/// <summary>
/// 从证书中提取公钥并转换为PEM格式
/// </summary>
/// <param name="input">证书</param>
/// <returns>PEM格式公钥</returns>
public static string ExtractPemPublicKeyFromCert(X509Certificate input)
{
using (var cert = new System.Security.Cryptography.X509Certificates.X509Certificate2(input.GetEncoded()))
{
byte[] algOid;
switch (cert.GetKeyAlgorithm())
{
case "1.2.840.113549.1.1.1":
algOid = new byte[] { 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01 };
break;
default:
throw new ArgumentOutOfRangeException("Need an OID lookup for " + cert.GetKeyAlgorithm());
}
var algParams = cert.GetKeyAlgorithmParameters();
var publicKey = WrapAsBitString(cert.GetPublicKey());
var algId = BuildSimpleDerSequence(algOid, algParams);
var spki = BuildSimpleDerSequence(algId, publicKey);
return(Convert.ToBase64String(spki));
}
}
/// <summary>
/// Gets the public key algorithm for the certificate.
/// </summary>
/// <remarks>
/// Gets the public key algorithm for the ceretificate.
/// </remarks>
/// <returns>The public key algorithm.</returns>
/// <param name="certificate">The certificate.</param>
/// <exception cref="System.ArgumentNullException">
/// <paramref name="certificate"/> is <c>null</c>.
/// </exception>
public static PublicKeyAlgorithm GetPublicKeyAlgorithm(this X509Certificate2 certificate)
{
if (certificate == null)
{
throw new ArgumentNullException(nameof(certificate));
}
var identifier = certificate.GetKeyAlgorithm();
var oid = new Oid(identifier);
switch (oid.FriendlyName)
{
case "DSA": return(PublicKeyAlgorithm.Dsa);
case "RSA": return(PublicKeyAlgorithm.RsaGeneral);
case "ECC": return(PublicKeyAlgorithm.EllipticCurve);
case "DH": return(PublicKeyAlgorithm.DiffieHellman);
default: return(PublicKeyAlgorithm.None);
}
}