CMSAuthEnvelopedData.cs
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using System;
using System.Collections;
using System.IO;
using Org.BouncyCastle.Asn1;
using Org.BouncyCastle.Asn1.Cms;
using Org.BouncyCastle.Asn1.X509;
using Org.BouncyCastle.Crypto.Parameters;
namespace Org.BouncyCastle.Cms
{
/**
* containing class for an CMS AuthEnveloped Data object
*/
internal class CmsAuthEnvelopedData
{
internal RecipientInformationStore recipientInfoStore;
internal ContentInfo contentInfo;
private OriginatorInfo originator;
private AlgorithmIdentifier authEncAlg;
private Asn1Set authAttrs;
private byte[] mac;
private Asn1Set unauthAttrs;
public CmsAuthEnvelopedData(
byte[] authEnvData)
: this(CmsUtilities.ReadContentInfo(authEnvData))
{
}
public CmsAuthEnvelopedData(
Stream authEnvData)
: this(CmsUtilities.ReadContentInfo(authEnvData))
{
}
public CmsAuthEnvelopedData(
ContentInfo contentInfo)
{
this.contentInfo = contentInfo;
AuthEnvelopedData authEnvData = AuthEnvelopedData.GetInstance(contentInfo.Content);
this.originator = authEnvData.OriginatorInfo;
//
// read the recipients
//
Asn1Set recipientInfos = authEnvData.RecipientInfos;
//
// read the auth-encrypted content info
//
EncryptedContentInfo authEncInfo = authEnvData.AuthEncryptedContentInfo;
this.authEncAlg = authEncInfo.ContentEncryptionAlgorithm;
CmsSecureReadable secureReadable = new AuthEnvelopedSecureReadable(this);
//
// build the RecipientInformationStore
//
this.recipientInfoStore = CmsEnvelopedHelper.BuildRecipientInformationStore(
recipientInfos, secureReadable);
// FIXME These need to be passed to the AEAD cipher as AAD (Additional Authenticated Data)
this.authAttrs = authEnvData.AuthAttrs;
this.mac = authEnvData.Mac.GetOctets();
this.unauthAttrs = authEnvData.UnauthAttrs;
}
private class AuthEnvelopedSecureReadable : CmsSecureReadable
{
private readonly CmsAuthEnvelopedData parent;
internal AuthEnvelopedSecureReadable(CmsAuthEnvelopedData parent)
{
this.parent = parent;
}
public AlgorithmIdentifier Algorithm
{
get { return parent.authEncAlg; }
}
public object CryptoObject
{
get { return null; }
}
public CmsReadable GetReadable(KeyParameter key)
{
// TODO Create AEAD cipher instance to decrypt and calculate tag ( MAC)
throw new CmsException("AuthEnveloped data decryption not yet implemented");
// RFC 5084 ASN.1 Module
// -- Parameters for AlgorithmIdentifier
//
// CCMParameters ::= SEQUENCE {
// aes-nonce OCTET STRING (SIZE(7..13)),
// aes-ICVlen AES-CCM-ICVlen DEFAULT 12 }
//
// AES-CCM-ICVlen ::= INTEGER (4 | 6 | 8 | 10 | 12 | 14 | 16)
//
// GCMParameters ::= SEQUENCE {
// aes-nonce OCTET STRING, -- recommended size is 12 octets
// aes-ICVlen AES-GCM-ICVlen DEFAULT 12 }
//
// AES-GCM-ICVlen ::= INTEGER (12 | 13 | 14 | 15 | 16)
}
}
}
}