用Bouncycastle jar替换JCE [英] replace JCE with Bouncycastle jar

问题描述

我必须摆脱JCE jar，应该替换为弹性城堡jar AES加密和解密。

I have to get rid of JCE jars and should be replaced with bouncy castle jar for AES encryption and decryption.

我更换无效的键大小异常，当我更换JCE策略jar与BC jar为AES 256算法。但它适用于键大小128.

I am getting invalid key size exception when i replace JCE policy jars with BC jars for AES 256 algorithm. But it works well with key size 128.

如果是AES 256算法，我如何使用BC jar。

How can i make use of BC jars in case of AES 256 algorithm.

感谢。

推荐答案

Cipher 是在 Cipher 类本身。

而是可以使用Bouncy Castle轻量级API。

Instead you could use the Bouncy Castle lightweight API. The lightweight API is lightweight for the amount of classes are required for the API implementation itself, not so much for you though.

例如（AES CBC with PKCS＃7（ PKCS＃5 compatible）padding：

For example (AES CBC with PKCS#7 (PKCS#5 compatible) padding:

public class BouncyLightWeightCipherExample {

    private static final boolean FOR_DECRYPTION = false;

    public static void main(String[] args) throws NoSuchAlgorithmException, Exception {
        final byte[] keyData = new byte[256 / Byte.SIZE];
        final byte[] ivData = new byte[16];
        final byte[] testData = "owlstead".getBytes(UTF_8);

        // JCE creation
        final Cipher c = Cipher.getInstance("AES/CBC/PKCS5Padding");

        // initialization
        c.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(keyData, "AES"), new IvParameterSpec(ivData));

        // and encryption
        final byte[] ciphertext = c.doFinal(testData);

        // Bouncy Castle creation
        final BlockCipher blockCipher = new AESFastEngine();
        final CBCBlockCipher withModeOfOperation = new CBCBlockCipher(blockCipher);
        final PaddedBufferedBlockCipher withPadding = new PaddedBufferedBlockCipher(withModeOfOperation);

        // initialization
        final ParametersWithIV keyAndIV = new ParametersWithIV(new KeyParameter(keyData), ivData);
        withPadding.init(FOR_DECRYPTION, keyAndIV);

        // and decryption
        int plaintextSize = withPadding.processBytes(ciphertext, 0, ciphertext.length, ciphertext, 0);
        plaintextSize += withPadding.doFinal(ciphertext, plaintextSize);
        final byte[] plaintext = Arrays.copyOf(ciphertext, plaintextSize);

        // there we are
        System.out.println(new String(plaintext, UTF_8));
    }
}

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