加密解析：
//假设私钥长度为1024， 1024/8-11=117。
//如果明文的长度小于117，直接全加密，然后转base64。(data.Length <= maxBlockSize)
//如果明文长度大于117，则每117分一段加密，写入到另一个Stream中，最后转base64。while (blockSize > 0)
如果要和其它语言互通，这个分段长度需要和其它语言约定好，不一是 私钥长度/8-11。
解密解析：
//假设私钥长度为1024， 1024/8 =128。
//如果明文的长度小于 128，直接全解密。(data.Length <= maxBlockSize)
//如果明文长度大于 128，则每 128 分一段解密，写入到另一个Stream中，最后 GetString。while (blockSize > 0)
核心重点是拿到 .NET 的RSACryptoServiceProvider 对象。
nuget 中引用 Portable.BouncyCastle。
工具类：
RsaUtil：
using Org.BouncyCastle.Crypto.Parameters; using Org.BouncyCastle.Security; using System; using System.IO; using System.Security.Cryptography; using System.Security.Cryptography.X509Certificates; namespace CommonUtils { public static class RsaUtil { #region 加载私钥 /// <summary> /// 转换私钥字符串为RSACryptoServiceProvider /// </summary> /// <param name="privateKeyStr">私钥字符串</param> /// <param name="keyFormat">PKCS8,PKCS1</param> /// <param name="signType">RSA 私钥长度1024 ,RSA2 私钥长度2048</param> /// <returns></returns> public static RSACryptoServiceProvider LoadPrivateKey(string privateKeyStr, string keyFormat) { string signType = "RSA"; if (privateKeyStr.Length > 1024) { signType = "RSA2"; } //PKCS8,PKCS1 if (keyFormat == "PKCS1") { return LoadPrivateKeyPKCS1(privateKeyStr, signType); } else { return LoadPrivateKeyPKCS8(privateKeyStr); } } /// <summary> /// PKCS1 格式私钥转 RSACryptoServiceProvider 对象 /// </summary> /// <param name="strKey">pcsk1 私钥的文本内容</param> /// <param name="signType">RSA 私钥长度1024 ,RSA2 私钥长度2048 </param> /// <returns></returns> public static RSACryptoServiceProvider LoadPrivateKeyPKCS1(string privateKeyPemPkcs1, string signType) { try { privateKeyPemPkcs1 = privateKeyPemPkcs1.Replace("-----BEGIN RSA PRIVATE KEY-----", "").Replace("-----END RSA PRIVATE KEY-----", "").Replace("\r", "").Replace("\n", "").Trim(); privateKeyPemPkcs1 = privateKeyPemPkcs1.Replace("-----BEGIN PRIVATE KEY-----", "").Replace("-----END PRIVATE KEY-----", "").Replace("\r", "").Replace("\n", "").Trim(); byte[] data = null; //读取带 data = Convert.FromBase64String(privateKeyPemPkcs1); RSACryptoServiceProvider rsa = DecodeRSAPrivateKey(data, signType); return rsa; } catch (Exception ex) { throw ex; } return null; } private static RSACryptoServiceProvider DecodeRSAPrivateKey(byte[] privkey, string signType) { 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; int bitLen = 1024; if ("RSA2".Equals(signType)) { bitLen = 2048; } RSACryptoServiceProvider RSA = new RSACryptoServiceProvider(bitLen, CspParameters); //RSACryptoServiceProvider RSA = new RSACryptoServiceProvider(); 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) { throw 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; } /// <summary> /// PKCS8 文本转RSACryptoServiceProvider 对象 /// </summary> /// <param name="privateKeyPemPkcs8"></param> /// <returns></returns> public static RSACryptoServiceProvider LoadPrivateKeyPKCS8(string privateKeyPemPkcs8) { try { //PKCS8是“BEGIN PRIVATE KEY” privateKeyPemPkcs8 = privateKeyPemPkcs8.Replace("-----BEGIN RSA PRIVATE KEY-----", "").Replace("-----END RSA PRIVATE KEY-----", "").Replace("\r", "").Replace("\n", "").Trim(); privateKeyPemPkcs8 = privateKeyPemPkcs8.Replace("-----BEGIN PRIVATE KEY-----", "").Replace("-----END PRIVATE KEY-----", "").Replace("\r", "").Replace("\n", "").Trim(); //pkcs8 文本先转为 .NET XML 私钥字符串 string privateKeyXml = RSAPrivateKeyJava2DotNet(privateKeyPemPkcs8); RSACryptoServiceProvider publicRsa = new RSACryptoServiceProvider(); publicRsa.FromXmlString(privateKeyXml); return publicRsa; } catch (Exception ex) { throw ex; } } /// <summary> /// PKCS8 私钥文本 转 .NET XML 私钥文本 /// </summary> /// <param name="privateKeyPemPkcs8"></param> /// <returns></returns> public static string RSAPrivateKeyJava2DotNet(string privateKeyPemPkcs8) { RsaPrivateCrtKeyParameters privateKeyParam = (RsaPrivateCrtKeyParameters)PrivateKeyFactory.CreateKey(Convert.FromBase64String(privateKeyPemPkcs8)); 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())); } #endregion /// <summary> /// 加载公钥证书 /// </summary> /// <param name="publicKeyCert">公钥证书文本内容</param> /// <returns></returns> public static RSACryptoServiceProvider LoadPublicCert(string publicKeyCert) { publicKeyCert = publicKeyCert.Replace("-----BEGIN CERTIFICATE-----", "").Replace("-----END CERTIFICATE-----", "").Replace("\r", "").Replace("\n", "").Trim(); byte[] bytesCerContent = Convert.FromBase64String(publicKeyCert); X509Certificate2 x509 = new X509Certificate2(bytesCerContent); RSACryptoServiceProvider rsaPub = (RSACryptoServiceProvider)x509.PublicKey.Key; return rsaPub; } /// <summary> /// pem 公钥文本 转 .NET RSACryptoServiceProvider。 /// </summary> /// <param name="publicKeyPem"></param> /// <returns></returns> public static RSACryptoServiceProvider LoadPublicKey(string publicKeyPem) { publicKeyPem = publicKeyPem.Replace("-----BEGIN PUBLIC KEY-----", "").Replace("-----END PUBLIC KEY-----", "").Replace("\r", "").Replace("\n", "").Trim(); //pem 公钥文本 转 .NET XML 公钥文本。 string publicKeyXml = RSAPublicKeyJava2DotNet(publicKeyPem); RSACryptoServiceProvider publicRsa = new RSACryptoServiceProvider(); publicRsa.FromXmlString(publicKeyXml); return publicRsa; } /// <summary> /// pem 公钥文本 转 .NET XML 公钥文本。 /// </summary> /// <param name="publicKey"></param> /// <returns></returns> private 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())); } } }
RsaEncryptUtil：
using Org.BouncyCastle.Crypto; using Org.BouncyCastle.Crypto.Parameters; using Org.BouncyCastle.Security; using System; using System.IO; using System.Security.Cryptography; using System.Text; namespace CommonUtils { public static class RsaEncryptUtil { #region 非标准的-私钥加密-公钥解密 /// <summary> /// 私钥加密 .Net平台默认是使用公钥进行加密，私钥进行解密。私钥加密需要自己实现或者使用第三方dll /// </summary> /// <param name="data"></param> /// <param name="key">私钥,格式:PKCS8</param> /// <returns></returns> public static byte[] encryptByPrivateKey(String data, String key) { String priKey = key.Trim(); String xmlPrivateKey = RSAPrivateKeyJava2DotNet(priKey); //加载私钥 RSACryptoServiceProvider privateRsa = new RSACryptoServiceProvider(); privateRsa.FromXmlString(xmlPrivateKey); //转换密钥 AsymmetricCipherKeyPair keyPair = DotNetUtilities.GetKeyPair(privateRsa); IBufferedCipher c = CipherUtilities.GetCipher("RSA/ECB/PKCS1Padding");// 参数与Java中加密解密的参数一致 