/
crypt.go
60 lines (56 loc) · 1.44 KB
/
crypt.go
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package util
import (
"crypto/aes"
"crypto/cipher"
"crypto/rand"
"encoding/base64"
"errors"
"io"
)
// example
// key := []byte("a very very very very secret key") // 32 bytes
// plaintext := []byte("some really really really long plaintext")
// fmt.Printf("%s\n", plaintext)
// ciphertext, err := encrypt(key, plaintext)
// if err != nil {
// log.Fatal(err)
// }
// fmt.Printf("%0x\n", ciphertext)
// result, err := decrypt(key, ciphertext)
// if err != nil {
// log.Fatal(err)
// }
// fmt.Printf("%s\n", result)
func Encrypt(key, text []byte) ([]byte, error) {
block, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
b := base64.StdEncoding.EncodeToString(text)
ciphertext := make([]byte, aes.BlockSize+len(b))
iv := ciphertext[:aes.BlockSize]
if _, err := io.ReadFull(rand.Reader, iv); err != nil {
return nil, err
}
cfb := cipher.NewCFBEncrypter(block, iv)
cfb.XORKeyStream(ciphertext[aes.BlockSize:], []byte(b))
return ciphertext, nil
}
func Decrypt(key, text []byte) ([]byte, error) {
block, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
if len(text) < aes.BlockSize {
return nil, errors.New("ciphertext too short")
}
iv := text[:aes.BlockSize]
text = text[aes.BlockSize:]
cfb := cipher.NewCFBDecrypter(block, iv)
cfb.XORKeyStream(text, text)
data, err := base64.StdEncoding.DecodeString(string(text))
if err != nil {
return nil, err
}
return data, nil
}