我读取.der文件如下。
byte[] byteKey = File.ReadAllBytes(openFileDialog1.FileName);
X509Certificate2 cert = new X509Certificate2(byteKey);
但它没有私钥。它只有公钥。
cert.HasPrivateKey 返回 false。
当我搜索它时，我发现'.der文件没有私钥，私钥在.key文件中'。
我用记事本++打开了一个和.der文件同路径的.key文件，会打印断掉的文字。
第一个问题，如何在 C# 上从 .key 文件中读取私钥？
第二，如何在 C# 上将 .key 文件转换为 .pem 文件？ 只是用openssl吗？
感谢您的教导。
【问题讨论】：
.key 文件是证书。请创建文件的人给你一个格式。很可能是带有密码的 PKCS #8。
.NET 的当前版本在这里没有很好的故事。 .NET Core 3.0 有一个更好的故事。如果您愿意使用名称中带有“Experimental”的 NuGet 包，那么还有一个更好的故事。
注意：在整个答案中，我不会考虑像 BouncyCastle 这样的第三方库。它可能会完美地满足您的需求，但这不是我的专业领域。当我知道 NuGet 包时，我会考虑由同一组人开发的 .NET 收件箱库。
没有办法。
没有一个单一的答案，您需要知道您拥有什么样的文件（或者只是尝试所有答案）。
这些方法需要注意的是，它们仅了解 BER/DER 数据，而不了解 PEM 数据。因此，如果您的文件是 PEM 格式（这使得识别负载应该是什么最容易），您首先需要将其转换为 BER/DER。
对于大多数 PEM 文件来说，这很简单：您只需找到 BEGIN 和 END 标记之间的内容，通过 Convert.FromBase64String 运行它，然后瞧。从技术上讲，PEM 支持属性，并且处理这些属性更难（并且超出了此答案的范围）。
所以，你最终可能会得到类似的东西
RSA rsa = RSA.Create();
try
{
rsa.ImportRSAPrivateKey(data, out _);
return rsa;
}
catch (CryptographicException)
{
}
try
{
rsa.ImportPkcs8PrivateKey(data, out _);
return rsa;
}
catch (CryptographicException)
{
}
try
{
// prompt for password, then
rsa.ImportEncryptedPkcs8PrivateKey(password, data, out _);
return rsa;
}
catch (CryptographicException)
{
}
rsa.Dispose();
ECDsa ecdsa = ECDsa.Create();
...
忽略的out 值是输入字节中使用的字节数。它主要只在从文件中间读取时才相关。
没办法，这个库比那个低很多。
好吧，这并不是问题的真正解释方式，而是一种转义。
加密密钥文件总是（根据我的经验）DER-（尽管偶尔放松为 BER-）编码的 ASN.1 数据结构。要完全理解它们，您需要阅读和理解
这些结构有时会使用隐私增强邮件 (PEM) 语法转换为文本表示，这本质上是
BEGIN 后跟一个空格END 后跟一个空格更多信息请参见RFC 7468。
没有办法。
没有办法。
这个 NuGet 包是 .NET Core 2.1 / 3.0 公开的 ASN.1 阅读器（想法是在一些可用性反馈后从 .NET Core 公开）。
读取一个 RSAPrivateKey，例如：
// PKCS#1 doesn't say that this structure is always DER encoded, so read it as BER
AsnReader reader = new AsnReader(data, AsnEncodingRules.BER);
// RSAPrivateKey ::= SEQUENCE {
AsnReader contents = reader.ReadSequence();
// version Version (0 for two-prime RSA)
if (!contents.TryReadInt32(out int version) || version != 0)
{
throw new CryptographicException();
}
// modulus INTEGER,
BigInteger modulus = contents.ReadInteger();
// publicExponent INTEGER,
BigInteger publicExponent = contents.ReadInteger();
// privateExponent INTEGER,
BigInteger privateExponent = contents.ReadInteger();
// prime1 INTEGER,
BigInteger prime1 = contents.ReadInteger();
// prime2 INTEGER,
BigInteger prime2 = contents.ReadInteger();
// exponent1 INTEGER,
BigInteger exponent1 = contents.ReadInteger();
// exponent2 INTEGER,
BigInteger exponent2 = contents.ReadInteger();
// coefficient INTEGER,
BigInteger coefficient = contents.ReadInteger();
// otherPrimeInfos OtherPrimeInfos OPTIONAL,
// we don't support this, we limited to version 0.
// good thing the next token is:
// }
contents.ThrowIfNotEmpty();
// All done.
