RSA加解密

最新推荐文章于 2017-10-30 09:15:43 发布

转载最新推荐文章于 2017-10-30 09:15:43 发布 · 69 阅读

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原文链接：https://my.oschina.net/u/2353881/blog/749101

文章标签：

#python

本文介绍了一种使用Java语言实现的RSA私钥解密方法。该方法通过将BASE64编码的私钥转换为PKCS8编码，并利用Java内置的Cipher类完成解密过程。文章提供了完整的代码示例及解密步骤。

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调用代码进行rsa私钥解密:

byte[] bytes = RsaUtils.decryptByPrivateKey(new Base64().decode(context), key);
//加密后字符
String decryptContext = new String(bytes, "UTF-8");

类:RsaUtils

/**
     * <P>
     * 私钥解密
     * </p>
     *
     * @param encryptedData 已加密数据
     * @param privateKey    私钥(BASE64编码)
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey)
            throws Exception {
        byte[] keyBytes = decode(privateKey);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, privateK);
        int inputLen = encryptedData.length;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        int offSet = 0;
        byte[] cache;
        int i = 0;
        // 对数据分段解密
        while (inputLen - offSet > 0) {
            if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
                cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
            } else {
                cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
            }
            out.write(cache, 0, cache.length);
            i++;
            offSet = i * MAX_DECRYPT_BLOCK;
        }
        byte[] decryptedData = out.toByteArray();
        out.close();
        return decryptedData;
    }

    /**
     * <p>
     * BASE64字符串解码为二进制数据
     * </p>
     *
     * @param base64
     * @return
     * @throws Exception
     */
    public static byte[] decode(String base64) throws Exception {
//        return Base64.decode(base64.getBytes());
        return new org.apache.commons.codec.binary.Base64().decode(base64.getBytes());
    }

转载于:https://my.oschina.net/u/2353881/blog/749101