blob: f629caba6a9643b0e3412c6eeaf5efe63ce2d19f (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
|
using System;
using System.IO;
using Org.BouncyCastle.Asn1;
using Org.BouncyCastle.Asn1.Cms;
using Org.BouncyCastle.Asn1.X509;
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Security;
namespace Org.BouncyCastle.Cms
{
/**
* the RecipientInfo class for a recipient who has been sent a message
* encrypted using a password.
*/
public class PasswordRecipientInformation
: RecipientInformation
{
private readonly PasswordRecipientInfo info;
internal PasswordRecipientInformation(
PasswordRecipientInfo info,
CmsSecureReadable secureReadable)
: base(info.KeyEncryptionAlgorithm, secureReadable)
{
this.info = info;
this.rid = new RecipientID();
}
/**
* return the object identifier for the key derivation algorithm, or null
* if there is none present.
*
* @return OID for key derivation algorithm, if present.
*/
public virtual AlgorithmIdentifier KeyDerivationAlgorithm
{
get { return info.KeyDerivationAlgorithm; }
}
/**
* decrypt the content and return an input stream.
*/
public override CmsTypedStream GetContentStream(
ICipherParameters key)
{
try
{
AlgorithmIdentifier kekAlg = AlgorithmIdentifier.GetInstance(info.KeyEncryptionAlgorithm);
Asn1Sequence kekAlgParams = (Asn1Sequence)kekAlg.Parameters;
byte[] encryptedKey = info.EncryptedKey.GetOctets();
string kekAlgName = DerObjectIdentifier.GetInstance(kekAlgParams[0]).Id;
string cName = CmsEnvelopedHelper.Instance.GetRfc3211WrapperName(kekAlgName);
IWrapper keyWrapper = WrapperUtilities.GetWrapper(cName);
byte[] iv = Asn1OctetString.GetInstance(kekAlgParams[1]).GetOctets();
ICipherParameters parameters = ((CmsPbeKey)key).GetEncoded(kekAlgName);
parameters = new ParametersWithIV(parameters, iv);
keyWrapper.Init(false, parameters);
KeyParameter sKey = ParameterUtilities.CreateKeyParameter(
GetContentAlgorithmName(), keyWrapper.Unwrap(encryptedKey, 0, encryptedKey.Length));
return GetContentFromSessionKey(sKey);
}
catch (SecurityUtilityException e)
{
throw new CmsException("couldn't create cipher.", e);
}
catch (InvalidKeyException e)
{
throw new CmsException("key invalid in message.", e);
}
}
}
}
|
