39i8bcA6

1package main
2
3import (
4    "fmt"
5    "os"
6
7    "crypto/rand"
8    "golang.org/x/crypto/nacl/secretbox"
9)
10
11func generateRandomBytes(n int) []byte {
12    b := make([]byte, n)
13    _, err := rand.Read(b)
14    if err != nil {
15        fmt.Println(err)
16        os.Exit(1)
17    }
18    return b
19}
20
21func encrypt(plaintext, key []byte) []byte {
22    nonceSlice := generateRandomBytes(24)
23
24    var nonce [24]byte
25    copy(nonce[:], nonceSlice)
26
27    var secretKey [32]byte
28    copy(secretKey[:], key)
29
30    return secretbox.Seal(nonce[:], plaintext, &nonce, &secretKey)
31}
32
33func decrypt(ciphertext, key []byte) []byte {
34    var nonce [24]byte
35    copy(nonce[:], ciphertext[:24])
36
37    var secretKey [32]byte
38    copy(secretKey[:], key)
39
40    plaintext, okay := secretbox.Open([]byte{}, ciphertext[24:], &nonce, &secretKey)
41    if !okay {
42        fmt.Println("decryption failed")
43        os.Exit(1)
44    }
45
46    return plaintext
47}
48
49func main() {
50    key := generateRandomBytes(32)
51
52    plaintext := "toby doesn't appreciate being called mean words"
53    fmt.Println(plaintext)
54
55    ciphertext := encrypt([]byte(plaintext), key)
56    fmt.Println(ciphertext)
57
58    plaintext = string(decrypt(ciphertext, key))
59    fmt.Println(plaintext)
60}