Issue
I want to be able to decrypt in Go what was encrypted in Python. The encrypting/decrypting functions work respectively in each language but not when I am encrypting in Python and decrypting in Go, I am guessing there is something wrong with the encoding because I am getting gibberish output:
Rx����d��I�K|�ap���k��B%F���UV�~d3h�����|�����>�B��B�
Encryption/Decryption in Python
def encrypt(plaintext, key=config.SECRET, key_salt='', no_iv=False):
"""Encrypt shit the right way"""
# sanitize inputs
key = SHA256.new((key + key_salt).encode()).digest()
if len(key) not in AES.key_size:
raise Exception()
if isinstance(plaintext, string_types):
plaintext = plaintext.encode('utf-8')
# pad plaintext using PKCS7 padding scheme
padlen = AES.block_size - len(plaintext) % AES.block_size
plaintext += (chr(padlen) * padlen).encode('utf-8')
# generate random initialization vector using CSPRNG
if no_iv:
iv = ('\0' * AES.block_size).encode()
else:
iv = get_random_bytes(AES.block_size)
log.info(AES.block_size)
# encrypt using AES in CFB mode
ciphertext = AES.new(key, AES.MODE_CFB, iv).encrypt(plaintext)
# prepend iv to ciphertext
if not no_iv:
ciphertext = iv + ciphertext
# return ciphertext in hex encoding
log.info(ciphertext)
return ciphertext.hex()
def decrypt(ciphertext, key=config.SECRET, key_salt='', no_iv=False):
"""Decrypt shit the right way"""
# sanitize inputs
key = SHA256.new((key + key_salt).encode()).digest()
if len(key) not in AES.key_size:
raise Exception()
if len(ciphertext) % AES.block_size:
raise Exception()
try:
ciphertext = codecs.decode(ciphertext, 'hex')
except TypeError:
log.warning("Ciphertext wasn't given as a hexadecimal string.")
# split initialization vector and ciphertext
if no_iv:
iv = '\0' * AES.block_size
else:
iv = ciphertext[:AES.block_size]
ciphertext = ciphertext[AES.block_size:]
# decrypt ciphertext using AES in CFB mode
plaintext = AES.new(key, AES.MODE_CFB, iv).decrypt(ciphertext).decode()
# validate padding using PKCS7 padding scheme
padlen = ord(plaintext[-1])
if padlen < 1 or padlen > AES.block_size:
raise Exception()
if plaintext[-padlen:] != chr(padlen) * padlen:
raise Exception()
plaintext = plaintext[:-padlen]
return plaintext
Encryption/Decryption in Go
// PKCS5Padding adds padding to the plaintext to make it a multiple of the block size
func PKCS5Padding(src []byte, blockSize int) []byte {
padding := blockSize - len(src)%blockSize
padtext := bytes.Repeat([]byte{byte(padding)}, padding)
return append(src, padtext...)
}
// Encrypt encrypts the plaintext,the input salt should be a random string that is appended to the plaintext
// that gets fed into the one-way function that hashes it.
func Encrypt(plaintext) string {
h := sha256.New()
h.Write([]byte(os.Getenv("SECRET")))
key := h.Sum(nil)
plaintextBytes := PKCS5Padding([]byte(plaintext), aes.BlockSize)
block, err := aes.NewCipher(key)
if err != nil {
panic(err)
}
// The IV needs to be unique, but not secure. Therefore it's common to
// include it at the beginning of the ciphertext.
ciphertext := make([]byte, aes.BlockSize+len(plaintextBytes))
iv := ciphertext[:aes.BlockSize]
if _, err := io.ReadFull(rand.Reader, iv); err != nil {
panic(err)
}
stream := cipher.NewCFBEncrypter(block, iv)
stream.XORKeyStream(ciphertext[aes.BlockSize:], plaintextBytes)
// return hexadecimal representation of the ciphertext
return hex.EncodeToString(ciphertext)
}
func PKCS5UnPadding(src []byte) []byte {
length := len(src)
unpadding := int(src[length-1])
return src[:(length - unpadding)]
}
func Decrypt(ciphertext string) string {
h := sha256.New()
// have to check if the secret is hex encoded
h.Write([]byte(os.Getenv("SECRET")))
key := h.Sum(nil)
ciphertext_bytes := []byte(ciphertext)
block, err := aes.NewCipher(key)
if err != nil {
panic(err)
}
log.Print(aes.BlockSize)
// The IV needs to be unique, but not secure. Therefore it's common to
// include it at the beginning of the ciphertext.
iv := ciphertext_bytes[:aes.BlockSize]
if len(ciphertext) < aes.BlockSize {
panic("ciphertext too short")
}
ciphertext_bytes = ciphertext_bytes[aes.BlockSize:]
stream := cipher.NewCFBDecrypter(block, iv)
stream.XORKeyStream(ciphertext_bytes, ciphertext_bytes)
plaintext := PKCS5UnPadding(ciphertext_bytes)
return string(plaintext)
}
