BouncyCastle Rijndael 256实现

Question

我修改了这个网站的实现，以包含一个salt：

package de.xxx.yyy.main;

import static org.junit.Assert.*;

import org.bouncycastle.crypto.BlockCipher;
import org.bouncycastle.crypto.BufferedBlockCipher;
import org.bouncycastle.crypto.DataLengthException;
import org.bouncycastle.crypto.InvalidCipherTextException;
import org.bouncycastle.crypto.PBEParametersGenerator;
import org.bouncycastle.crypto.digests.SHA3Digest;
import org.bouncycastle.crypto.engines.RijndaelEngine;
import org.bouncycastle.crypto.generators.PKCS12ParametersGenerator;
import org.bouncycastle.crypto.modes.CBCBlockCipher;
import org.bouncycastle.crypto.paddings.PKCS7Padding;
import org.bouncycastle.crypto.paddings.PaddedBufferedBlockCipher;
import org.bouncycastle.crypto.params.ParametersWithIV;
import org.bouncycastle.util.encoders.Base64;
import org.junit.Test;

public class test {

    private char[] password = "0123456789abcdef0123456789abcdef".toCharArray();
    private byte[] salt = "0123456789".getBytes();
    private int iterationCount = 5;

    @Test
    public void testEncryptRijndael() throws DataLengthException, IllegalStateException, InvalidCipherTextException {

        PKCS12ParametersGenerator pGen = new PKCS12ParametersGenerator(new SHA3Digest(256));
        char[] passwordChars = password;

        final byte[] pkcs12PasswordBytes = PBEParametersGenerator.PKCS12PasswordToBytes(passwordChars);
        pGen.init(pkcs12PasswordBytes, salt , iterationCount );     

        BlockCipher engine = new RijndaelEngine(256);
        CBCBlockCipher cbc = new CBCBlockCipher(engine);
        BufferedBlockCipher cipher = new PaddedBufferedBlockCipher(cbc, new PKCS7Padding());

        ParametersWithIV aesCBCParams = (ParametersWithIV) pGen.generateDerivedParameters(256, 256);
        cipher.init(true, aesCBCParams);

        byte[] input = "Hallo ich bin ein Test".getBytes();
        byte[] cipherText = new byte[cipher.getOutputSize(input.length)];

        int cipherLength = cipher.processBytes(input, 0, input.length, cipherText, 0);
        cipher.doFinal(cipherText, cipherLength);

        String result = new String(Base64.encode(cipherText));
        System.out.println("testEncryptRijndael result : " + result);
        assertEquals("cMoMSNMNsikAkLjaheE6iD48Xkfvo7Y6gS8/zroGfHc=",result);
    }

    @Test
    public void testDecryptRijndael() throws DataLengthException, IllegalStateException, InvalidCipherTextException {
        PKCS12ParametersGenerator pGen = new PKCS12ParametersGenerator(new SHA3Digest(256));
        char[] passwordChars = password;

        final byte[] pkcs12PasswordBytes = PBEParametersGenerator.PKCS12PasswordToBytes(passwordChars);
        pGen.init(pkcs12PasswordBytes, salt , iterationCount );     

        BlockCipher engine = new RijndaelEngine(256);
        CBCBlockCipher cbc = new CBCBlockCipher(engine);
        BufferedBlockCipher cipher = new PaddedBufferedBlockCipher(cbc, new PKCS7Padding());

        ParametersWithIV aesCBCParams = (ParametersWithIV) pGen.generateDerivedParameters(256, 256);
        cipher.init(false, aesCBCParams);

        byte[] output = Base64.decode("cMoMSNMNsikAkLjaheE6iD48Xkfvo7Y6gS8/zroGfHc=".getBytes());
        byte[] cipherText = new byte[cipher.getOutputSize(output.length)];

        int cipherLength = cipher.processBytes(output, 0, output.length, cipherText, 0);
        int outputLength = cipher.doFinal(cipherText, cipherLength);
        outputLength += cipherLength;

        byte[] resultBytes = cipherText;
        if (outputLength != output.length) {
            resultBytes = new byte[outputLength];
            System.arraycopy(
                    cipherText, 0,
                    resultBytes, 0,
                    outputLength
                    );
        }

        String result = new String(resultBytes);
        System.out.println("testDecryptRijndael result : " + result);
        assertEquals("Hallo ich bin ein Test", result);
    }
}

这是一个很好的实现，还是存在一些错误、逻辑错误或安全风险？

Answer 1

您使用了更有趣的测试字符串，而不是"value"，这很好，而且在testEncryptRijndael中，您用更严格的assertEquals代替了assertNotNull。

由于您的测试与原始测试不同，因此最好将它们分别重命名为testEncryptRijndaelWithSalt和testDecryptRijndaelWithSalt。把原件也保留下来。

在原始测试和您的测试中，我都看不到日志记录和打印语句的意义。我想你可以放下这个。它们没有坏处，但它们可能会导致阅读测试输出的坏习惯，而不是专注于添加正确的断言。

在加密和解密的情况下有很多重复。也许您可以将该逻辑移到公共的私有助手方法中。这可以减少可能的键入错误。

我不认为这个if块有什么意义：

if (outputLength != output.length) { // .}

问题是，在单元测试中，一切都应该是可预测的:此时您应该已经知道该条件的结果。如果outputLength应该等于output.length，那么删除if，但保留代码块。否则就把整件事删掉。您可以为条件添加一个断言，作为正常检查。