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
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
|
/*
ConnectBot: simple, powerful, open-source SSH client for Android
Copyright (C) 2007-2008 Kenny Root, Jeffrey Sharkey
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.connectbot.util;
import java.util.Vector;
import org.connectbot.R;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Typeface;
import android.graphics.Paint.FontMetrics;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
public class EntropyView extends View {
private static final int SHA1_MAX_BYTES = 20;
private static final int MILLIS_BETWEEN_INPUTS = 50;
private Paint mPaint;
private FontMetrics mFontMetrics;
private boolean mFlipFlop;
private long mLastTime;
private Vector<OnEntropyGatheredListener> listeners;
private byte[] mEntropy;
private int mEntropyByteIndex;
private int mEntropyBitIndex;
private int splitText = 0;
private float lastX = 0.0f, lastY = 0.0f;
public EntropyView(Context context) {
super(context);
setUpEntropy();
}
public EntropyView(Context context, AttributeSet attrs) {
super(context, attrs);
setUpEntropy();
}
private void setUpEntropy() {
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setTypeface(Typeface.DEFAULT);
mPaint.setTextAlign(Paint.Align.CENTER);
mPaint.setTextSize(16);
mPaint.setColor(Color.WHITE);
mFontMetrics = mPaint.getFontMetrics();
mEntropy = new byte[SHA1_MAX_BYTES];
mEntropyByteIndex = 0;
mEntropyBitIndex = 0;
listeners = new Vector<OnEntropyGatheredListener>();
}
public void addOnEntropyGatheredListener(OnEntropyGatheredListener listener) {
listeners.add(listener);
}
public void removeOnEntropyGatheredListener(OnEntropyGatheredListener listener) {
listeners.remove(listener);
}
@Override
public void onDraw(Canvas c) {
String prompt = String.format(getResources().getString(R.string.pubkey_touch_prompt),
(int)(100.0 * (mEntropyByteIndex / 20.0)) + (int)(5.0 * (mEntropyBitIndex / 8.0)));
if (splitText > 0 ||
mPaint.measureText(prompt) > (getWidth() * 0.8)) {
if (splitText == 0)
splitText = prompt.indexOf(" ", prompt.length() / 2);
c.drawText(prompt.substring(0, splitText),
getWidth() / 2.0f,
getHeight() / 2.0f + (mPaint.ascent() + mPaint.descent()),
mPaint);
c.drawText(prompt.substring(splitText),
getWidth() / 2.0f,
getHeight() / 2.0f - (mPaint.ascent() + mPaint.descent()),
mPaint);
} else {
c.drawText(prompt,
getWidth() / 2.0f,
getHeight() / 2.0f - (mFontMetrics.ascent + mFontMetrics.descent) / 2,
mPaint);
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
if (mEntropyByteIndex >= SHA1_MAX_BYTES
|| lastX == event.getX()
|| lastY == event.getY())
return true;
// Only get entropy every 200 milliseconds to ensure the user has moved around.
long now = System.currentTimeMillis();
if ((now - mLastTime) < MILLIS_BETWEEN_INPUTS)
return true;
else
mLastTime = now;
byte input;
lastX = event.getX();
lastY = event.getY();
// Get the lowest 4 bits of each X, Y input and concat to the entropy-gathering
// string.
if (mFlipFlop)
input = (byte)((((int)lastX & 0x0F) << 4) | ((int)lastY & 0x0F));
else
input = (byte)((((int)lastY & 0x0F) << 4) | ((int)lastX & 0x0F));
mFlipFlop = !mFlipFlop;
for (int i = 0; i < 4 && mEntropyByteIndex < SHA1_MAX_BYTES; i++) {
if ((input & 0x3) == 0x1) {
mEntropy[mEntropyByteIndex] <<= 1;
mEntropy[mEntropyByteIndex] |= 1;
mEntropyBitIndex++;
input >>= 2;
} else if ((input & 0x3) == 0x2) {
mEntropy[mEntropyByteIndex] <<= 1;
mEntropyBitIndex++;
input >>= 2;
}
if (mEntropyBitIndex >= 8) {
mEntropyBitIndex = 0;
mEntropyByteIndex++;
}
}
// SHA1PRNG only keeps 160 bits of entropy.
if (mEntropyByteIndex >= SHA1_MAX_BYTES) {
for (OnEntropyGatheredListener listener: listeners) {
listener.onEntropyGathered(mEntropy);
}
}
invalidate();
return true;
}
}
|
