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
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
|
package org.spongycastle.openpgp;
import java.io.EOFException;
import java.io.InputStream;
import org.spongycastle.bcpg.BCPGInputStream;
import org.spongycastle.bcpg.InputStreamPacket;
import org.spongycastle.bcpg.SymmetricEncIntegrityPacket;
import org.spongycastle.bcpg.SymmetricKeyEncSessionPacket;
import org.spongycastle.openpgp.operator.PBEDataDecryptorFactory;
import org.spongycastle.openpgp.operator.PGPDataDecryptor;
import org.spongycastle.util.io.TeeInputStream;
/**
* A password based encryption object.
*/
public class PGPPBEEncryptedData
extends PGPEncryptedData
{
SymmetricKeyEncSessionPacket keyData;
PGPPBEEncryptedData(
SymmetricKeyEncSessionPacket keyData,
InputStreamPacket encData)
{
super(encData);
this.keyData = keyData;
}
/**
* Return the raw input stream for the data stream.
*
* @return InputStream
*/
public InputStream getInputStream()
{
return encData.getInputStream();
}
/**
* Return the symmetric key algorithm required to decrypt the data protected by this object.
*
* @param dataDecryptorFactory decryptor factory to use to recover the session data.
* @return the integer encryption algorithm code.
* @throws PGPException if the session data cannot be recovered.
*/
public int getSymmetricAlgorithm(
PBEDataDecryptorFactory dataDecryptorFactory)
throws PGPException
{
byte[] key = dataDecryptorFactory.makeKeyFromPassPhrase(keyData.getEncAlgorithm(), keyData.getS2K());
byte[] sessionData = dataDecryptorFactory.recoverSessionData(keyData.getEncAlgorithm(), key, keyData.getSecKeyData());
return sessionData[0];
}
/**
* Open an input stream which will provide the decrypted data protected by this object.
*
* @param dataDecryptorFactory decryptor factory to use to recover the session data and provide the stream.
* @return the resulting input stream
* @throws PGPException if the session data cannot be recovered or the stream cannot be created.
*/
public InputStream getDataStream(
PBEDataDecryptorFactory dataDecryptorFactory)
throws PGPException
{
try
{
int keyAlgorithm = keyData.getEncAlgorithm();
byte[] key = dataDecryptorFactory.makeKeyFromPassPhrase(keyAlgorithm, keyData.getS2K());
boolean withIntegrityPacket = encData instanceof SymmetricEncIntegrityPacket;
byte[] sessionData = dataDecryptorFactory.recoverSessionData(keyData.getEncAlgorithm(), key, keyData.getSecKeyData());
byte[] sessionKey = new byte[sessionData.length - 1];
System.arraycopy(sessionData, 1, sessionKey, 0, sessionKey.length);
PGPDataDecryptor dataDecryptor = dataDecryptorFactory.createDataDecryptor(withIntegrityPacket, sessionData[0] & 0xff, sessionKey);
encStream = new BCPGInputStream(dataDecryptor.getInputStream(encData.getInputStream()));
if (withIntegrityPacket)
{
truncStream = new TruncatedStream(encStream);
integrityCalculator = dataDecryptor.getIntegrityCalculator();
encStream = new TeeInputStream(truncStream, integrityCalculator.getOutputStream());
}
byte[] iv = new byte[dataDecryptor.getBlockSize()];
for (int i = 0; i != iv.length; i++)
{
int ch = encStream.read();
if (ch < 0)
{
throw new EOFException("unexpected end of stream.");
}
iv[i] = (byte)ch;
}
int v1 = encStream.read();
int v2 = encStream.read();
if (v1 < 0 || v2 < 0)
{
throw new EOFException("unexpected end of stream.");
}
// Note: the oracle attack on "quick check" bytes is not deemed
// a security risk for PBE (see PGPPublicKeyEncryptedData)
boolean repeatCheckPassed = iv[iv.length - 2] == (byte) v1
&& iv[iv.length - 1] == (byte) v2;
// Note: some versions of PGP appear to produce 0 for the extra
// bytes rather than repeating the two previous bytes
boolean zeroesCheckPassed = v1 == 0 && v2 == 0;
if (!repeatCheckPassed && !zeroesCheckPassed)
{
throw new PGPDataValidationException("data check failed.");
}
return encStream;
}
catch (PGPException e)
{
throw e;
}
catch (Exception e)
{
throw new PGPException("Exception creating cipher", e);
}
}
}
|
