66 lines
1.8 KiB
C#
66 lines
1.8 KiB
C#
using System;
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using System.IO;
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using Org.BouncyCastle.Asn1.Cms;
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using Org.BouncyCastle.Asn1.X509;
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using Org.BouncyCastle.Crypto;
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using Org.BouncyCastle.Crypto.Parameters;
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using Org.BouncyCastle.Security;
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namespace Org.BouncyCastle.Cms
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{
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/**
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* the RecipientInfo class for a recipient who has been sent a message
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* encrypted using a secret key known to the other side.
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*/
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public class KekRecipientInformation
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: RecipientInformation
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{
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private KekRecipientInfo _info;
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// private AlgorithmIdentifier _encAlg;
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public KekRecipientInformation(
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KekRecipientInfo info,
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AlgorithmIdentifier encAlg,
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Stream data)
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: base(encAlg, AlgorithmIdentifier.GetInstance(info.KeyEncryptionAlgorithm), data)
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{
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this._info = info;
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this._encAlg = encAlg;
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this._rid = new RecipientID();
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KekIdentifier kekId = info.KekID;
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_rid.KeyIdentifier = kekId.KeyIdentifier.GetOctets();
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}
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/**
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* decrypt the content and return an input stream.
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*/
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public override CmsTypedStream GetContentStream(
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ICipherParameters key)
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{
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try
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{
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byte[] encryptedKey = _info.EncryptedKey.GetOctets();
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IWrapper keyWrapper = WrapperUtilities.GetWrapper(_keyEncAlg.ObjectID.Id);
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keyWrapper.Init(false, key);
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KeyParameter sKey = ParameterUtilities.CreateKeyParameter(
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_encAlg.ObjectID, keyWrapper.Unwrap(encryptedKey, 0, encryptedKey.Length));
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return GetContentFromSessionKey(sKey);
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}
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catch (SecurityUtilityException e)
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{
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throw new CmsException("couldn't create cipher.", e);
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}
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catch (InvalidKeyException e)
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{
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throw new CmsException("key invalid in message.", e);
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}
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}
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}
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}
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