Commit 74f41102fa4459906386b25da03c10a5c200211f
0 parents
Exists in
master
first commit
Showing
2 changed files
with
71 additions
and
0 deletions
Show diff stats
README.md
| File was created | 1 | ### Link to the original source: [Advanced encryption and decryption](https://astaxie.gitbooks.io/build-web-application-with-golang/content/en/09.6.html) | |
| 2 |
main.go
| File was created | 1 | package aes | |
| 2 | |||
| 3 | import ( | ||
| 4 | "crypto/aes" | ||
| 5 | "crypto/cipher" | ||
| 6 | "crypto/rand" | ||
| 7 | "errors" | ||
| 8 | "io" | ||
| 9 | mrand "math/rand" | ||
| 10 | "time" | ||
| 11 | ) | ||
| 12 | |||
| 13 | const ( | ||
| 14 | keySize = 32 | ||
| 15 | allowedRunes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789" | ||
| 16 | ) | ||
| 17 | |||
| 18 | // RandomKey returns a randomly generated 32 bytes long hex encoded key. | ||
| 19 | func RandomKey() (key []byte) { | ||
| 20 | mrand.Seed(time.Now().UnixNano()) | ||
| 21 | |||
| 22 | key = make([]byte, keySize) | ||
| 23 | |||
| 24 | for i := range key { | ||
| 25 | key[i] = allowedRunes[mrand.Intn(len(allowedRunes))] | ||
| 26 | } | ||
| 27 | |||
| 28 | return key | ||
| 29 | } | ||
| 30 | |||
| 31 | // Encrypt encrypts plaintext with key and returns resulting bytes. | ||
| 32 | func Encrypt(plaintext []byte, key []byte) ([]byte, error) { | ||
| 33 | c, err := aes.NewCipher(key) | ||
| 34 | if err != nil { | ||
| 35 | return nil, err | ||
| 36 | } | ||
| 37 | |||
| 38 | gcm, err := cipher.NewGCM(c) | ||
| 39 | if err != nil { | ||
| 40 | return nil, err | ||
| 41 | } | ||
| 42 | |||
| 43 | nonce := make([]byte, gcm.NonceSize()) | ||
| 44 | if _, err = io.ReadFull(rand.Reader, nonce); err != nil { | ||
| 45 | return nil, err | ||
| 46 | } | ||
| 47 | |||
| 48 | return gcm.Seal(nonce, nonce, plaintext, nil), nil | ||
| 49 | } | ||
| 50 | |||
| 51 | // Decrypt decrypts ciphertext with key and returns resulting bytes. | ||
| 52 | func Decrypt(ciphertext []byte, key []byte) ([]byte, error) { | ||
| 53 | c, err := aes.NewCipher(key) | ||
| 54 | if err != nil { | ||
| 55 | return nil, err | ||
| 56 | } | ||
| 57 | |||
| 58 | gcm, err := cipher.NewGCM(c) | ||
| 59 | if err != nil { | ||
| 60 | return nil, err | ||
| 61 | } | ||
| 62 | |||
| 63 | nonceSize := gcm.NonceSize() | ||
| 64 | if len(ciphertext) < nonceSize { | ||
| 65 | return nil, errors.New("ciphertext too short") | ||
| 66 | } | ||
| 67 | |||
| 68 | nonce, ciphertext := ciphertext[:nonceSize], ciphertext[nonceSize:] | ||
| 69 | return gcm.Open(nil, nonce, ciphertext, nil) | ||
| 70 | } | ||
| 71 |