/// <summary>
/// 通过公钥或私钥创建RSA，出错抛异常
/// </summary>
public RSA(string key)
{
if (!key.StartsWith("<"))
{
RSAObject = RsaPem.FromPEM(key).GetRSA();
}
else
{
//var rsaParams = new CspParameters
//{
// Flags = CspProviderFlags.UseMachineKeyStore
//};
RSAObject = new RSACryptoServiceProvider();
RSAObject.FromXmlString(key);
}
}
/// <summary>
/// 通过一个pem对象创建RSA，pem为公钥或私钥，出错抛异常
/// </summary>
public RSA(RsaPem pem)
{
RSAObject = pem.GetRSA();
}
/// <summary>
/// 将XML格式密钥转成PEM，支持公钥xml、私钥xml
/// 出错将会抛出异常
/// </summary>
public static RsaPem FromXML(string xml)
{
var rtv = new RsaPem();
var xmlM = XmlExp.Match(xml);
if (!xmlM.Success)
{
throw new Exception("XML内容不符合要求");
}
var tagM = XmlTagExp.Match(xmlM.Groups[1].Value);
while (tagM.Success)
{
string tag = tagM.Groups[1].Value;
string b64 = tagM.Groups[2].Value;
byte[] val = Convert.FromBase64String(b64);
switch (tag)
{
case "Modulus":
rtv.KeyModulus = val;
break;
case "Exponent":
rtv.KeyExponent = val;
break;
case "D":
rtv.KeyD = val;
break;
case "P":
rtv.ValP = val;
break;
case "Q":
rtv.ValQ = val;
break;
case "DP":
rtv.ValDp = val;
break;
case "DQ":
rtv.ValDq = val;
break;
case "InverseQ":
rtv.ValInverseQ = val;
break;
}
tagM = tagM.NextMatch();
}
if (rtv.KeyModulus == null || rtv.KeyExponent == null)
{
throw new Exception("XML公钥丢失");
}
if (rtv.KeyD != null)
{
if (rtv.ValP == null || rtv.ValQ == null || rtv.ValDp == null || rtv.ValDq == null || rtv.ValInverseQ == null)
{
return(new RsaPem(rtv.KeyModulus, rtv.KeyExponent, rtv.KeyD));
}
}
return(rtv);
}
/// <summary>
/// 用PEM格式密钥对创建RSA，支持PKCS#1、PKCS#8格式的PEM
/// 出错将会抛出异常
/// </summary>
public static RsaPem FromPEM(string pem)
{
RsaPem param = new RsaPem();
var base64 = PemCode.Replace(pem, "");
byte[] data = null;
try
{
data = Convert.FromBase64String(base64);
}
catch
{
}
if (data == null)
{
throw new Exception("PEM内容无效");
}
var idx = 0;
//读取长度
Func <byte, int> readLen = (first) =>
{
if (data[idx] == first)
{
idx++;
if (data[idx] == 0x81)
{
idx++;
return(data[idx++]);
}
if (data[idx] == 0x82)
{
idx++;
return(((data[idx++]) << 8) + data[idx++]);
}
if (data[idx] < 0x80)
{
return(data[idx++]);
}
}
throw new Exception("PEM未能提取到数据");
};
//读取块数据
Func <byte[]> readBlock = () =>
{
var len = readLen(0x02);
if (data[idx] == 0x00)
{
idx++;
len--;
}
var val = new byte[len];
for (var i = 0; i < len; i++)
{
val[i] = data[idx + i];
}
idx += len;
return(val);
};
//比较data从idx位置开始是否是byts内容
Func <byte[], bool> eq = (byts) =>
{
for (var i = 0; i < byts.Length; i++, idx++)
{
if (idx >= data.Length)
{
return(false);
}
if (byts[i] != data[idx])
{
return(false);
}
}
return(true);
};
if (pem.Contains("PUBLIC KEY"))
{
//使用公钥
//读取数据总长度
readLen(0x30);
//看看有没有oid
var idx2 = idx;
if (eq(SeqOid))
{
//读取1长度
readLen(0x03);
idx++; //跳过0x00
//读取2长度
readLen(0x30);
}
else
{
idx = idx2;
}
//Modulus
param.KeyModulus = readBlock();
//Exponent
param.KeyExponent = readBlock();
}
else if (pem.Contains("PRIVATE KEY"))
{
//使用私钥
//读取数据总长度
readLen(0x30);
//读取版本号
if (!eq(Ver))
{
throw new Exception("PEM未知版本");
}
//检测PKCS8
var idx2 = idx;
if (eq(SeqOid))
{
//读取1长度
readLen(0x04);
//读取2长度
readLen(0x30);
//读取版本号
if (!eq(Ver))
{
throw new Exception("PEM版本无效");
}
}
else
{
idx = idx2;
}
//读取数据
param.KeyModulus = readBlock();
param.KeyExponent = readBlock();
param.KeyD = readBlock();
param.ValP = readBlock();
param.ValQ = readBlock();
param.ValDp = readBlock();
param.ValDq = readBlock();
param.ValInverseQ = readBlock();
}
else
{
throw new Exception("pem需要BEGIN END标头");
}
return(param);
}
