diff options
Diffstat (limited to 'app/src/main/java/org/connectbot/util/EntropyView.java')
| -rw-r--r-- | app/src/main/java/org/connectbot/util/EntropyView.java | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/app/src/main/java/org/connectbot/util/EntropyView.java b/app/src/main/java/org/connectbot/util/EntropyView.java new file mode 100644 index 0000000..c988673 --- /dev/null +++ b/app/src/main/java/org/connectbot/util/EntropyView.java @@ -0,0 +1,169 @@ +/* + * ConnectBot: simple, powerful, open-source SSH client for Android + * Copyright 2007 Kenny Root, Jeffrey Sharkey + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +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; + } +} |