AES 加密 Golang 和 Python

Question

我正在为自己做一个有趣的副业。一个 golang 服务器和一个 python 客户端。我希望对传输的数据进行加密，但似乎无法让两种加密方案一起工作。在加密方面我是新手，所以请像在和蹒跚学步的孩子说话一样解释。

这是我的 golang 加密函数：

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
}

这是我的 Python 实现：

 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

我也不能完全弄清楚我的 python 函数的输出。我的 Go 程序运行良好。但我希望能够在 Go 中加密，在 python 中解密，反之亦然。

Python 的示例输出：

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

如您所见，消息已解密，但在字符串末尾结束？

编辑： 从 GO 解密的示例输出。 如果我尝试使用 GO 解密以下内容（使用 Python 生成）

ECRYPTED STRING: (Test Message) 7af474bc4c8ea9579d83a3353f83a0c2844f8efb019c82618ea0b478

我明白了

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

奇怪的是第一个字符总是正确的

这是两个完整的项目：

Github

Answer 1

Python 使用 8 位段，而 Go 使用 128 位段，所以第一个字符有效但后面的无效的原因是因为每个段都依赖于前一个段，因此不同的段大小会破坏链。

我为 Python 制作了这些 URL 安全（未填充的 base64 编码）加密/解密函数，以选择性地加密与 Go 相同的方式（当您指定 block_segments=True 时）。

def decrypt(key, value, block_segments=False):
    # The base64 library fails if value is Unicode. Luckily, base64 is ASCII-safe.
    value = str(value)
    # We add back the padding ("=") here so that the decode won't fail.
    value = base64.b64decode(value + '=' * (4 - len(value) % 4), '-_')
    iv, value = value[:AES.block_size], value[AES.block_size:]
    if block_segments:
        # Python uses 8-bit segments by default for legacy reasons. In order to support
        # languages that encrypt using 128-bit segments, without having to use data with
        # a length divisible by 16, we need to pad and truncate the values.
        remainder = len(value) % 16
        padded_value = value + '\0' * (16 - remainder) if remainder else value
        cipher = AES.new(key, AES.MODE_CFB, iv, segment_size=128)
        # Return the decrypted string with the padding removed.
        return cipher.decrypt(padded_value)[:len(value)]
    return AES.new(key, AES.MODE_CFB, iv).decrypt(value)


def encrypt(key, value, block_segments=False):
    iv = Random.new().read(AES.block_size)
    if block_segments:
        # See comment in decrypt for information.
        remainder = len(value) % 16
        padded_value = value + '\0' * (16 - remainder) if remainder else value
        cipher = AES.new(key, AES.MODE_CFB, iv, segment_size=128)
        value = cipher.encrypt(padded_value)[:len(value)]
    else:
        value = AES.new(key, AES.MODE_CFB, iv).encrypt(value)
    # The returned value has its padding stripped to avoid query string issues.
    return base64.b64encode(iv + value, '-_').rstrip('=')

请注意，为了安全消息传递，您需要额外的安全功能，例如防止重放攻击的随机数。

以下是 Go 的等效函数：

func Decrypt(key []byte, encrypted string) ([]byte, error) {
    ciphertext, err := base64.RawURLEncoding.DecodeString(encrypted)
    if err != nil {
        return nil, err
    }
    block, err := aes.NewCipher(key)
    if err != nil {
        return nil, err
    }
    if len(ciphertext) < aes.BlockSize {
        return nil, errors.New("ciphertext too short")
    }
    iv := ciphertext[:aes.BlockSize]
    ciphertext = ciphertext[aes.BlockSize:]
    cfb := cipher.NewCFBDecrypter(block, iv)
    cfb.XORKeyStream(ciphertext, ciphertext)
    return ciphertext, nil
}

func Encrypt(key, data []byte) (string, error) {
    block, err := aes.NewCipher(key)
    if err != nil {
        return "", err
    }
    ciphertext := make([]byte, aes.BlockSize+len(data))
    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:], data)
    return base64.RawURLEncoding.EncodeToString(ciphertext), nil
}

Answer 2

您在 Python 中解密期间忘记切掉 IV。改变

x=(cipher.decrypt( enc ))

到

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

或到

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