java/php/c#版rsa签名以及java验签实现

       在开放平台领域，需要给isv提供sdk，签名是Sdk中需要提供的功能之一。由于isv使用的开发语言不是单一的，因此sdk需要提供多种语言的版本。譬如java、php、c#。另外，在电子商务尤其是支付领域，对安全性的要求比较高，所以会采用非对称密钥RSA

       本文主要介绍如何基于java、php、c#在客户端使用rsa签名，然后在服务端使用Java验签。

1. 基于openssl生成RSA公私钥对

  b）生成私钥

进入到openssl的bin目录下，执行以下命令：

openssl genrsa -out rsa_private_key.pem 1024

会在bin目录下看到新生成的私钥文件rsa_private_key.pem，文件内容如下：

-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----

   c)生成公钥

在bin目录下，执行以下命令：

openssl rsa -in rsa_private_key.pem -pubout -out rsa_public_key.pem

会在bin目录下看到新生成的公钥文件rsa_public_key.pem，文件内容如下：

-----BEGIN PUBLIC KEY-----
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDtd1lKsX6ylsAEWFi7E/ut8krJ
y9PQ7sGYKhIm9TvIdZiq5xzyaw8NOLzKZ1k486MePYG4tSuoaxSbwuPLwVUzYFvn
UZo7aWCIGKn16UWTM4nxc/+dwce+bhcKrlLbTWi8l580LTE7GxclTh8z7gHq59iv
haoGbK7FNxlUfB4TSQIDAQAB
-----END PUBLIC KEY-----

 2. 客户端签名

  2.1 java版签名实现

/**
     * rsa签名
     * 
     * @param content
     *            待签名的字符串
     * @param privateKey
     *            rsa私钥字符串
     * @param charset
     *            字符编码
     * @return 签名结果
     * @throws Exception
     *             签名失败则抛出异常
     */
    public String rsaSign(String content, String privateKey, String charset) throws SignatureException {
        try {
            PrivateKey priKey = getPrivateKeyFromPKCS8("RSA", new ByteArrayInputStream(privateKey.getBytes()));

            Signature signature = Signature.getInstance("SHA1WithRSA");
            signature.initSign(priKey);
            if (StringUtils.isEmpty(charset)) {
                signature.update(content.getBytes());
            } else {
                signature.update(content.getBytes(charset));
            }

            byte[] signed = signature.sign();
            return new String(Base64.encodeBase64(signed));
        } catch (Exception e) {
            throw new SignatureException("RSAcontent = " + content + "; charset = " + charset, e);
        }
    }

    public PrivateKey getPrivateKeyFromPKCS8(String algorithm, InputStream ins) throws Exception {
        if (ins == null || StringUtils.isEmpty(algorithm)) {
            return null;
        }

        KeyFactory keyFactory = KeyFactory.getInstance(algorithm);
        byte[] encodedKey = StreamUtil.readText(ins).getBytes();
        encodedKey = Base64.decodeBase64(encodedKey);
        return keyFactory.generatePrivate(new PKCS8EncodedKeySpec(encodedKey));
    }

 注意：参数privateKey是Pem私钥文件中去除头（-----BEGIN RSA PRIVATE KEY-----）和尾（-----END RSA PRIVATE KEY-----）以及换行符后的字符串。

如果签名报以下错误：

java.security.spec.InvalidKeySpecException: java.security.InvalidKeyException: IOException : algid parse error, not a sequence

则说明rsa私钥的格式不是pksc8格式，需要使用以下命令转换一下：

openssl pkcs8 -topk8 -inform PEM -in rsa_private_key.pem -outform PEM -nocrypt

然后再提取去除头和尾以及换行符后字符串作为java版用的rsa私钥

  2.2 php签名实现

function sign($content, $rsaPrivateKeyPem) {
		$priKey = file_get_contents($rsaPrivateKeyPem);
		$res = openssl_get_privatekey($priKey);
		openssl_sign($content, $sign, $res);
		openssl_free_key($res);
		$sign = base64_encode($sign);
		return $sign;
	}

 注意：$rsaPrivateKeyPem为pem私钥文件路径

  2.3 c#签名实现(引用了国外某位仁兄的方案)

using System;
using System.Text;
using System.Security.Cryptography;
using System.Web;
using System.IO;

namespace Aop.Api.Util
{
    /// <summary>
    /// RSA签名工具类。
    /// </summary>
    public class RSAUtil
    {

        public static string RSASign(string data, string privateKeyPem)
        {
            RSACryptoServiceProvider rsaCsp = LoadCertificateFile(privateKeyPem);
            byte[] dataBytes = Encoding.UTF8.GetBytes(data);
            byte[] signatureBytes = rsaCsp.SignData(dataBytes, "SHA1");
            return Convert.ToBase64String(signatureBytes);
        }

        private static byte[] GetPem(string type, byte[] data)
        {
            string pem = Encoding.UTF8.GetString(data);
            string header = String.Format("-----BEGIN {0}-----\\n", type);
            string footer = String.Format("-----END {0}-----", type);
            int start = pem.IndexOf(header) + header.Length;
            int end = pem.IndexOf(footer, start);
            string base64 = pem.Substring(start, (end - start));
            return Convert.FromBase64String(base64);
        }

        private static RSACryptoServiceProvider LoadCertificateFile(string filename)
        {
            using (System.IO.FileStream fs = System.IO.File.OpenRead(filename))
            {
                byte[] data = new byte[fs.Length];
                byte[] res = null;
                fs.Read(data, 0, data.Length);
                if (data[0] != 0x30)
                {
                    res = GetPem("RSA PRIVATE KEY", data);
                }
                try
                {
                    RSACryptoServiceProvider rsa = DecodeRSAPrivateKey(res);
                    return rsa;
                }
                catch (Exception ex)
                {
                }
                return null;
            }
        }

        private static RSACryptoServiceProvider DecodeRSAPrivateKey(byte[] privkey)
        {
            byte[] MODULUS, E, D, P, Q, DP, DQ, IQ;

