.net core 中使用 openssl 公钥私钥进行加解密
这篇博文分享的是 C#中使用OpenSSL的公钥加密/私钥解密 一文中的解决方法在 .net core 中的改进。之前的博文针对的是 .NET Framework ，加解密用的是 RSACryptoServiceProvider 。虽然在 corefx(.NET Core Framework) 中也有 RSACryptoServiceProvider ，但它目前只支持 Windows ，不能跨平台。
之前的 new RSACryptoServiceProvider(); 代码在 mac 上运行，会报下面的错误：
System.PlatformNotSupportedException: Operation is not supported on this platform. at System.Security.Cryptography.RSACryptoServiceProvider..ctor()
要解决这个问题，需要改用 System.Security.Cryptography.RSA.Create() 工厂方法，使用它之后，在 Windows 上创建的是 System.Security.Cryptography.RSACng 的实例，在 Mac 与 Linux 上创建的是 System.Security.Cryptography.RSAOpenSsl 的实例，它们都继承自 System.Security.Cryptography.RSA 抽象类。
使用了 RSA.Create() 之后，带来了一个问题，RSA 中没有 RSACryptoServiceProvider 中的以下2个签名的加解密方法。
public byte[] Encrypt(byte[] rgb, bool fOAEP); public byte[] Decrypt(byte[] rgb, bool fOAEP);
只有
public abstract byte[] Encrypt(byte[] data, RSAEncryptionPadding padding); public abstract byte[] Decrypt(byte[] data, RSAEncryptionPadding padding);
调用时它们时需要传递 RSAEncryptionPadding 类型的参数值：
但对于 openssl 生成的公钥私钥不知道选择哪种 RSAEncryptionPadding ，只能采取笨方法 —— 一个一个试试，试出来的结果是 RSAEncryptionPadding.Pkcs1 。
openssl 的公钥与私钥是在 Mac 上通过下面的2个命令生成的：
openssl genrsa -out rsa_1024_priv.pem 102 openssl rsa -pubout -in rsa_1024_priv.pem -out rsa_1024_pub.pem
（注：一定要用 openssl 命令，用 ssh-keygen -t rsa 命令生成的公钥私钥是不行的）
修改这两个地方（RSA.Create 与 RSAEncryptionPadding.Pkcs1）之后，就可以在 .net core 上使用 openssl 的公钥私钥进行加解密了，以下是测试时所用的完整代码（.net core控制台程序）。经测试，在 Windows，macOS，Linux Ubuntu 上都能成功进行加解密。
Program.cs
using System; using System.IO; using System.Security.Cryptography; using System.Text; namespace TryRsa { public class Program { //openssl genrsa -out rsa_1024_priv.pem 1024 private static readonly string _privateKey = @"MIICXgIBAAKBgQC0xP5HcfThSQr43bAMoopbzcCyZWE0xfUeTA4Nx4PrXEfDvybJ EIjbU/rgANAty1yp7g20J7+wVMPCusxftl/d0rPQiCLjeZ3HtlRKld+9htAZtHFZ osV29h/hNE9JkxzGXstaSeXIUIWquMZQ8XyscIHhqoOmjXaCv58CSRAlAQIDAQAB AoGBAJtDgCwZYv2FYVk0ABw6F6CWbuZLUVykks69AG0xasti7Xjh3AximUnZLefs iuJqg2KpRzfv1CM+Cw5cp2GmIVvRqq0GlRZGxJ38AqH9oyUa2m3TojxWapY47zye PYEjWwRTGlxUBkdujdcYj6/dojNkm4azsDXl9W5YaXiPfbgJAkEA4rlhSPXlohDk FoyfX0v2OIdaTOcVpinv1jjbSzZ8KZACggjiNUVrSFV3Y4oWom93K5JLXf2mV0Sy 80mPR5jOdwJBAMwciAk8xyQKpMUGNhFX2jKboAYY1SJCfuUnyXHAPWeHp5xCL2UH tjryJp/Vx8TgsFTGyWSyIE9R8hSup+32rkcCQBe+EAkC7yQ0np4Z5cql+sfarMMm 4+Z9t8b4N0a+EuyLTyfs5Dtt5JkzkggTeuFRyOoALPJP0K6M3CyMBHwb7WsCQQCi TM2fCsUO06fRQu8bO1A1janhLz3K0DU24jw8RzCMckHE7pvhKhCtLn+n+MWwtzl/ L9JUT4+BgxeLepXtkolhAkEA2V7er7fnEuL0+kKIjmOm5F3kvMIDh9YC1JwLGSvu 1fnzxK34QwSdxgQRF1dfIKJw73lClQpHZfQxL/2XRG8IoA==".Replace("\n", ""); //openssl rsa -pubout -in rsa_1024_priv.pem -out rsa_1024_pub.pem private static readonly string _publicKey = @"MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC0xP5HcfThSQr43bAMoopbzcCy ZWE0xfUeTA4Nx4PrXEfDvybJEIjbU/rgANAty1yp7g20J7+wVMPCusxftl/d0rPQ iCLjeZ3HtlRKld+9htAZtHFZosV29h/hNE9JkxzGXstaSeXIUIWquMZQ8XyscIHh qoOmjXaCv58CSRAlAQIDAQAB".Replace("\n", ""); public static void Main(string[] args) { var plainText = "cnblogs.com"; //Encrypt RSA rsa = CreateRsaFromPublicKey(_publicKey); var plainTextBytes = Encoding.UTF8.GetBytes(plainText); var cipherBytes = rsa.Encrypt(plainTextBytes, RSAEncryptionPadding.Pkcs1); var cipher = Convert.ToBase64String(cipherBytes); Console.WriteLine($"{nameof(cipher)}:{cipher}"); //Decrypt rsa = CreateRsaFromPrivateKey(_privateKey); cipherBytes = System.Convert.FromBase64String(cipher); plainTextBytes = rsa.Decrypt(cipherBytes, RSAEncryptionPadding.Pkcs1); plainText = Encoding.UTF8.GetString(plainTextBytes); Console.WriteLine($"{nameof(plainText)}:{plainText}"); } private static RSA CreateRsaFromPrivateKey(string privateKey) { var privateKeyBits = System.Convert.FromBase64String(privateKey); var rsa = RSA.Create(); var RSAparams = new RSAParameters(); using (var binr = new BinaryReader(new MemoryStream(privateKeyBits))) { byte bt = 0; ushort twobytes = 0; twobytes = binr.ReadUInt16(); if (twobytes == 0x8130) binr.ReadByte(); else if (twobytes == 0x8230) binr.ReadInt16(); else throw new Exception("Unexpected value read binr.ReadUInt16()"); twobytes = binr.ReadUInt16(); if (twobytes != 0x0102) throw new Exception("Unexpected version"); bt = binr.ReadByte(); if (bt != 0x00) throw new Exception("Unexpected value read binr.ReadByte()"); RSAparams.Modulus = binr.ReadBytes(GetIntegerSize(binr)); RSAparams.Exponent = binr.ReadBytes(GetIntegerSize(binr)); RSAparams.D = binr.ReadBytes(GetIntegerSize(binr)); RSAparams.P = binr.ReadBytes(GetIntegerSize(binr)); RSAparams.Q = binr.ReadBytes(GetIntegerSize(binr)); RSAparams.DP = binr.ReadBytes(GetIntegerSize(binr)); RSAparams.DQ = binr.ReadBytes(GetIntegerSize(binr)); RSAparams.InverseQ = binr.ReadBytes(GetIntegerSize(binr)); } rsa.ImportParameters(RSAparams); return rsa; } private static int GetIntegerSize(BinaryReader binr) { byte bt = 0; byte lowbyte = 0x00; byte highbyte = 0x00; int count = 0; bt = binr.ReadByte(); if (bt != 0x02) return 0; bt = binr.ReadByte(); if (bt == 0x81) count = binr.ReadByte(); else if (bt == 0x82) { highbyte = binr.ReadByte(); lowbyte = binr.ReadByte(); byte[] modint = { lowbyte, highbyte, 0x00, 0x00 }; count = BitConverter.ToInt32(modint, 0); } else { count = bt; } while (binr.ReadByte() == 0x00) { count -= 1; } binr.BaseStream.Seek(-1, SeekOrigin.Current); return count; } private static RSA CreateRsaFromPublicKey(string publicKeyString) { 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 = Convert.FromBase64String(publicKeyString); x509size = x509key.Length; using (var mem = new MemoryStream(x509key)) { using (var 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); var rsa = RSA.Create(); var rsaKeyInfo = new RSAParameters { Modulus = modulus, Exponent = exponent }; rsa.ImportParameters(rsaKeyInfo); return rsa; } } } 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; } } }
project.json
{
"version": "1.0.0-*",
"buildOptions": {
"emitEntryPoint": true
},
"dependencies": {
"Microsoft.NETCore.App": {
"type": "platform",
"version": "1.1.0-preview1-001100-00"
},
"System.Security.Cryptography.Algorithms": "4.3.0-preview1-24530-04"
},
"frameworks": {
"netcoreapp1.1": {
"imports": "dnxcore50"
}
}
}
相关链接
【更新】
如果遇到解密时遇到"Bad Data"的问题：
System.Security.Cryptography.CryptographicException: Bad Data.
可以使用下面的方法（同事实现的代码）：
public string Decrypt(string cipher) { return Encoding.UTF8.GetString(_rsa.Decrypt(Convert.FromBase64String(cipher), RSAEncryptionPadding.Pkcs1)); var cipherLength = _rsa.KeySize / 8; var cipherBytes = Convert.FromBase64String(cipher); if (cipherBytes.Length < cipherLength) { var delta = cipherLength - cipherBytes.Length; var newBytes = new byte[cipherLength]; Array.Copy(cipherBytes, 0, newBytes, delta, cipherBytes.Length); cipherBytes = newBytes; } return Encoding.UTF8.GetString(_rsa.Decrypt(cipherBytes, RSAEncryptionPadding.Pkcs1)); }
