public class RSAHelper
{
private readonly RSA _privateKeyRsaProvider;
private readonly RSA _publicKeyRsaProvider;
private readonly HashAlgorithmName _hashAlgorithmName;
private readonly Encoding _encoding;
protected static readonly ILogger _logger = LogManager.GetCurrentClassLogger();
///
/// 实例化RSAHelper
///
/// 加密算法类型 RSA SHA1;RSA2 SHA256 密钥长度至少为2048
/// 编码类型
/// 私钥
/// 公钥
public RSAHelper(RSAType rsaType, Encoding encoding, string privateKey, string publicKey = null)
{
_encoding = encoding;
if (!string.IsNullOrEmpty(privateKey))
{
_privateKeyRsaProvider = CreateRsaProviderFromPrivateKey(privateKey);
}
if (!string.IsNullOrEmpty(publicKey))
{
_publicKeyRsaProvider = CreateRsaProviderFromPublicKey(publicKey);
}
_hashAlgorithmName = rsaType == RSAType.RSA ? HashAlgorithmName.SHA1 : HashAlgorithmName.SHA256;
}
#region 使用私钥签名
///
/// 使用私钥签名
///
/// 原始数据
///
public string Sign(string data)
{
byte[] dataBytes = _encoding.GetBytes(data);
var signatureBytes = _privateKeyRsaProvider.SignData(dataBytes, _hashAlgorithmName, RSASignaturePadding.Pkcs1);
return Convert.ToBase64String(signatureBytes);
}
#endregion
#region 使用公钥验证签名
///
/// 使用公钥验证签名
///
/// 原始数据
/// 签名
///
public bool Verify(string data, string sign)
{
byte[] dataBytes = _encoding.GetBytes(data);
byte[] signBytes = Convert.FromBase64String(sign);
var verify = _publicKeyRsaProvider.VerifyData(dataBytes, signBytes, _hashAlgorithmName, RSASignaturePadding.Pkcs1);
return verify;
}
#endregion
#region 解密
public string Decrypt(string cipherText)
{
if (_privateKeyRsaProvider == null)
{
_logger.Error("_privateKeyRsaProvider is null");
throw new Exception("_privateKeyRsaProvider is null");
}
return Encoding.UTF8.GetString(_privateKeyRsaProvider.Decrypt(Convert.FromBase64String(cipherText), RSAEncryptionPadding.Pkcs1));
}
#endregion
#region 加密
public string Encrypt(string text)
{
if (_publicKeyRsaProvider == null)
{
_logger.Error("_publicKeyRsaProvider is null");
throw new Exception("_publicKeyRsaProvider is null");
}
return Convert.ToBase64String(_publicKeyRsaProvider.Encrypt(Encoding.UTF8.GetBytes(text), RSAEncryptionPadding.Pkcs1));
}
#endregion
#region 使用私钥创建RSA实例
public RSA CreateRsaProviderFromPrivateKey(string privateKey)
{
var privateKeyBits = Convert.FromBase64String(privateKey);
var rsa = RSA.Create();
var rsaParameters = new RSAParameters();
using (BinaryReader 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
{
_logger.Error("Unexpected value read binr.ReadUInt16()");
throw new Exception("Unexpected value read binr.ReadUInt16()");
}
twobytes = binr.ReadUInt16();
if (twobytes != 0x0102)
{
_logger.Error("Unexpected version");
throw new Exception("Unexpected version");
}
bt = binr.ReadByte();
if (bt != 0x00)
{
_logger.Error("Unexpected value read binr.ReadByte()");
throw new Exception("Unexpected value read binr.ReadByte()");
}
rsaParameters.Modulus = binr.ReadBytes(GetIntegerSize(binr));
rsaParameters.Exponent = binr.ReadBytes(GetIntegerSize(binr));
rsaParameters.D = binr.ReadBytes(GetIntegerSize(binr));
rsaParameters.P = binr.ReadBytes(GetIntegerSize(binr));
rsaParameters.Q = binr.ReadBytes(GetIntegerSize(binr));
rsaParameters.DP = binr.ReadBytes(GetIntegerSize(binr));