            // --------- Set up stream to decode the asn.1 encoded RSA private key ------
            MemoryStream mem = new MemoryStream(privkey);
            BinaryReader binr = new BinaryReader(mem);  //wrap Memory Stream with BinaryReader for easy reading
            byte bt = 0;
            ushort twobytes = 0;
            int elems = 0;
            try
            {
                twobytes = binr.ReadUInt16();
                if (twobytes == 0x8130) //data read as little endian order (actual data order for Sequence is 30 81)
                    binr.ReadByte();    //advance 1 byte
                else if (twobytes == 0x8230)
                    binr.ReadInt16();    //advance 2 bytes
                else
                    return null;

                twobytes = binr.ReadUInt16();
                if (twobytes != 0x0102) //version number
                    return null;
                bt = binr.ReadByte();
                if (bt != 0x00)
                    return null;


                //------ all private key components are Integer sequences ----
                elems = GetIntegerSize(binr);
                MODULUS = binr.ReadBytes(elems);

                elems = GetIntegerSize(binr);
                E = binr.ReadBytes(elems);

                elems = GetIntegerSize(binr);
                D = binr.ReadBytes(elems);

                elems = GetIntegerSize(binr);
                P = binr.ReadBytes(elems);

                elems = GetIntegerSize(binr);
                Q = binr.ReadBytes(elems);

                elems = GetIntegerSize(binr);
                DP = binr.ReadBytes(elems);

                elems = GetIntegerSize(binr);
                DQ = binr.ReadBytes(elems);

                elems = GetIntegerSize(binr);
                IQ = binr.ReadBytes(elems);
                

                // ------- create RSACryptoServiceProvider instance and initialize with public key -----
                CspParameters CspParameters = new CspParameters();
                CspParameters.Flags = CspProviderFlags.UseMachineKeyStore;
                RSACryptoServiceProvider RSA = new RSACryptoServiceProvider(1024, CspParameters);
                RSAParameters RSAparams = new RSAParameters();
                RSAparams.Modulus = MODULUS;
                RSAparams.Exponent = E;
                RSAparams.D = D;
                RSAparams.P = P;
                RSAparams.Q = Q;
                RSAparams.DP = DP;
                RSAparams.DQ = DQ;
                RSAparams.InverseQ = IQ;
                RSA.ImportParameters(RSAparams);
                return RSA;
            }
            catch (Exception ex)
            {
                return null;
            }
            finally
            {
                binr.Close();
            }
        }

        private static int GetIntegerSize(BinaryReader binr)
        {
            byte bt = 0;
            byte lowbyte = 0x00;
            byte highbyte = 0x00;
            int count = 0;
            bt = binr.ReadByte();
            if (bt != 0x02)		//expect integer
                return 0;
            bt = binr.ReadByte();

            if (bt == 0x81)
                count = binr.ReadByte();	// data size in next byte
            else
                if (bt == 0x82)
                {
                    highbyte = binr.ReadByte();	// data size in next 2 bytes
                    lowbyte = binr.ReadByte();
                    byte[] modint = { lowbyte, highbyte, 0x00, 0x00 };
                    count = BitConverter.ToInt32(modint, 0);
                }
                else
                {
                    count = bt;		// we already have the data size
                }

            while (binr.ReadByte() == 0x00)
            {	//remove high order zeros in data
                count -= 1;
            }
            binr.BaseStream.Seek(-1, SeekOrigin.Current);		//last ReadByte wasn't a removed zero, so back up a byte
            return count;
        }
    }
}

 注：privateKeyPem为私钥文件路径

  3. 服务端java验签

/**
     * rsa验签
     * 
     * @param content 被签名的内容
     * @param sign 签名后的结果
     * @param publicKey rsa公钥
     * @param charset 字符集
     * @return 验签结果
     * @throws SignatureException 验签失败，则抛异常
     */
    boolean doCheck(String content, String sign, String publicKey, String charset) throws SignatureException {
        try {
            PublicKey pubKey = getPublicKeyFromX509("RSA", new ByteArrayInputStream(publicKey.getBytes()));

            Signature signature = Signature.getInstance("SHA1WithRSA");
            signature.initVerify(pubKey);
            signature.update(getContentBytes(content, charset));
            return signature.verify(Base64.decodeBase64(sign.getBytes()));
        } catch (Exception e) {
            throw new SignatureException("RSA验证签名[content = " + content + "; charset = " + charset
                                         + "; signature = " + sign + "]发生异常!", e);
        }
    }

    private PublicKey getPublicKeyFromX509(String algorithm, InputStream ins) throws NoSuchAlgorithmException {
        try {
            KeyFactory keyFactory = KeyFactory.getInstance(algorithm);

            StringWriter writer = new StringWriter();
            StreamUtil.io(new InputStreamReader(ins), writer);
            byte[] encodedKey = writer.toString().getBytes();

            // 先base64解码
            encodedKey = Base64.decodeBase64(encodedKey);
            return keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey));
        } catch (IOException ex) {
            // 不可能发生
        } catch (InvalidKeySpecException ex) {
            // 不可能发生
        }
        return null;
    }

    private byte[] getContentBytes(String content, String charset) throws UnsupportedEncodingException {
        if (StringUtil.isEmpty(charset)) {
            return content.getBytes();
        }

        return content.getBytes(charset);
    }

 注意：参数publicKey是Pem公钥文件中去除头（-----BEGIN RSA PRIVATE KEY-----）和尾（-----END RSA PRIVATE KEY-----）以及换行符后的字符串。

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