c.Init(true, keyPair.Private); //第一个参数为true表示加密，为false表示解密；第二个参数表示密钥 byte[] DataToEncrypt = Encoding.UTF8.GetBytes(data); byte[] outBytes = c.DoFinal(DataToEncrypt);//加密 return outBytes; } /// <summary> /// 私钥加密 /// </summary> /// <param name="data">明文</param> /// <param name="key">私钥</param> /// <param name="keyFormat">私钥格式:PKCS1,PKCS8</param> /// <returns></returns> public static byte[] encryptByPrivateKey(String data, String key, string keyFormat) { String priKey = key.Trim(); //加载私钥 RSACryptoServiceProvider privateRsa = RsaUtil.LoadPrivateKey(key, keyFormat); //转换密钥 AsymmetricCipherKeyPair keyPair = DotNetUtilities.GetKeyPair(privateRsa); IBufferedCipher c = CipherUtilities.GetCipher("RSA/ECB/PKCS1Padding");// 参数与Java中加密解密的参数一致 c.Init(true, keyPair.Private); //第一个参数为true表示加密，为false表示解密；第二个参数表示密钥 byte[] DataToEncrypt = Encoding.UTF8.GetBytes(data); byte[] outBytes = c.DoFinal(DataToEncrypt);//加密 return outBytes; } /// <summary> /// RSA私钥格式转换，java->.net /// </summary> /// <param name="privateKey"></param> /// <returns></returns> private 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> /// 用公钥解密 /// </summary> /// <param name="data"></param> /// <param name="key"></param> /// <returns></returns> public static byte[] decryptByPublicKey(String data, String key) { String pubKey = key.Trim(); String xmlPublicKey = RSAPublicKeyJava2DotNet(pubKey); RSACryptoServiceProvider publicRsa = new RSACryptoServiceProvider(); publicRsa.FromXmlString(xmlPublicKey); AsymmetricKeyParameter keyPair = DotNetUtilities.GetRsaPublicKey(publicRsa); //转换密钥 // AsymmetricCipherKeyPair keyPair = DotNetUtilities.GetRsaKeyPair(publicRsa); IBufferedCipher c = CipherUtilities.GetCipher("RSA/ECB/PKCS1Padding");// 参数与Java中加密解密的参数一致 c.Init(false, keyPair); //第一个参数为true表示加密，为false表示解密；第二个参数表示密钥 byte[] DataToEncrypt = Convert.FromBase64String(data); byte[] outBytes = c.DoFinal(DataToEncrypt);//解密 return outBytes; } /// <summary> /// RSA公钥格式转换，java->.net /// </summary> /// <param name="publicKey"></param> /// <returns></returns> private 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())); } #endregion #region 标准的-公钥加密-私钥解密 /** 默认编码字符集 */ private static string DEFAULT_CHARSET = "UTF-8"; /// <summary> /// 公钥加密（超过 私钥长度 / 8 - 11，分段加密） /// </summary> /// <param name="content">明文</param> /// <param name="charset">编码</param> /// <param name="publicKeyPem">公钥</param> /// <returns></returns> /// <exception cref="Exception"></exception> public static string RSAEncrypt(string content, string charset, string publicKeyPem) { try { //假设私钥长度为1024， 1024/8-11=117。 //如果明文的长度小于117，直接全加密，然后转base64。(data.Length <= maxBlockSize) //如果明文长度大于117，则每117分一段加密，写入到另一个Stream中，最后转base64。