[英]Java - Python AES encryption decryption
我有一个使用 AES 的来自 Java(v8) 的加密文本,我试图在 python 中使用相同的 SecretKey、Salt 对其进行解密,但是我在取消索引超出范围的填充时遇到问题。 当我做相反的事情时,即在 python 中加密并在 java 中解密,然后我能够获得文本,但带有一些不需要的前缀。
以下是我尝试过的 java 和 python 代码。
Java 代码(来自 org.apache.commons.codec.binary.Base64 的 Base64)
public static String encrypt(String secretKey, String salt, String value) throws Exception {
Cipher cipher = initCipher(secretKey, salt, Cipher.ENCRYPT_MODE);
byte[] encrypted = cipher.doFinal(value.getBytes());
return Base64.encodeBase64String(encrypted);
}
public static String decrypt(String secretKey, String salt, String encrypted) throws Exception {
Cipher cipher = initCipher(secretKey, salt, Cipher.DECRYPT_MODE);
byte[] original = cipher.doFinal(Base64.decodeBase64(encrypted));
return new String(original);
}
private static Cipher initCipher(String secretKey, String salt, int mode) throws Exception {
SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");
KeySpec spec = new PBEKeySpec(secretKey.toCharArray(), salt.getBytes(), 65536, 256);
SecretKey tmp = factory.generateSecret(spec);
SecretKeySpec skeySpec = new SecretKeySpec(tmp.getEncoded(), "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
cipher.init(mode, skeySpec, new IvParameterSpec(new byte[16]));
return cipher;
}
public static void main(String[] args) throws Exception {
String secretKey = "Secret";
String fSalt = "tJHnN5b1i6wvXMwzYMRk";
String plainText = "England";
String cipherText = encrypt(secretKey, fSalt, plainText);
System.out.println("Cipher: " + cipherText);
// cipherText = "6peDTxE1xgLE4hTGg0PKTnuuhFC1Vftsd7NH9DF/7WM="; // Cipher from python
String dcrCipherText = decrypt(secretKey, fSalt, cipherText);
System.out.println(dcrCipherText);
}
Python 代码(3.6 版)和 Pycrypto V2.6
import base64
import hashlib
import os
from Crypto.Cipher import AES
BS = 16
pad = lambda s: s + (BS - len(s) % BS) * chr(BS - len(s) % BS)
# unpad = lambda s: s[:-ord(s[len(s) - 1:])]
unpad = lambda s: s[0:-s[-1]]
def get_private_key(secretKey, salt):
key = hashlib.pbkdf2_hmac('SHA256', secretKey.encode(), salt.encode(), 65536, 32)
return key
def encrypt(message, salt, secretKey):
private_key = get_private_key(secretKey, salt)
message = pad(message)
iv = os.urandom(BS) # 128-bit IV
cipher = AES.new(private_key, AES.MODE_CBC, iv, segment_size=256)
return base64.b64encode(iv + cipher.encrypt(message))
def decrypt(enc, salt, secretKey):
private_key = get_private_key(secretKey, salt)
enc = base64.b64decode(enc)
iv = enc[:BS]
cipher = AES.new(private_key, AES.MODE_CBC, iv, segment_size=256)
return unpad(cipher.decrypt(enc[BS:]))
secretKey = "Secret"
salt = "tJHnN5b1i6wvXMwzYMRk"
plainText = "England"
cipher = encrypt(plainText, salt, secretKey)
print("Cipher: " + bytes.decode(cipher))
# cipher = "0JrZdg9YBRshfTdr1d4zwQ==" # Cipher from java
decrypted = decrypt(cipher, salt, secretKey)
print("Decrypted " + bytes.decode(decrypted))
Java 解密输出: U or England
当我通过 python 密码时,预期: England
Python 解密输出: unpad = lambda s : s[0:-s[-1]] IndexError: index out of range
,预期: England
我在堆栈上也阅读了有关此问题的其他帖子,但是由于他们使用了不同的模式,因此没有解决。
在 python 中,您将 iv(初始化向量)存储在加密消息的前 16 个字节中。
在 Java 中,您没有做这样的事情——您传递的是一个空的 IV,并将包括前 16 个字节在内的整个消息视为密文。
您需要确保 Java 和 Python 匹配。
要么在两者中都不使用 IV,在这种情况下,您将在 Python 中删除该部分。
或者您在两者中都使用 IV,在这种情况下,您需要更新 Java 代码以生成加密时的随机 IV,并将其添加到加密结果中。 在解密时,Java 代码需要将前 16 个字节作为 IV 并将其传递给Cipher
。
使用pycryptodome
匹配 Java 代码的正确python 3
代码如下:
import base64
from Crypto.Cipher import AES
from Crypto.Util.Padding import unpad,pad
import hashlib
def get_private_key(secretKey, salt):
# _prf = lambda p,s: HMAC.new(p, s, SHA256).digest()
# private_key = PBKDF2(secretKey, salt.encode(), dkLen=32,count=65536, prf=_prf )
# above code is equivalent but slow
key = hashlib.pbkdf2_hmac('SHA256', secretKey.encode(), salt.encode(), 65536, 32)
# KeySpec spec = new PBEKeySpec(secretKey.toCharArray(), salt.getBytes(), 65536, 256);
return key
def encrypt(message, salt, secretKey):
private_key = get_private_key(secretKey, salt)
message = pad(message.encode(), AES.block_size)
iv = "\x00"*AES.block_size # 128-bit IV
cipher = AES.new(private_key, AES.MODE_CBC, iv.encode())
return base64.b64encode(cipher.encrypt(message))
def decrypt(enc, salt, secretKey):
# _prf = lambda p,s: HMAC.new(p, s, SHA256).digest()
# private_key = PBKDF2(secretKey, salt.encode(), dkLen=32,count=65536, prf=_prf )
private_key = get_private_key(secretKey, salt)
enc = base64.b64decode(enc)
iv = "\x00"*AES.block_size
cipher = AES.new(private_key, AES.MODE_CBC, iv.encode())
return unpad(cipher.decrypt(enc), AES.block_size).decode('utf-8')
secretKey = "Secret"
salt = "tJHnN5b1i6wvXMwzYMRk"
plainText = "England"
enc_datta = encrypt(plainText, salt, secretKey)
print(f"Encrypted: {enc_datta}")
# Encrypted: 0JrZdg9YBRshfTdr1d4zwQ==
cipher = "0JrZdg9YBRshfTdr1d4zwQ==" # Cipher from java
decrypted = decrypt(cipher, salt, secretKey)
print(f"Decrypted: {decrypted}" )
# Decrypted: England
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