从 RSACryptoServiceProvider 解码密钥

Question

我正在尝试使用 .ExportRSAPrivateKey() 从 RSACryptoServiceProvider 对象中提取私钥。根据 MSDN, it exports a "byte array containing the PKCS#1 RSAPrivateKey representation of this key", which representation is defined in Appendix A of RFC8017。因此，基于此，我假设它应该是 ASN1 编码的，并尝试使用 AsnReader class:

using (var rsa = new RSACryptoServiceProvider(1024))
{
    var priv = rsa.ExportRSAPrivateKey();
    var asnr = new AsnReader(priv, AsnEncodingRules.DER);
    var N = asnr.ReadInteger();
}

但是，此代码在 .ReadInteger() 上失败，例外情况是："The provided data is tagged with 'Universal' class value '16', but it should have been 'Universal' class value '2'."

我做错了什么？

Answer 1

这是因为 RSAPublicKey 是一个 SEQUENCE ...

所以你必须读取一个序列，然后，整数...

我猜你使用的是 Microsoft AsnReader class

因此，代码可能类似于：

var publicKey = asnr.ReadSequence()
var N = publickKey.ReadInteger()

从 RSACryptoServiceProvider 解码密钥

Decoding the keys from RSACryptoServiceProvider

.net

cryptography

rsa

.net-5

asn.1