/
encrypt.go
53 lines (44 loc) · 1.13 KB
/
encrypt.go
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package crypto
import (
"crypto/aes"
"crypto/cipher"
"crypto/rand"
"errors"
"io"
)
// Encrypt uses AES encryption to symmetrically encrypt plaintext
// Inspired by https://astaxie.gitbooks.io/build-web-application-with-golang/content/en/09.6.html
// Key must be 32 bytes.
func Encrypt(plaintext []byte, key []byte) ([]byte, error) {
c, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
gcm, err := cipher.NewGCM(c)
if err != nil {
return nil, err
}
nonce := make([]byte, gcm.NonceSize())
if _, err = io.ReadFull(rand.Reader, nonce); err != nil {
return nil, err
}
return gcm.Seal(nonce, nonce, plaintext, nil), nil
}
// Decrypt ciphertext using the provided key.
// Key must be 32 bytes.
func Decrypt(ciphertext []byte, key []byte) ([]byte, error) {
c, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
gcm, err := cipher.NewGCM(c)
if err != nil {
return nil, err
}
nonceSize := gcm.NonceSize()
if len(ciphertext) < nonceSize {
return nil, errors.New("ciphertext too short")
}
nonce, ciphertext := ciphertext[:nonceSize], ciphertext[nonceSize:]
return gcm.Open(nil, nonce, ciphertext, nil)
}