1 files changed, 86 insertions, 0 deletions
diff --git a/src/org/theb/ssh/TouchEntropy.java b/src/org/theb/ssh/TouchEntropy.java
new file mode 100644
index 0000000..33ad499
--- /dev/null
+++ b/src/org/theb/ssh/TouchEntropy.java
@@ -0,0 +1,86 @@
+package org.theb.ssh;
+
+import android.app.Activity;
+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.os.Bundle;
+import android.util.Log;
+import android.view.MotionEvent;
+import android.view.View;
+
+public class TouchEntropy extends Activity {
+	protected String  mEntropy;
+	
+    @Override
+    protected void onCreate(Bundle icicle) {
+        super.onCreate(icicle);
+        
+        mEntropy = new String();
+        setContentView(new TouchView(this));
+    }
+    
+    class TouchView extends View {
+    	Paint mPaint;
+    	FontMetrics mFontMetrics;
+    	
+    	private boolean mFlipFlop = false;
+    	private long mLastTime = 0;
+    	    	
+        public TouchView(Context c) {
+            super(c);
+        	
+        	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();
+        }
+        
+        @Override
+        public void onDraw(Canvas c) {
+        	String prompt = getResources().getString(R.string.prompt_touch);
+        	c.drawText(prompt + " " + (int)(100.0 * (mEntropy.length() / 20.0)) + "% done",
+        			getWidth() / 2,
+        			getHeight() / 2 - (mFontMetrics.ascent + mFontMetrics.descent) / 2,
+        			mPaint);
+        }
+        
+        @Override
+        public boolean onMotionEvent(MotionEvent event) {
+        	// Only get entropy every 200 milliseconds to ensure the user has moved around.
+        	long now = System.currentTimeMillis();
+        	if ((now - mLastTime) < 200)
+        		return true;
+        	else
+        		mLastTime = now;
+        	
+        	Log.d("SSH", "Last time was " + mLastTime);
+
+
+        	// Get the lowest 4 bits of each X, Y input and concat to the entropy-gathering
+        	// string.
+        	if (mFlipFlop)
+        		mEntropy += (byte)(((int)event.getX() & 0xF0) | ((int)event.getY() & 0x0F));
+        	else
+        		mEntropy += (byte)(((int)event.getY() & 0xF0) | ((int)event.getX() & 0x0F));
+        	
+        	mFlipFlop = !mFlipFlop;
+                	
+        	// SHA1PRNG only keeps 20 bytes (160 bits) of entropy.
+        	if (mEntropy.length() > 20) {
+        		TouchEntropy.this.setResult(RESULT_OK, mEntropy);
+        		TouchEntropy.this.finish();
+        	}
+        	
+        	invalidate();
+        	
+            return true;
+        }
+    }
+}