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 cz.crcs.ectester.reader.ec;
import cz.crcs.ectester.applet.EC_Consts;
import cz.crcs.ectester.reader.Util;
import java.io.ByteArrayOutputStream;
import java.util.ArrayList;
import java.util.List;
/**
* A list of EC parameters, can contain a subset of the Fp/F2M, A, B, G, R, K, W, S parameters.
*
* The set of parameters is uniquely identified by a short bit string.
* The parameters can be exported to a byte array via <code>flatten()</code> or to a comma delimited
* string via <code>expand()</code>.
* @author Jan Jancar johny@neuromancer.sk
*/
public class EC_Params extends EC_Data {
private short params;
public EC_Params(short params) {
this.params = params;
this.count = numParams();
this.data = new byte[this.count][];
}
public EC_Params(short params, byte[][] data) {
this.params = params;
this.count = data.length;
this.data = data;
}
public EC_Params(String id, short params) {
this(params);
this.id = id;
}
public EC_Params(String id, short params, byte[][] data) {
this(params, data);
this.id = id;
}
public short getParams() {
return params;
}
public boolean hasParam(short param) {
return (params & param) != 0;
}
public int numParams() {
short paramMask = EC_Consts.PARAMETER_FP;
int num = 0;
while (paramMask <= EC_Consts.PARAMETER_S) {
if ((paramMask & params) != 0) {
if (paramMask == EC_Consts.PARAMETER_F2M) {
num += 3;
}
if (paramMask == EC_Consts.PARAMETER_W || paramMask == EC_Consts.PARAMETER_G) {
num += 1;
}
++num;
}
paramMask = (short) (paramMask << 1);
}
return num;
}
@Override
public byte[] flatten() {
return flatten(params);
}
public byte[] flatten(short params) {
ByteArrayOutputStream out = new ByteArrayOutputStream();
short paramMask = EC_Consts.PARAMETER_FP;
int i = 0;
while (paramMask <= EC_Consts.PARAMETER_S) {
short masked = (short) (this.params & params & paramMask);
short shallow = (short) (this.params & paramMask);
if (masked != 0) {
byte[] param = data[i];
if (masked == EC_Consts.PARAMETER_F2M) {
//add m, e_1, e_2, e_3
param = Util.concatenate(param, data[i + 1]);
if (!Util.allValue(data[i + 2], (byte) 0)) {
param = Util.concatenate(param, data[i + 2]);
}
if (!Util.allValue(data[i + 3], (byte) 0)) {
param = Util.concatenate(param, data[i + 3]);
}
if (!(param.length == 4 || param.length == 8))
throw new RuntimeException("PARAMETER_F2M length is not 8.(should be)");
}
if (masked == EC_Consts.PARAMETER_G || masked == EC_Consts.PARAMETER_W) {
//read another param (the y coord) and put into X962 format.
byte[] y = data[i + 1];
param = Util.concatenate(new byte[]{4}, param, y); //<- ugly but works!
}
if (param.length == 0)
throw new RuntimeException("Empty parameter read?");
//write length
byte[] length = new byte[2];
Util.setShort(length, 0, (short) param.length);
out.write(length, 0, 2);
//write data
out.write(param, 0, param.length);
}
if (shallow == EC_Consts.PARAMETER_F2M) {
i += 4;
} else if (shallow == EC_Consts.PARAMETER_G || shallow == EC_Consts.PARAMETER_W) {
i += 2;
} else if (shallow != 0) {
i++;
}
paramMask = (short) (paramMask << 1);
}
return (out.size() == 0) ? null : out.toByteArray();
}
@Override
public String[] expand() {
List<String> out = new ArrayList<>();
short paramMask = EC_Consts.PARAMETER_FP;
int index = 0;
while (paramMask <= EC_Consts.PARAMETER_S) {
short masked = (short) (params & paramMask);
if (masked != 0) {
byte[] param = data[index];
if (masked == EC_Consts.PARAMETER_F2M) {
for (int i = 0; i < 4; ++i) {
out.add(Util.bytesToHex(data[index + i], false));
}
index += 4;
} else if (masked == EC_Consts.PARAMETER_G || masked == EC_Consts.PARAMETER_W) {
out.add(Util.bytesToHex(param, false));
out.add(Util.bytesToHex(data[index + 1], false));
index += 2;
} else {
out.add(Util.bytesToHex(param, false));
index++;
}
}
paramMask = (short) (paramMask << 1);
}
return out.toArray(new String[out.size()]);
}
}
|
