Java 等效于 OpenSSL AES CBC 加密

2022-01-10 00:00:00 encryption cryptography openssl java

我不是密码学专业人士，特别是由于 OpenSSL 缺少很多文档，我不确定如何解决这个问题.

I'm not a cryptography profi and specially due to the fact that OpenSSL has lots of missing documentation, I'm not sure how can I solve this problem.

我有一个期望接收加密消息的外部系统.提供的唯一示例以这种方式使用 OpenSSL:

I have an external system which expects to receive encrypted messages. The only example provided uses OpenSSL in this way:

$ openssl enc -aes-256-cbc -a -in t.txt -k testpass
U2FsdGVkX1/RUdaSJKRXhHv3zUyTsQwu5/ar2ECKDlrNyH5GL4xRR4fgxkiWqkS1
cQstcoSIgWfRPSOFj/5OtdNLeNXiVR6MxSKJ+NvS9LyUD8+Rg6XIcYUvxR4gHi3w
DWT44LAMCpRAh1Q0t4Z2g7rwb0D05T6ygLaWvB5zD/xGZD3brTqSlWmiJb9Imgda
M6soZO7BhbYdqWqEUl5r6+EbkD21f6L3NX3hJFo+BJ+VFctiAlBO8NwT5l4ogo/s
GErm8gqRr57XoX/kvKAimg==

t.txt 文件在其中一行包含此字符串:

Where the t.txt file contains this string on one line:

AMOUNT=10&TID=#19:23&CURRENCY=EUR&LANGUAGE=DE&SUCCESS_URL=http://some.url/sucess&ERROR_URL=http://some.url/error&CONFIRMATION_URL=http://some.url/confirm&NAME=customer full name`

我发现 this 其他问题，我已经能够使用以下代码进行加密:

I have found this other question and I have been able to do the encryption using following code:

String password = "passPhrase";
String salt = "15charRandomSalt";
int iterations = 100;

/* Derive the key, given password and salt. */
SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");
KeySpec spec = new PBEKeySpec(password.toCharArray(), salt.getBytes(Charset.forName("UTF8")), iterations, 256);
SecretKey tmp = factory.generateSecret(spec);
SecretKey secret = new SecretKeySpec(tmp.getEncoded(), "AES");

/* Encrypt the message. */
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, secret);
AlgorithmParameters params = cipher.getParameters();
byte[] iv = params.getParameterSpec(IvParameterSpec.class).getIV();
byte[] cipherText = cipher.doFinal(toBeEncrypted.getBytes("UTF-8"));
encryptedData = Base64.getEncoder().encodeToString(cipherText);
encryptedData += Base64.getEncoder().encodeToString(iv);

我无法理解的是我应该如何生成与 OpenSSL 类似的输出(加密数据).我有盐、iv 和 cipherText，OpenSSL 输出 Base64 编码结果是这些连接的结果吗?还是只有其中一个?

What I can not understand is how should I generate similar output (encryptedData) to what OpenSSL does. I have the salt, iv and cipherText, is the OpenSSL output Base64 encoded result of a concatenation of these? or only one single of them?

在加密之前我与其他系统共享的唯一内容是密码短语.如果他们不知道盐和迭代次数，他们如何解密结果?

The only thing I share with that other system before encryption is the pass phrase. How could they decrypt the result if salt and number of iterations is not known to them?

谁能回答那些未知参数，并告诉我上面的代码是否相当于OpenSSL过程?

Can somebody give answers to those unknown parameters and also tell me if the above code is the equivalent of OpenSSL process?

推荐答案

下面是一个Java程序解密上述OPENSSL加密(需要Java 8):

Following is a Java program to decrypt the above OPENSSL encryption (it requires Java 8):

import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.security.MessageDigest;
import java.util.Arrays;
import java.util.Base64;
import java.util.Base64.Decoder;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

public class TestAesDecrypt {

    public static void main(final String[] args) throws Exception {
        final byte[] pass = "testpass".getBytes(StandardCharsets.US_ASCII);
        final byte[] magic = "Salted__".getBytes(StandardCharsets.US_ASCII);
        final String inFile = "e:/t/e.txt";

        String source = new String(Files.readAllBytes(Paths.get(inFile)),
                StandardCharsets.US_ASCII);
        source = source.replaceAll("\s", "");
        final Decoder decoder = Base64.getDecoder();
        final byte[] inBytes = decoder.decode(source);

        final byte[] shouldBeMagic = Arrays.copyOfRange(inBytes, 0,
                magic.length);
        if (!Arrays.equals(shouldBeMagic, magic)) {
            System.out.println("Bad magic number");
            return;
        }

        final byte[] salt = Arrays.copyOfRange(inBytes, magic.length,
                magic.length + 8);

        final byte[] passAndSalt = concat(pass, salt);

        byte[] hash = new byte[0];
        byte[] keyAndIv = new byte[0];
        for (int i = 0; i < 3; i++) {
            final byte[] data = concat(hash, passAndSalt);
            final MessageDigest md = MessageDigest.getInstance("MD5");
            hash = md.digest(data);
            keyAndIv = concat(keyAndIv, hash);
        }

        final byte[] keyValue = Arrays.copyOfRange(keyAndIv, 0, 32);
        final byte[] iv = Arrays.copyOfRange(keyAndIv, 32, 48);
        final Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        final SecretKeySpec key = new SecretKeySpec(keyValue, "AES");
        cipher.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec(iv));
        final byte[] clear = cipher.doFinal(inBytes, 16, inBytes.length - 16);
        final String clearText = new String(clear, StandardCharsets.ISO_8859_1);
        System.out.println(clearText);
    }

    private static byte[] concat(final byte[] a, final byte[] b) {
        final byte[] c = new byte[a.length + b.length];
        System.arraycopy(a, 0, c, 0, a.length);
        System.arraycopy(b, 0, c, a.length, b.length);
        return c;
    }
}

相关文章