// If you expected no trailing data:
reader.ThrowIfNotEmpty();
其他格式也是如此。
【讨论】：
我已经解决了这个问题，但我只能回答你一半。你应该使用openssl打开.key，这是代码（注意：这个代码来自这个codeproject帖子）：
using System;
using System.IO;
using System.Text;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Runtime.InteropServices;
using System.Security;
using System.Diagnostics;
using System.ComponentModel;
namespace OpenSSL
{
public class opensslkey
{
public string SignString(string pKeyFile,string pPassword,string OriginalString)
{
string SignedString = "";
string filename = pKeyFile;
if (!File.Exists(filename))
{
return ".key file does not exist " + pKeyFile;
}
RSACryptoServiceProvider rsa=OpenKeyFile(filename, pPassword);
if (rsa != null)
{
byte[] CO=Encoding.UTF8.GetBytes(OriginalString);
byte[] SignedBytes=rsa.SignData(CO, new SHA1CryptoServiceProvider());
SignedString = Convert.ToBase64String(SignedBytes);
}
return SignedString;
}
public RSACryptoServiceProvider OpenKeyFile(String filename,string pPassword)
{
RSACryptoServiceProvider rsa = null;
byte[] keyblob = GetFileBytes(filename);
if (keyblob == null)
return null;
rsa = DecodePrivateKeyInfo(keyblob, pPassword); //PKCS #8 encrypted
if (rsa != null)
{
return rsa;
}
return null;
}
public static RSACryptoServiceProvider
DecodePrivateKeyInfo(byte[] encpkcs8,string pPassword)
{
// encoded OID sequence for PKCS #1 rsaEncryption szOID_RSA_RSA ="1.2.840.113549.1.1.1"
// this byte[] includes the sequence byte and terminal encoded null
byte[] OIDpkcs5PBES2 = { 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x05, 0x0D };
byte[] OIDpkcs5PBKDF2 = { 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x05, 0x0C };
byte[] OIDdesEDE3CBC = { 0x06, 0x08, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x03, 0x07 };
byte[] seqdes = new byte[10];
byte[] seq = new byte[11];
byte[] salt;
byte[] IV;
byte[] encryptedpkcs8;
byte[] pkcs8;
int saltsize, ivsize, encblobsize;
int iterations;
// --------- Set up stream to read the asn.1 encoded SubjectPublicKeyInfo blob ------
MemoryStream mem = new MemoryStream(encpkcs8);
int lenstream = (int)mem.Length;
BinaryReader binr = new BinaryReader(mem); //wrap Memory Stream with BinaryReader for easy reading
byte bt = 0;
ushort twobytes = 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(); //inner sequence
if (twobytes == 0x8130)
binr.ReadByte();
else if (twobytes == 0x8230)
binr.ReadInt16();
seq = binr.ReadBytes(11); //read the Sequence OID
if (!CompareBytearrays(seq, OIDpkcs5PBES2)) //is it a OIDpkcs5PBES2 ?
return null;
twobytes = binr.ReadUInt16(); //inner sequence for pswd salt
if (twobytes == 0x8130)
binr.ReadByte();
else if (twobytes == 0x8230)
binr.ReadInt16();
twobytes = binr.ReadUInt16(); //inner sequence for pswd salt
if (twobytes == 0x8130)
binr.ReadByte();
else if (twobytes == 0x8230)
binr.ReadInt16();
seq = binr.ReadBytes(11); //read the Sequence OID
if (!CompareBytearrays(seq, OIDpkcs5PBKDF2)) //is it a OIDpkcs5PBKDF2 ?
return null;
twobytes = binr.ReadUInt16();
if (twobytes == 0x8130)
binr.ReadByte();
else if (twobytes == 0x8230)
binr.ReadInt16();
bt = binr.ReadByte();
if (bt != 0x04) //expect octet string for salt
return null;
saltsize = binr.ReadByte();
salt = binr.ReadBytes(saltsize);
bt = binr.ReadByte();
if (bt != 0x02) //expect an integer for PBKF2 interation count
return null;
int itbytes = binr.ReadByte(); //PBKD2 iterations should fit in 2 bytes.
if (itbytes == 1)
iterations = binr.ReadByte();
else if (itbytes == 2)
iterations = 256 * binr.ReadByte() + binr.ReadByte();
else
return null;
twobytes = binr.ReadUInt16();
if (twobytes == 0x8130)
binr.ReadByte();
else if (twobytes == 0x8230)
binr.ReadInt16();
seqdes = binr.ReadBytes(10); //read the Sequence OID
if (!CompareBytearrays(seqdes, OIDdesEDE3CBC)) //is it a OIDdes-EDE3-CBC ?
return null;
bt = binr.ReadByte();
if (bt != 0x04) //expect octet string for IV
return null;
ivsize = binr.ReadByte(); // IV byte size should fit in one byte (24 expected for 3DES)
IV = binr.ReadBytes(ivsize);
bt = binr.ReadByte();
if (bt != 0x04) // expect octet string for encrypted PKCS8 data
return null;
bt = binr.ReadByte();
if (bt == 0x81)
encblobsize = binr.ReadByte(); // data size in next byte
else if (bt == 0x82)
encblobsize = 256 * binr.ReadByte() + binr.ReadByte();
else
encblobsize = bt; // we already have the data size
encryptedpkcs8 = binr.ReadBytes(encblobsize);
SecureString secpswd = new SecureString();
foreach (char c in pPassword)
secpswd.AppendChar(c);
pkcs8 = DecryptPBDK2(encryptedpkcs8, salt, IV, secpswd, iterations);
if (pkcs8 == null) // probably a bad pswd entered.
