blob: 5d4e74f964a7c6cfeb38f9da21d76fad5e18a01f (
plain)
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
142
143
144
145
146
147
148
149
150
151
|
package org.spongycastle.bcpg;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.math.BigInteger;
import org.spongycastle.asn1.ASN1ObjectIdentifier;
import org.spongycastle.asn1.ASN1Primitive;
import org.spongycastle.asn1.x9.ECNamedCurveTable;
import org.spongycastle.asn1.x9.X9ECParameters;
import org.spongycastle.crypto.ec.CustomNamedCurves;
import org.spongycastle.math.ec.ECAlgorithms;
import org.spongycastle.math.ec.ECPoint;
import org.spongycastle.util.BigIntegers;
/**
* base class for an EC Public Key.
*/
public abstract class ECPublicBCPGKey
extends BCPGObject
implements BCPGKey
{
ASN1ObjectIdentifier oid;
ECPoint point;
/**
* @param in the stream to read the packet from.
*/
protected ECPublicBCPGKey(
BCPGInputStream in)
throws IOException
{
this.oid = ASN1ObjectIdentifier.getInstance(ASN1Primitive.fromByteArray(readBytesOfEncodedLength(in)));
this.point = decodePoint(new MPInteger(in).getValue(), oid);
}
protected ECPublicBCPGKey(
ASN1ObjectIdentifier oid,
ECPoint point)
{
this.point = point.normalize();
this.oid = oid;
}
protected ECPublicBCPGKey(
ASN1ObjectIdentifier oid,
BigInteger encodedPoint)
throws IOException
{
this.point = decodePoint(encodedPoint, oid);
this.oid = oid;
}
/**
* return "PGP"
*
* @see org.spongycastle.bcpg.BCPGKey#getFormat()
*/
public String getFormat()
{
return "PGP";
}
/**
* return the standard PGP encoding of the key.
*
* @see org.spongycastle.bcpg.BCPGKey#getEncoded()
*/
public byte[] getEncoded()
{
try
{
ByteArrayOutputStream bOut = new ByteArrayOutputStream();
BCPGOutputStream pgpOut = new BCPGOutputStream(bOut);
pgpOut.writeObject(this);
return bOut.toByteArray();
}
catch (IOException e)
{
return null;
}
}
public void encode(
BCPGOutputStream out)
throws IOException
{
byte[] oid = this.oid.getEncoded();
out.write(oid, 1, oid.length - 1);
MPInteger point = new MPInteger(new BigInteger(1, this.point.getEncoded()));
out.writeObject(point);
}
/**
* @return point
*/
public ECPoint getPoint()
{
return point;
}
/**
* @return oid
*/
public ASN1ObjectIdentifier getCurveOID()
{
return oid;
}
protected static byte[] readBytesOfEncodedLength(
BCPGInputStream in)
throws IOException
{
int length = in.read();
if (length == 0 || length == 0xFF)
{
throw new IOException("future extensions not yet implemented.");
}
byte[] buffer = new byte[length + 2];
in.readFully(buffer, 2, buffer.length - 2);
buffer[0] = (byte)0x06;
buffer[1] = (byte)length;
return buffer;
}
private static ECPoint decodePoint(
BigInteger encodedPoint,
ASN1ObjectIdentifier oid)
throws IOException
{
X9ECParameters x9 = CustomNamedCurves.getByOID(oid);
if (x9 == null)
{
x9 = ECNamedCurveTable.getByOID(oid);
if (x9 == null)
{
throw new IOException(oid.getId() + " does not match any known curve.");
}
}
if (!ECAlgorithms.isFpCurve(x9.getCurve()))
{
throw new IOException("Only prime field curves are supported.");
}
return x9.getCurve().decodePoint(BigIntegers.asUnsignedByteArray(encodedPoint));
}
}
|
