.allocate(4 + initializationVector.size + cipherText.size)
62        byteBuffer.putInt(initializationVector.size)
63        byteBuffer.put(initializationVector)
64        byteBuffer.put(cipherText)
65        val cipherMessage = byteBuffer.array()
66
67        val base64Enc = Base64.getEncoder().encodeToString(cipherMessage)
68
69        //THIS IS ANTIHACKING MEASURES
70        //Clean the key array to remove traces of keys used in the encryption
71        //Do not depend on the GC to do this (its unpredictable when that nigga's gonna go to work)
72        printMe(key, "before")
73        Arrays.fill(key, 0)
74        printMe(key, "after")
75
76        println("[ENCRYPTION RESULTS]")
77        println("Plaintext: $plainText")
78        println("Ciphertext (Base64-encoded): $base64Enc")
79
80        //we saving the base64 encoded ciphertext so i made it possible to feed out decryptor
81        //with String or ByteArray parameters
82        decrypt(base64Enc)
83        decrypt(cipherMessage)
84    }
85
86    encrypt("This is a plaintext")
87
88}