RSA 加解密轉換

由於項目的原因，原來的項目使用.net 進行開發，現在需要轉成java， 所以原來的加解密就成了一個棘手的問題。由於數據使用RSA簽名加密，又因為.net 和 Java 加解密算法上的差異，並不能使用同一個私鑰來對原始數據進行解密。所以考慮的方向就是簽名密鑰之間互相轉換。

有幸的是，網絡上也有很多遇到此問題的朋友，網上也有類似的很多解決方法。但是尋找最終的解決方案還是花了很長時間。再加上自己對程序上的修改，得出了比較適合自己轉換的一個解決方案吧。

轉換需要使用BouncyCastle.Crypto.dll

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Xml;
using System.Security.Cryptography;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Asn1.Pkcs;
using Org.BouncyCastle.Pkcs;
using Org.BouncyCastle.Math;
using Org.BouncyCastle.Asn1.X509;
using Org.BouncyCastle.X509;
using Org.BouncyCastle.Security;

namespace RSADemo
{
    public class RSAKeyConvert
    {
        /// <summary>    
        /// RSA私鑰格式轉換，java->.net    
        /// </summary>    
        /// <param name="privateKey">java生成的RSA私鑰</param>    
        /// <returns></returns>   
        public static string RSAPrivateKeyJava2DotNet(string privateKey)
        {

            RsaPrivateCrtKeyParameters privateKeyParam = (RsaPrivateCrtKeyParameters)PrivateKeyFactory.CreateKey(Convert.FromBase64String(privateKey));
            return string.Format("<RSAKeyValue><Modulus>{0}</Modulus><Exponent>{1}</Exponent><P>{2}</P><Q>{3}</Q><DP>{4}</DP><DQ>{5}</DQ><InverseQ>{6}</InverseQ><D>{7}</D></RSAKeyValue>",
            Convert.ToBase64String(privateKeyParam.Modulus.ToByteArrayUnsigned()),
            Convert.ToBase64String(privateKeyParam.PublicExponent.ToByteArrayUnsigned()),
            Convert.ToBase64String(privateKeyParam.P.ToByteArrayUnsigned()),
            Convert.ToBase64String(privateKeyParam.Q.ToByteArrayUnsigned()),
            Convert.ToBase64String(privateKeyParam.DP.ToByteArrayUnsigned()),
            Convert.ToBase64String(privateKeyParam.DQ.ToByteArrayUnsigned()),
            Convert.ToBase64String(privateKeyParam.QInv.ToByteArrayUnsigned()),
             Convert.ToBase64String(privateKeyParam.Exponent.ToByteArrayUnsigned()));
        }
        /// <summary>    
        /// RSA私鑰格式轉換，.net->java    
        /// </summary>    
        /// <param name="privateKey">.net生成的私鑰</param>    
        /// <returns></returns>   
        public static string RSAPrivateKeyDotNet2Java(string privateKey)
        {
            XmlDocument doc = new XmlDocument();
            doc.LoadXml(privateKey);
            BigInteger m = new BigInteger(1, Convert.FromBase64String(doc.DocumentElement.GetElementsByTagName("Modulus")[0].InnerText));
            BigInteger exp = new BigInteger(1, Convert.FromBase64String(doc.DocumentElement.GetElementsByTagName("Exponent")[0].InnerText));
            BigInteger d = new BigInteger(1, Convert.FromBase64String(doc.DocumentElement.GetElementsByTagName("D")[0].InnerText));
            BigInteger p = new BigInteger(1, Convert.FromBase64String(doc.DocumentElement.GetElementsByTagName("P")[0].InnerText));
            BigInteger q = new BigInteger(1, Convert.FromBase64String(doc.DocumentElement.GetElementsByTagName("Q")[0].InnerText));
            BigInteger dp = new BigInteger(1, Convert.FromBase64String(doc.DocumentElement.GetElementsByTagName("DP")[0].InnerText));
            BigInteger dq = new BigInteger(1, Convert.FromBase64String(doc.DocumentElement.GetElementsByTagName("DQ")[0].InnerText));
            BigInteger qinv = new BigInteger(1, Convert.FromBase64String(doc.DocumentElement.GetElementsByTagName("InverseQ")[0].InnerText));
            RsaPrivateCrtKeyParameters privateKeyParam = new RsaPrivateCrtKeyParameters(m, exp, d, p, q, dp, dq, qinv);
            PrivateKeyInfo privateKeyInfo = PrivateKeyInfoFactory.CreatePrivateKeyInfo(privateKeyParam);
            byte[] serializedPrivateBytes = privateKeyInfo.ToAsn1Object().GetEncoded();
            return Convert.ToBase64String(serializedPrivateBytes);
        }
        /// <summary>    
        /// RSA公鑰格式轉換，java->.net    
        /// </summary>    
        /// <param name="publicKey">java生成的公鑰</param>    
        /// <returns></returns>    
        public static string RSAPublicKeyJava2DotNet(string publicKey)
        {
            RsaKeyParameters publicKeyParam = (RsaKeyParameters)PublicKeyFactory.CreateKey(Convert.FromBase64String(publicKey));
            return string.Format("<RSAKeyValue><Modulus>{0}</Modulus><Exponent>{1}</Exponent></RSAKeyValue>",
                Convert.ToBase64String(publicKeyParam.Modulus.ToByteArrayUnsigned()),
                Convert.ToBase64String(publicKeyParam.Exponent.ToByteArrayUnsigned()));
        }
        /// <summary>    
        /// RSA公鑰格式轉換，.net->java    
        /// </summary>    
        /// <param name="publicKey">.net生成的公鑰</param>    
        /// <returns></returns>   
        public static string RSAPublicKeyDotNet2Java(string publicKey)
        {
            XmlDocument doc = new XmlDocument(); doc.LoadXml(publicKey);
            BigInteger m = new BigInteger(1, Convert.FromBase64String(doc.DocumentElement.GetElementsByTagName("Modulus")[0].InnerText));
            BigInteger p = new BigInteger(1, Convert.FromBase64String(doc.DocumentElement.GetElementsByTagName("Exponent")[0].InnerText));
            RsaKeyParameters pub = new RsaKeyParameters(false, m, p);
            SubjectPublicKeyInfo publicKeyInfo = SubjectPublicKeyInfoFactory.CreateSubjectPublicKeyInfo(pub);
            byte[] serializedPublicBytes = publicKeyInfo.ToAsn1Object().GetDerEncoded();
            return Convert.ToBase64String(serializedPublicBytes);
        }
    }
}

寫於2016-07-19