AES加密Golang和Python

Question

I am working on a fun side project for myself. A golang server and a python client. I want data transmitted to be encrypted but cant seem to get the two encryption schemes working together. I am a novice when it comes to encryption so please explain like you are talking to a toddler.

Here is my golang encryption functions:

import (
    "crypto/aes"
    "crypto/cipher"
    "crypto/rand"
    "errors"
    "io"
    "fmt"
)
func Encrypt(key, text []byte) (ciphertext []byte, err error) {
    var block cipher.Block
    if block, err = aes.NewCipher(key); err != nil {
        return nil, err
    }
    ciphertext = make([]byte, aes.BlockSize+len(string(text)))
    iv := ciphertext[:aes.BlockSize]
    fmt.Println(aes.BlockSize)
    if _, err = io.ReadFull(rand.Reader, iv); err != nil {
        return
    }
    cfb := cipher.NewCFBEncrypter(block, iv)
    cfb.XORKeyStream(ciphertext[aes.BlockSize:], text)
    return
}

func Decrypt(key, ciphertext []byte) (plaintext []byte, err error) {
    var block cipher.Block
    if block, err = aes.NewCipher(key); err != nil {
        return
    }
    if len(ciphertext) < aes.BlockSize {
        err = errors.New("ciphertext too short")
        return
    }
    iv := ciphertext[:aes.BlockSize]
    ciphertext = ciphertext[aes.BlockSize:]
    cfb := cipher.NewCFBDecrypter(block, iv)
    cfb.XORKeyStream(ciphertext, ciphertext)
    plaintext = ciphertext
    return
}

and here is my Python implementation:

 class AESCipher:
    def __init__( self, key ):
        self.key = key
        print "INIT KEY" + hexlify(self.key)
    def encrypt( self, raw ):
        print "RAW STRING: " + hexlify(raw)
        iv = Random.new().read( AES.block_size )
        cipher = AES.new( self.key, AES.MODE_CFB, iv )
        r = ( iv + cipher.encrypt( raw ) )
        print "ECRYPTED STRING: " + hexlify(r)
        return r

    def decrypt( self, enc ):
        enc = (enc)
        iv = enc[:16]
        cipher = AES.new(self.key, AES.MODE_CFB, iv)
        x=(cipher.decrypt( enc ))
        print "DECRYPTED STRING: " + hexlify(x)
        return x

i cant quite figure out the output of my python functions either. My Go routines are working perfectly. But i want to be able to encrypt in Go an decrypt in python and vice versa.

Sample Output from Python:

INIT KEY61736466617364666173646661736466
RAW STRING: 54657374206d657373616765
ECRYPTED STRING: dfee33dd40c32fbaf9aac73ac4e0a5a9fc7bd2947d29005dd8d8e21a
dfee33dd40c32fbaf9aac73ac4e0a5a9fc7bd2947d29005dd8d8e21a
DECRYPTED STRING: 77d899b990d2d3172a3229b1b69c6f2554657374206d657373616765
77d899b990d2d3172a3229b1b69c6f2554657374206d657373616765
wØ™¹�ÒÓ*2)±¶œo%Test message

As you can see the message is decrypted but ends up at the end of the string?

EDIT: Sample output decrypting from GO. If i try and decrypt with GO the below (generated with Python)

ECRYPTED STRING: (Test Message) 7af474bc4c8ea9579d83a3353f83a0c2844f8efb019c82618ea0b478

I get

Decrypted Payload: 54 4E 57 9B 90 F8 D6 CD 12 59 0B B1
Decrypted Payload: TNW�����Y�

The strange part is the first character is always correct

here are both full projects:

Github

Answer 1

You forgot to slice off the IV during decryption in Python. Change

x=(cipher.decrypt( enc ))

to

x = cipher.decrypt( enc[16:] )

or to

x = cipher.decrypt( enc )[16:]