.net 实现签名验签

本人被要求实现.net的签名验签，还是个.net菜鸡，来分享下采坑过程

依然，签名验签使用的证书格式依然是pem，有关使用openssl将.p12和der转pem的命令请转到php实现签名验签

.net不像php只要将pem文件读出来就可以签名验签，需要解析pem文件的主体内容，获取参数装载特定类，具体看一下代码：

  
//有些函数我也不知道是干嘛的，反正.net的实现要这样，采百家之长，签的了名，验的了签就对了
//自己去单元测试下
//pem文件是我使用的是绝对路径
public class Signature
    {
        //签名,返回256位字节数组
        public static byte[] Sign(string content,string path,string code)
        {
            RSACryptoServiceProvider rsaCsp = RSAProviderPrivate(path);
            byte[] dataBytes = Encoding.UTF8.GetBytes(content);
            byte[] signatureBytes = rsaCsp.SignData(dataBytes, code);
            return signatureBytes;
        }

        //验签
        public static Boolean Verify(string content, byte[] signContent, string path, string code)
        {
            byte[] dataBytes = Encoding.UTF8.GetBytes(content);
            byte[] publicPemBytes = LoadCertificateFile(path, "PUBLIC KEY");

            RSACryptoServiceProvider rsaPub = CreateRsaProviderFromPublicKey(publicPemBytes);
            Boolean flag= rsaPub.VerifyData(dataBytes,code, signContent);
            return flag;
        }

        //加载公私钥证书文件
        private static byte[] LoadCertificateFile(String filePath,string type)
        {
            using (System.IO.FileStream fs = System.IO.File.OpenRead(filePath))
            {
                byte[] data = new byte[fs.Length];
                byte[] res = null;
                fs.Read(data, 0, data.Length);
                if (data[0] != 0x30)
                {
                    res = GetPem(type, data);
                }
                return res;
            }
        }

        private static RSACryptoServiceProvider RSAProviderPrivate(String filePath)
        {
            byte[] res = LoadCertificateFile(filePath, "RSA PRIVATE KEY");

            try
            {
                RSACryptoServiceProvider rsa = DecodeRSAPrivateKey(res);
                return rsa;
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
            }
            return null;

        }

        //获取pem文件的主体内容，并转换成字节数组
        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 bool CompareBytearrays(byte[] a, byte[] b)
        {
            if (a.Length != b.Length)
                return false;
            int i = 0;
            foreach (byte c in a)
            {
                if (c != b[i])
                    return false;
                i++;
            }
            return true;
        }

        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 e)
            {
                Console.WriteLine(e);
                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;
        }

        private static RSAParameters ConvertFromPublicKey(byte[] publicPemBytes)
        {

            byte[] keyData = publicPemBytes;
            if (keyData.Length < 162)
            {
                throw new ArgumentException("pem file content is incorrect.");
            }
            byte[] pemModulus = new byte[128];
            byte[] pemPublicExponent = new byte[3];
            Array.Copy(keyData, 29, pemModulus, 0, 128);
            Array.Copy(keyData, 159, pemPublicExponent, 0, 3);
            RSAParameters para = new RSAParameters();
            para.Modulus = pemModulus;
            para.Exponent = pemPublicExponent;
            return para;
        }

        public static RSACryptoServiceProvider CreateRsaProviderFromPublicKey(byte[] publicKeyBytes)
        {
            byte[] SeqOID = { 0x30, 0x0D, 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01, 0x05, 0x00 };
            byte[] x509key;
            byte[] seq = new byte[15];
            int x509size;

            x509key = publicKeyBytes;
            x509size = x509key.Length;

            using (MemoryStream mem = new MemoryStream(x509key))
            {
                using (BinaryReader binr = new BinaryReader(mem))
                {
                    byte bt = 0;
                    ushort twobytes = 0;

                    twobytes = binr.ReadUInt16();
                    if (twobytes == 0x8130)
                        binr.ReadByte();
                    else if (twobytes == 0x8230)
                        binr.ReadInt16();
                    else
                        return null;

                    seq = binr.ReadBytes(15);
                    if (!CompareBytearrays(seq, SeqOID))
                        return null;

                    twobytes = binr.ReadUInt16();
                    if (twobytes == 0x8103)
                        binr.ReadByte();
                    else if (twobytes == 0x8203)
                        binr.ReadInt16();
                    else
                        return null;

                    bt = binr.ReadByte();
                    if (bt != 0x00)
                        return null;

                    twobytes = binr.ReadUInt16();
                    if (twobytes == 0x8130)
                        binr.ReadByte();
                    else if (twobytes == 0x8230)
                        binr.ReadInt16();
                    else
                        return null;

                    twobytes = binr.ReadUInt16();
                    byte lowbyte = 0x00;
                    byte highbyte = 0x00;

                    if (twobytes == 0x8102)
                        lowbyte = binr.ReadByte();
                    else if (twobytes == 0x8202)
                    {
                        highbyte = binr.ReadByte();
                        lowbyte = binr.ReadByte();
                    }
                    else
                        return null;
                    byte[] modint = { lowbyte, highbyte, 0x00, 0x00 };
                    int modsize = BitConverter.ToInt32(modint, 0);

                    int firstbyte = binr.PeekChar();
                    if (firstbyte == 0x00)
                    {
                        binr.ReadByte();
                        modsize -= 1;
                    }

                    byte[] modulus = binr.ReadBytes(modsize);

                    if (binr.ReadByte() != 0x02)
                        return null;
                    int expbytes = (int)binr.ReadByte();
                    byte[] exponent = binr.ReadBytes(expbytes);

                    RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();
                    RSAParameters RSAKeyInfo = new RSAParameters();
                    RSAKeyInfo.Modulus = modulus;
                    RSAKeyInfo.Exponent = exponent;
                    RSA.ImportParameters(RSAKeyInfo);

                    return RSA;
                }

            }
        }

    }