c# – 从.NET Core中的PEM文件创建X509Certificate2

我想基于PEM文件创建X509Certificate2对象.问题是设置X509Certificate2的PrivateKey属性.我读了X509Certificate2.CreateFromCertFile() on .NET Core

然后用过

var rsa = new RSACryptoServiceProvider();

rsa.ImportCspBlob(pvk);

其中pvk是私钥的字节数组(从Get00ytesFromPEM读取,如此处所示how to get private key from PEM file?),设置私钥,但后来我得到了一个私钥

Internal.Cryptography.CryptoThrowHelper+WindowsCryptographicException with message Bad Version of provider.

如何根据PEM文件中的私钥正确设置X509Certificate2的PrivateKey？

如果我看看Creating the X509Certificate2,他们会使用

 RSACryptoServiceProvider prov = Crypto.DecodeRsaPrivateKey(keyBuffer);
 certificate.PrivateKey = prov;

这似乎是一种巧妙的方式来做到这一点,但这在.Net Core中不起作用……

解决方法:

如果您刚刚从私钥文件的Base64编码中提取字节,则您有PKCS#1,PKCS#8或加密的PKCS#8私钥blob(取决于它是否说“BEGIN RSA PRIVATE KEY”,“ BEGIN PRIVATE KEY“或”BEGIN ENCRYPTED PRIVATE KEY“). ImportCspBlob需要数据的自定义格式,这就是它抱怨的原因.

Digital signature in c# without using BouncyCastle解释了前进的方向.最简单/最公式化的方法是使用cert和key创建一个PFX,然后让X509Certificate2构造函数执行它的操作.

如果您直接加载密钥对象的路径,那么您将私钥与证书配对的方式是使用新的CopyWithPrivateKey扩展方法之一.这将返回X509Certificate2的新实例,该实例知道私钥.

PrivateKey setter是从.NET Core中“删除”的,因为它在Windows上有许多难以在Linux和macOS上复制的副作用,特别是如果您从X509Store的实例中检索证书.

此代码是过度严格和过度接受实际BER规则的组合,但这应该读取有效编码的PKCS#8文件,除非它们包含属性.

private static readonly byte[] s_derIntegerZero = { 0x02, 0x01, 0x00 };

private static readonly byte[] s_rsaAlgorithmId =
{
    0x30, 0x0D,
    0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01,
    0x05, 0x00,
};

private static int ReadLength(byte[] data, ref int offset)
{
    byte lengthOrLengthLength = data[offset++];

    if (lengthOrLengthLength < 0x80)
    {
        return lengthOrLengthLength;
    }

    int lengthLength = lengthOrLengthLength & 0x7F;
    int length = 0;

    for (int i = 0; i < lengthLength; i++)
    {
        if (length > ushort.MaxValue)
        {
            throw new InvalidOperationException("This seems way too big.");
        }

        length <<= 8;
        length |= data[offset++];
    }

    return length;
}

private static byte[] ReadUnsignedInteger(byte[] data, ref int offset, int targetSize = 0)
{
    if (data[offset++] != 0x02)
    {
        throw new InvalidOperationException("Invalid encoding");
    }

    int length = ReadLength(data, ref offset);

    // Encoding rules say 0 is encoded as the one byte value 0x00.
    // Since we expect unsigned, throw if the high bit is set.
    if (length < 1 || data[offset] >= 0x80)
    {
        throw new InvalidOperationException("Invalid encoding");
    }

    byte[] ret;

    if (length == 1)
    {
        ret = new byte[length];
        ret[0] = data[offset++];
        return ret;
    }

    if (data[offset] == 0)
    {
        offset++;
        length--;
    }

    if (targetSize != 0)
    {
        if (length > targetSize)
        {
            throw new InvalidOperationException("Bad key parameters");
        }

        ret = new byte[targetSize];
    }
    else
    {
        ret = new byte[length];
    }

    Buffer.BlockCopy(data, offset, ret, ret.Length - length, length);
    offset += length;
    return ret;
}

private static void EatFullPayloadTag(byte[] data, ref int offset, byte tagValue)
{
    if (data[offset++] != tagValue)
    {
        throw new InvalidOperationException("Invalid encoding");
    }

    int length = ReadLength(data, ref offset);

    if (data.Length - offset != length)
    {
        throw new InvalidOperationException("Data does not represent precisely one value");
    }
}

private static void EatMatch(byte[] data, ref int offset, byte[] toMatch)
{
    if (data.Length - offset > toMatch.Length)
    {
        if (data.Skip(offset).Take(toMatch.Length).SequenceEqual(toMatch))
        {
            offset += toMatch.Length;
            return;
        }
    }

    throw new InvalidOperationException("Bad data.");
}

private static RSA DecodeRSAPkcs8(byte[] pkcs8Bytes)
{
    int offset = 0;

    // PrivateKeyInfo SEQUENCE
    EatFullPayloadTag(pkcs8Bytes, ref offset, 0x30);
    // PKCS#8 PrivateKeyInfo.version == 0
    EatMatch(pkcs8Bytes, ref offset, s_derIntegerZero);
    // rsaEncryption AlgorithmIdentifier value
    EatMatch(pkcs8Bytes, ref offset, s_rsaAlgorithmId);
    // PrivateKeyInfo.privateKey OCTET STRING
    EatFullPayloadTag(pkcs8Bytes, ref offset, 0x04);
    // RSAPrivateKey SEQUENCE
    EatFullPayloadTag(pkcs8Bytes, ref offset, 0x30);
    // RSAPrivateKey.version == 0
    EatMatch(pkcs8Bytes, ref offset, s_derIntegerZero);

    RSAParameters rsaParameters = new RSAParameters();
    rsaParameters.Modulus = ReadUnsignedInteger(pkcs8Bytes, ref offset);
    rsaParameters.Exponent = ReadUnsignedInteger(pkcs8Bytes, ref offset);
    rsaParameters.D = ReadUnsignedInteger(pkcs8Bytes, ref offset, rsaParameters.Modulus.Length);
    int halfModulus = (rsaParameters.Modulus.Length + 1) / 2;
    rsaParameters.P = ReadUnsignedInteger(pkcs8Bytes, ref offset, halfModulus);
    rsaParameters.Q = ReadUnsignedInteger(pkcs8Bytes, ref offset, halfModulus);
    rsaParameters.DP = ReadUnsignedInteger(pkcs8Bytes, ref offset, halfModulus);
    rsaParameters.DQ = ReadUnsignedInteger(pkcs8Bytes, ref offset, halfModulus);
    rsaParameters.InverseQ = ReadUnsignedInteger(pkcs8Bytes, ref offset, halfModulus);

    if (offset != pkcs8Bytes.Length)
    {
        throw new InvalidOperationException("Something didn't add up");
    }

    RSA rsa = RSA.Create();
    rsa.ImportParameters(rsaParameters);
    return rsa;
}

标签：c,x509certificate,net-core,private-key,pem
来源： https://codeday.me/bug/20190701/1347088.html