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/
crypto.go
74 lines (61 loc) · 1.55 KB
/
crypto.go
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package app
import (
"crypto/aes"
"crypto/cipher"
"crypto/rand"
"encoding/base64"
"errors"
"io"
)
func keyPadding(key []byte) []byte {
switch length := len(key); {
case length < 16:
return append(key, make([]byte, 16-length)...)
case length == 16:
return key
case length < 24:
return append(key, make([]byte, 24-length)...)
case length == 24:
return key
case length < 32:
return append(key, make([]byte, 32-length)...)
case length == 32:
return key
case length > 32:
return key[:32]
}
return []byte{}
}
func EncryptAES(key []byte, plainText string) (string, error) {
src := []byte(plainText)
block, err := aes.NewCipher(keyPadding(key))
if err != nil {
return "", err
}
cipherText := make([]byte, aes.BlockSize+len(src))
iv := cipherText[:aes.BlockSize]
if _, err = io.ReadFull(rand.Reader, iv); err != nil {
return "", err
}
stream := cipher.NewCFBEncrypter(block, iv)
stream.XORKeyStream(cipherText[aes.BlockSize:], src)
return base64.URLEncoding.EncodeToString(cipherText), nil
}
func DecryptAES(key []byte, securemess string) (string, error) {
cipherText, err := base64.URLEncoding.DecodeString(securemess)
if err != nil {
return "", err
}
block, err := aes.NewCipher(keyPadding(key))
if err != nil {
return "", err
}
if len(cipherText) < aes.BlockSize {
return "", errors.New("ciphertext block size is too short")
}
iv := cipherText[:aes.BlockSize]
cipherText = cipherText[aes.BlockSize:]
stream := cipher.NewCFBDecrypter(block, iv)
stream.XORKeyStream(cipherText, cipherText)
return string(cipherText), nil
}