/// <summary>
/// Create the digest signing context.
/// </summary>
/// <remarks>
/// Creates a new digest signing context that uses the specified algorithm.
/// </remarks>
/// <param name="algorithm">The DKIM signature algorithm.</param>
/// <param name="key">The public key.</param>
/// <returns>The digest signer.</returns>
internal virtual ISigner CreateVerifyContext(DkimSignatureAlgorithm algorithm, AsymmetricKeyParameter key)
{
#if ENABLE_NATIVE_DKIM
return(new SystemSecuritySigner(algorithm, key.AsAsymmetricAlgorithm()));
#else
ISigner signer;
switch (algorithm)
{
case DkimSignatureAlgorithm.RsaSha1:
signer = new RsaDigestSigner(new Sha1Digest());
break;
case DkimSignatureAlgorithm.RsaSha256:
signer = new RsaDigestSigner(new Sha256Digest());
break;
case DkimSignatureAlgorithm.Ed25519Sha256:
signer = new Ed25519DigestSigner(new Sha256Digest());
break;
default:
throw new NotSupportedException(string.Format("{0} is not supported.", algorithm));
}
signer.Init(key.IsPrivate, key);
return(signer);
#endif
}