while (blockSize > 0) RSACryptoServiceProvider rsa = RsaUtil.LoadPublicKey(publicKeyPem); //string sPublicKeyPEM = File.ReadAllText(publicKeyPem); //RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(); //rsa.PersistKeyInCsp = false; //RSACryptoServiceProviderExtension.LoadPublicKeyPEM(rsa, sPublicKeyPEM); if (string.IsNullOrEmpty(charset)) { charset = DEFAULT_CHARSET; } byte[] data = Encoding.GetEncoding(charset).GetBytes(content); int maxBlockSize = rsa.KeySize / 8 - 11; //加密块最大长度限制 if (data.Length <= maxBlockSize) { byte[] cipherbytes = rsa.Encrypt(data, false); return Convert.ToBase64String(cipherbytes); } MemoryStream plaiStream = new MemoryStream(data); MemoryStream crypStream = new MemoryStream(); Byte[] buffer = new Byte[maxBlockSize]; int blockSize = plaiStream.Read(buffer, 0, maxBlockSize); while (blockSize > 0) { Byte[] toEncrypt = new Byte[blockSize]; Array.Copy(buffer, 0, toEncrypt, 0, blockSize); Byte[] cryptograph = rsa.Encrypt(toEncrypt, false); crypStream.Write(cryptograph, 0, cryptograph.Length); blockSize = plaiStream.Read(buffer, 0, maxBlockSize); } return Convert.ToBase64String(crypStream.ToArray(), Base64FormattingOptions.None); } catch (Exception ex) { throw new Exception("EncryptContent = " + content + ",charset = " + charset, ex); } } /// <summary> /// 私钥解密（超过 私钥长度 / 8 - 11，分段加密） /// </summary> /// <param name="content">密文</param> /// <param name="charset">编码</param> /// <param name="privateKeyPem">私钥</param> /// <param name="keyFormat">私钥格式 PKCS1,PKCS8</param> /// <returns></returns> /// <exception cref="Exception"></exception> public static string RSADecrypt(string content, string charset, string privateKeyPem, string keyFormat) { try { //假设私钥长度为1024， 1024/8 =128。 //如果明文的长度小于 128，直接全解密。(data.Length <= maxBlockSize) //如果明文长度大于 128，则每 128 分一段解密，写入到另一个Stream中，最后 GetString。while (blockSize > 0) RSACryptoServiceProvider rsaCsp = RsaUtil.LoadPrivateKey(privateKeyPem, keyFormat); //RSACryptoServiceProvider rsaCsp = LoadCertificateFile(privateKeyPem, signType); if (string.IsNullOrEmpty(charset)) { charset = DEFAULT_CHARSET; } byte[] data = Convert.FromBase64String(content); int maxBlockSize = rsaCsp.KeySize / 8; //解密块最大长度限制 if (data.Length <= maxBlockSize) { byte[] cipherbytes = rsaCsp.Decrypt(data, false); return Encoding.GetEncoding(charset).GetString(cipherbytes); } MemoryStream crypStream = new MemoryStream(data); MemoryStream plaiStream = new MemoryStream(); Byte[] buffer = new Byte[maxBlockSize]; int blockSize = crypStream.Read(buffer, 0, maxBlockSize); while (blockSize > 0) { Byte[] toDecrypt = new Byte[blockSize]; Array.Copy(buffer, 0, toDecrypt, 0, blockSize); Byte[] cryptograph = rsaCsp.Decrypt(toDecrypt, false); plaiStream.Write(cryptograph, 0, cryptograph.Length); blockSize = crypStream.Read(buffer, 0, maxBlockSize); } return Encoding.GetEncoding(charset).GetString(plaiStream.ToArray()); } catch (Exception ex) { throw new Exception("DecryptContent = " + content + ",charset = " + charset, ex); } } #endregion } }
使用：
支持超出 私钥长度/8 -11 的长度明文，分段加密。
公钥加密：
private void btnPubKeyEncrypt_Click(object sender, EventArgs e) { try { string rst = RsaEncryptUtil.RSAEncrypt(txtMingWen.Text, "UTF-8", txtPubKey.Text); txtJiaMiHou.Text = rst; } catch (Exception ex) { MessageBox.Show(ex.Message); } }
私钥解密 ：
private void btnPrivateKeyDecrypt_Click(object sender, EventArgs e) { try { string strRst = RsaEncryptUtil.RSADecrypt(txtJiaMiHou.Text, "UTF-8", txtPrivateKey.Text, cbxPrivateKeyFormat.Text); txtJieMiHou.Text = strRst; } catch (Exception ex) { MessageBox.Show(ex.Message); } }
end