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using System;
using Org.BouncyCastle.Asn1.X509;
namespace Org.BouncyCastle.Asn1.Cms
{
/**
* From RFC 6211
* <pre>
* CMSAlgorithmProtection ::= SEQUENCE {
* digestAlgorithm DigestAlgorithmIdentifier,
* signatureAlgorithm [1] SignatureAlgorithmIdentifier OPTIONAL,
* macAlgorithm [2] MessageAuthenticationCodeAlgorithm
* OPTIONAL
* }
* (WITH COMPONENTS { signatureAlgorithm PRESENT,
* macAlgorithm ABSENT } |
* WITH COMPONENTS { signatureAlgorithm ABSENT,
* macAlgorithm PRESENT })
* </pre>
*/
public class CmsAlgorithmProtection
: Asn1Encodable
{
public static readonly int Signature = 1;
public static readonly int Mac = 2;
private readonly AlgorithmIdentifier digestAlgorithm;
private readonly AlgorithmIdentifier signatureAlgorithm;
private readonly AlgorithmIdentifier macAlgorithm;
public CmsAlgorithmProtection(AlgorithmIdentifier digestAlgorithm, int type, AlgorithmIdentifier algorithmIdentifier)
{
if (digestAlgorithm == null || algorithmIdentifier == null)
throw new ArgumentException("AlgorithmIdentifiers cannot be null");
this.digestAlgorithm = digestAlgorithm;
if (type == 1)
{
this.signatureAlgorithm = algorithmIdentifier;
this.macAlgorithm = null;
}
else if (type == 2)
{
this.signatureAlgorithm = null;
this.macAlgorithm = algorithmIdentifier;
}
else
{
throw new ArgumentException("Unknown type: " + type);
}
}
private CmsAlgorithmProtection(Asn1Sequence sequence)
{
if (sequence.Count != 2)
throw new ArgumentException("Sequence wrong size: One of signatureAlgorithm or macAlgorithm must be present");
this.digestAlgorithm = AlgorithmIdentifier.GetInstance(sequence[0]);
Asn1TaggedObject tagged = Asn1TaggedObject.GetInstance(sequence[1]);
if (tagged.TagNo == 1)
{
this.signatureAlgorithm = AlgorithmIdentifier.GetInstance(tagged, false);
this.macAlgorithm = null;
}
else if (tagged.TagNo == 2)
{
this.signatureAlgorithm = null;
this.macAlgorithm = AlgorithmIdentifier.GetInstance(tagged, false);
}
else
{
throw new ArgumentException("Unknown tag found: " + tagged.TagNo);
}
}
public static CmsAlgorithmProtection GetInstance(object obj)
{
if (obj == null)
return null;
if (obj is CmsAlgorithmProtection cmsAlgorithmProtection)
return cmsAlgorithmProtection;
return new CmsAlgorithmProtection(Asn1Sequence.GetInstance(obj));
}
public AlgorithmIdentifier DigestAlgorithm => digestAlgorithm;
public AlgorithmIdentifier MacAlgorithm => macAlgorithm;
public AlgorithmIdentifier SignatureAlgorithm => signatureAlgorithm;
public override Asn1Object ToAsn1Object()
{
Asn1EncodableVector v = new Asn1EncodableVector(3);
v.Add(digestAlgorithm);
v.AddOptionalTagged(false, 1, signatureAlgorithm);
v.AddOptionalTagged(false, 2, macAlgorithm);
return new DerSequence(v);
}
}
}
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