org.bouncycastle.util.encoders.DecoderException: unable to decode base64 string: String index out of range: -4

这个错误是由于尝试解码一个无效的 base64 字符串而引起的。具体说来，这个错误是因为字符串的索引超出范围导致的。你可以检查一下你提供的 base64 字符串是否正确，并确保没有出现任何错误或截断。另外，你也可以尝试使用其他的 base64 解码方法来处理这个字符串。如果问题仍然存在，可能需要进一步检查代码逻辑或调整输入数据来解决问题。

相关问题

bouncycastle generate IPEK according to BDK and KSN example

As an AI language model, I don't have access to examples of keys or sensitive information. However, I can provide you with the general steps for generating an IPEK using BouncyCastle:

1. Generate a random 16-byte key, called the "Key Encryption Key" (KEK).
2. Using the KEK and the BDK (Base Derivation Key), generate a 16-byte key called the "Initial PIN Encryption Key" (IPEK).
3. XOR the IPEK with the first 8 bytes of the KSN (Key Serial Number) to generate the "PIN Encryption Key" (PEK).
4. XOR the IPEK with the second 8 bytes of the KSN to generate the "Data Encryption Key" (DEK).

Here's the Java code using BouncyCastle:

import org.bouncycastle.crypto.engines.AESEngine;
import org.bouncycastle.crypto.modes.CBCBlockCipher;
import org.bouncycastle.crypto.params.KeyParameter;
import org.bouncycastle.crypto.params.ParametersWithIV;
import org.bouncycastle.util.encoders.Hex;

public class IpekGenerator {
    private static final byte[] BDK = Hex.decode("0123456789ABCDEFFEDCBA9876543210");
    private static final byte[] KSN = Hex.decode("FFFF9876543210E00001");

    public static void main(String[] args) {
        // Generate KEK
        byte[] kek = new byte[16];
        new SecureRandom().nextBytes(kek);

        // Generate IPEK
        byte[] ipek = generateIpek(BDK, kek);
        System.out.println("IPEK: " + Hex.toHexString(ipek));

        // Generate PEK and DEK
        byte[] pek = generatePek(ipek, KSN);
        byte[] dek = generateDek(ipek, KSN);
        System.out.println("PEK: " + Hex.toHexString(pek));
        System.out.println("DEK: " + Hex.toHexString(dek));
    }

    private static byte[] generateIpek(byte[] bdk, byte[] kek) {
        byte[] data = new byte[16];
        System.arraycopy(kek, 0, data, 0, 8);
        System.arraycopy(bdk, 0, data, 8, 8);

        CBCBlockCipher cipher = new CBCBlockCipher(new AESEngine());
        ParametersWithIV params = new ParametersWithIV(new KeyParameter(bdk), new byte[16]);
        cipher.init(true, params);

        byte[] ipek = new byte[16];
        cipher.processBlock(data, 0, ipek, 0);
        return ipek;
    }

    private static byte[] generatePek(byte[] ipek, byte[] ksn) {
        byte[] pek = new byte[8];
        for (int i = 0; i < 8; i++) {
            pek[i] = (byte) (ipek[i] ^ ksn[i]);
        }
        return pek;
    }

    private static byte[] generateDek(byte[] ipek, byte[] ksn) {
        byte[] dek = new byte[8];
        for (int i = 0; i < 8; i++) {
            dek[i] = (byte) (ipek[i + 8] ^ ksn[i]);
        }
        return dek;
    }
}

BouncyCastle使用

Bouncy Castle可以通过下载相应的jar包并将其添加到项目中来使用。在Java中，你可以使用Bouncy Castle提供的API来访问其提供的加密算法和协议。下面是一个简单的示例，演示如何使用Bouncy Castle进行AES加密和解密：

import org.bouncycastle.crypto.BufferedBlockCipher;
import org.bouncycastle.crypto.engines.AESEngine;
import org.bouncycastle.crypto.modes.CBCBlockCipher;
import org.bouncycastle.crypto.paddings.PaddedBufferedBlockCipher;
import org.bouncycastle.crypto.params.KeyParameter;
import org.bouncycastle.crypto.params.ParametersWithIV;
import org.bouncycastle.util.encoders.Base64;

import java.security.SecureRandom;

public class BouncyCastleExample {
    private static final int KEY_SIZE = 256;
    private static final int IV_SIZE = 128;
    private static final int BLOCK_SIZE = 128;
    private static final String KEY = "my_secret_key";
    private static final String PLAIN_TEXT = "Hello, world!";

    public static void main(String[] args) throws Exception {
        SecureRandom random = new SecureRandom();
        byte[] keyBytes = KEY.getBytes();
        byte[] ivBytes = new byte[IV_SIZE / 8];
        random.nextBytes(ivBytes);

        BufferedBlockCipher cipher = new PaddedBufferedBlockCipher(new CBCBlockCipher(new AESEngine()));
        KeyParameter keyParam = new KeyParameter(keyBytes);
        ParametersWithIV params = new ParametersWithIV(keyParam, ivBytes);
        cipher.init(true, params);

        byte[] input = PLAIN_TEXT.getBytes();
        byte[] output = new byte[cipher.getOutputSize(input.length)];
        int len = cipher.processBytes(input, 0, input.length, output, 0);
        len += cipher.doFinal(output, len);

        String base64Encoded = new String(Base64.encode(output));
        System.out.println("Encrypted text: " + base64Encoded);

        cipher = new PaddedBufferedBlockCipher(new CBCBlockCipher(new AESEngine()));
        params = new ParametersWithIV(keyParam, ivBytes);
        cipher.init(false, params);

        byte[] decoded = Base64.decode(base64Encoded);
        byte[] decrypted = new byte[cipher.getOutputSize(decoded.length)];
        len = cipher.processBytes(decoded, 0, decoded.length, decrypted, 0);
        len += cipher.doFinal(decrypted, len);

        System.out.println("Decrypted text: " + new String(decrypted));
    }
}

在上面的示例中，我们使用Bouncy Castle提供的AES算法和CBC模式来加密和解密数据。我们首先生成一个随机的IV（初始化向量），并使用它和我们的密钥一起初始化加密/解密器。在加密时，我们将输入数据转换为字节数组，将其传递给加密器，并将加密后的结果编码为Base64字符串。在解密时，我们对编码后的字符串进行解码，然后使用相同的IV和密钥初始化解密器，并将解密后的结果转换为字符串。