return null;
RSACryptoServiceProvider rsa = DecodePrivateKeyInfo(pkcs8);
return rsa;
}
catch (Exception)
{
return null;
}
finally { binr.Close(); }
}
public void CertificateData(string pCerFile, out string Certificate, out string CertificateNumber)
{
X509Certificate cert = new X509Certificate(pCerFile);
byte[] strcert = cert.GetRawCertData();
Certificate = Convert.ToBase64String(strcert);
strcert = cert.GetSerialNumber();
CertificateNumber = Reverse(System.Text.Encoding.UTF8.GetString(strcert));
}
public string Reverse(string Original)
{
string Reverse = "";
for (int i = Original.Length - 1; i >= 0; i--)
Reverse += Original.Substring(i, 1);
return Reverse;
}
private static byte[] GetFileBytes(String filename)
{
if (!File.Exists(filename))
return null;
Stream stream = new FileStream(filename, FileMode.Open);
int datalen = (int)stream.Length;
byte[] filebytes = new byte[datalen];
stream.Seek(0, SeekOrigin.Begin);
stream.Read(filebytes, 0, datalen);
stream.Close();
return filebytes;
}
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;
}
public static byte[] DecryptPBDK2(byte[] edata, byte[] salt,
byte[] IV, SecureString secpswd, int iterations)
{
CryptoStream decrypt = null;
IntPtr unmanagedPswd = IntPtr.Zero;
byte[] psbytes = new byte[secpswd.Length];
unmanagedPswd = Marshal.SecureStringToGlobalAllocAnsi(secpswd);
Marshal.Copy(unmanagedPswd, psbytes, 0, psbytes.Length);
Marshal.ZeroFreeGlobalAllocAnsi(unmanagedPswd);
try
{
Rfc2898DeriveBytes kd = new Rfc2898DeriveBytes(psbytes, salt, iterations);
TripleDES decAlg = TripleDES.Create();
decAlg.Key = kd.GetBytes(24);
decAlg.IV = IV;
MemoryStream memstr = new MemoryStream();
decrypt = new CryptoStream(memstr, decAlg.CreateDecryptor(), CryptoStreamMode.Write);
decrypt.Write(edata, 0, edata.Length);
decrypt.Flush();
decrypt.Close(); // this is REQUIRED.
byte[] cleartext = memstr.ToArray();
return cleartext;
}
catch (Exception e)
{
Console.WriteLine("Problem decrypting: {0}", e.Message);
return null;
}
}
public static RSACryptoServiceProvider DecodePrivateKeyInfo(byte[] pkcs8)
{
// encoded OID sequence for PKCS #1 rsaEncryption szOID_RSA_RSA = "1.2.840.113549.1.1.1"
// this byte[] includes the sequence byte and terminal encoded null
byte[] SeqOID = { 0x30, 0x0D, 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01, 0x05, 0x00 };
byte[] seq = new byte[15];
// --------- Set up stream to read the asn.1 encoded SubjectPublicKeyInfo blob ------
MemoryStream mem = new MemoryStream(pkcs8);
int lenstream = (int)mem.Length;
BinaryReader binr = new BinaryReader(mem); //wrap Memory Stream with BinaryReader for easy reading
byte bt = 0;
ushort twobytes = 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;
bt = binr.ReadByte();
if (bt != 0x02)
return null;
twobytes = binr.ReadUInt16();
if (twobytes != 0x0001)
return null;
seq = binr.ReadBytes(15); //read the Sequence OID
if (!CompareBytearrays(seq, SeqOID)) //make sure Sequence for OID is correct
return null;
bt = binr.ReadByte();
if (bt != 0x04) //expect an Octet string
return null;
bt = binr.ReadByte(); //read next byte, or next 2 bytes is 0x81 or 0x82; otherwise bt is the byte count
if (bt == 0x81)
binr.ReadByte();
else
if (bt == 0x82)
binr.ReadUInt16();
//------ at this stage, the remaining sequence should be the RSA private key
byte[] rsaprivkey = binr.ReadBytes((int)(lenstream - mem.Position));
RSACryptoServiceProvider rsacsp = DecodeRSAPrivateKey(rsaprivkey);
return rsacsp;
}
catch (Exception)
{
return null;
}
finally { binr.Close(); }
}
public 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);
Console.WriteLine("showing components ..");
// ------- create RSACryptoServiceProvider instance and initialize with public key -----
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)
{
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;
}
}
}
这是一个示例：
//using code
public void Sample()
{
OpenSSL.opensslkey libssl = new OpenSSL.opensslkey();
string SignedString = libssl.SignString(@"c:\test\aaaa121213123123aaa_t.key",
"0123456789", "||3.2|test|cadena|original|");
string Certificate = "";
string CertificateNumber = "";
libssl.CertificateData(@"c:\test\aaaa121213123123aaa_t.cer", out Certificate, out CertificateNumber);
【讨论】：