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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 CmsAlgorithmProtection GetInstance(object obj)
{
if (obj == null)
return null;
if (obj is CmsAlgorithmProtection cmsAlgorithmProtection)
return cmsAlgorithmProtection;
return new CmsAlgorithmProtection(Asn1Sequence.GetInstance(obj));
}
public static CmsAlgorithmProtection GetInstance(Asn1TaggedObject taggedObject, bool declaredExplicit)
{
return new CmsAlgorithmProtection(Asn1Sequence.GetInstance(taggedObject, declaredExplicit));
}
public static readonly int Signature = 1;
public static readonly int Mac = 2;
private readonly AlgorithmIdentifier m_digestAlgorithm;
private readonly AlgorithmIdentifier m_signatureAlgorithm;
private readonly AlgorithmIdentifier m_macAlgorithm;
public CmsAlgorithmProtection(AlgorithmIdentifier digestAlgorithm, int type, AlgorithmIdentifier algorithmIdentifier)
{
m_digestAlgorithm = digestAlgorithm ?? throw new ArgumentNullException(nameof(digestAlgorithm));
if (algorithmIdentifier == null)
throw new ArgumentNullException(nameof(algorithmIdentifier));
if (type == 1)
{
m_signatureAlgorithm = algorithmIdentifier;
m_macAlgorithm = null;
}
else if (type == 2)
{
m_signatureAlgorithm = null;
m_macAlgorithm = algorithmIdentifier;
}
else
{
throw new ArgumentException("Unknown type: " + type);
}
}
private CmsAlgorithmProtection(Asn1Sequence seq)
{
int count = seq.Count, pos = 0;
// RFC 6211 2. Exactly one of signatureAlgorithm or macAlgorithm SHALL be present.
if (count != 2)
throw new ArgumentException("Bad sequence size: " + count, nameof(seq));
m_digestAlgorithm = AlgorithmIdentifier.GetInstance(seq[pos++]);
m_signatureAlgorithm = Asn1Utilities.ReadOptionalContextTagged(seq, ref pos, 1, false, AlgorithmIdentifier.GetInstance);
m_macAlgorithm = Asn1Utilities.ReadOptionalContextTagged(seq, ref pos, 2, false, AlgorithmIdentifier.GetInstance);
if (pos != count)
throw new ArgumentException("Unexpected elements in sequence", nameof(seq));
}
public AlgorithmIdentifier DigestAlgorithm => m_digestAlgorithm;
public AlgorithmIdentifier MacAlgorithm => m_macAlgorithm;
public AlgorithmIdentifier SignatureAlgorithm => m_signatureAlgorithm;
public override Asn1Object ToAsn1Object()
{
Asn1EncodableVector v = new Asn1EncodableVector(3);
v.Add(m_digestAlgorithm);
v.AddOptionalTagged(false, 1, m_signatureAlgorithm);
v.AddOptionalTagged(false, 2, m_macAlgorithm);
return new DerSequence(v);
}
}
}
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