rsaParameters.DQ = binr.ReadBytes(GetIntegerSize(binr));
rsaParameters.InverseQ = binr.ReadBytes(GetIntegerSize(binr));
}
rsa.ImportParameters(rsaParameters);
return rsa;
}
#endregion
#region 使用公钥创建RSA实例
public RSA CreateRsaProviderFromPublicKey(string publicKeyString)
{
// encoded OID sequence for PKCS #1 rsaEncryption szOID_RSA_RSA = "1.2.840.113549.1.1.1"
byte[] seqOid = { 0x30, 0x0D, 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01, 0x05, 0x00 };
byte[] seq = new byte[15];
var x509Key = Convert.FromBase64String(publicKeyString);
// --------- Set up stream to read the asn.1 encoded SubjectPublicKeyInfo blob ------
using (MemoryStream mem = new MemoryStream(x509Key))
{
using (BinaryReader binr = new BinaryReader(mem)) //wrap Memory Stream with BinaryReader for easy reading
{
byte bt = 0;
ushort twobytes = 0;
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;
seq = binr.ReadBytes(15); //read the Sequence OID
if (!CompareBytearrays(seq, seqOid)) //make sure Sequence for OID is correct
return null;
twobytes = binr.ReadUInt16();
if (twobytes == 0x8103) //data read as little endian order (actual data order for Bit String is 03 81)
binr.ReadByte(); //advance 1 byte
else if (twobytes == 0x8203)
binr.ReadInt16(); //advance 2 bytes
else
return null;
bt = binr.ReadByte();
if (bt != 0x00) //expect null byte next
return null;
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();
byte lowbyte = 0x00;
byte highbyte = 0x00;
if (twobytes == 0x8102) //data read as little endian order (actual data order for Integer is 02 81)
lowbyte = binr.ReadByte(); // read next bytes which is bytes in modulus
else if (twobytes == 0x8202)
{
highbyte = binr.ReadByte(); //advance 2 bytes
lowbyte = binr.ReadByte();
}
else
return null;
byte[] modint = { lowbyte, highbyte, 0x00, 0x00 }; //reverse byte order since asn.1 key uses big endian order
int modsize = BitConverter.ToInt32(modint, 0);
int firstbyte = binr.PeekChar();
if (firstbyte == 0x00)
{ //if first byte (highest order) of modulus is zero, don't include it
binr.ReadByte(); //skip this null byte
modsize -= 1; //reduce modulus buffer size by 1
}
byte[] modulus = binr.ReadBytes(modsize); //read the modulus bytes
if (binr.ReadByte() != 0x02) //expect an Integer for the exponent data
return null;
int expbytes = (int)binr.ReadByte(); // should only need one byte for actual exponent data (for all useful values)
byte[] exponent = binr.ReadBytes(expbytes);
// ------- create RSACryptoServiceProvider instance and initialize with public key -----
var rsa = RSA.Create();
RSAParameters rsaKeyInfo = new RSAParameters
{
Modulus = modulus,
Exponent = exponent
};
rsa.ImportParameters(rsaKeyInfo);
return rsa;
}
}
}
#endregion
#region 导入密钥算法
private int GetIntegerSize(BinaryReader binr)
{
byte bt = 0;
int count = 0;
bt = binr.ReadByte();
if (bt != 0x02)
return 0;
bt = binr.ReadByte();
if (bt == 0x81)
count = binr.ReadByte();
else
if (bt == 0x82)
{
var highbyte = binr.ReadByte();
var 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 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;
}
#endregion
}
///
/// RSA算法类型
///
public enum RSAType
{
///
/// SHA1
///
RSA = 0,
///
/// RSA2 密钥长度至少为2048
/// SHA256
///
RSA2
}