--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/app/src/main/java/ch/ethz/ssh2/crypto/cipher/CipherInputStream.java	Thu Dec 03 11:23:55 2015 -0800
@@ -0,0 +1,146 @@
+/*
+ * Copyright (c) 2006-2011 Christian Plattner. All rights reserved.
+ * Please refer to the LICENSE.txt for licensing details.
+ */
+package ch.ethz.ssh2.crypto.cipher;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * CipherInputStream.
+ *
+ * @author Christian Plattner
+ * @version $Id: CipherInputStream.java 11 2011-05-27 14:14:06Z dkocher@sudo.ch $
+ */
+public class CipherInputStream {
+    BlockCipher currentCipher;
+    InputStream bi;
+    byte[] buffer;
+    byte[] enc;
+    int blockSize;
+    int pos;
+
+    /*
+     * We cannot use java.io.BufferedInputStream, since that is not available in
+     * J2ME. Everything could be improved alot here.
+     */
+
+    private static final int BUFF_SIZE = 8192;
+    byte[] input_buffer = new byte[BUFF_SIZE];
+    int input_buffer_pos = 0;
+    int input_buffer_size = 0;
+
+    public CipherInputStream(BlockCipher tc, InputStream bi) {
+        this.bi = bi;
+        changeCipher(tc);
+    }
+
+    private int fill_buffer() throws IOException {
+        input_buffer_pos = 0;
+        input_buffer_size = 0;
+        input_buffer_size = bi.read(input_buffer, 0, BUFF_SIZE);
+        return input_buffer_size;
+    }
+
+    private int internal_read(byte[] b, int off, int len) throws IOException {
+        if (input_buffer_size < 0) {
+            return -1;
+        }
+
+        if (input_buffer_pos >= input_buffer_size) {
+            if (fill_buffer() <= 0) {
+                return -1;
+            }
+        }
+
+        int avail = input_buffer_size - input_buffer_pos;
+        int thiscopy = (len > avail) ? avail : len;
+        System.arraycopy(input_buffer, input_buffer_pos, b, off, thiscopy);
+        input_buffer_pos += thiscopy;
+        return thiscopy;
+    }
+
+    public void changeCipher(BlockCipher bc) {
+        this.currentCipher = bc;
+        blockSize = bc.getBlockSize();
+        buffer = new byte[blockSize];
+        enc = new byte[blockSize];
+        pos = blockSize;
+    }
+
+    private void getBlock() throws IOException {
+        int n = 0;
+
+        while (n < blockSize) {
+            int len = internal_read(enc, n, blockSize - n);
+
+            if (len < 0) {
+                throw new IOException("Cannot read full block, EOF reached.");
+            }
+
+            n += len;
+        }
+
+        try {
+            currentCipher.transformBlock(enc, 0, buffer, 0);
+        }
+        catch (Exception e) {
+            throw new IOException("Error while decrypting block.");
+        }
+
+        pos = 0;
+    }
+
+    public int read(byte[] dst) throws IOException {
+        return read(dst, 0, dst.length);
+    }
+
+    public int read(byte[] dst, int off, int len) throws IOException {
+        int count = 0;
+
+        while (len > 0) {
+            if (pos >= blockSize) {
+                getBlock();
+            }
+
+            int avail = blockSize - pos;
+            int copy = Math.min(avail, len);
+            System.arraycopy(buffer, pos, dst, off, copy);
+            pos += copy;
+            off += copy;
+            len -= copy;
+            count += copy;
+        }
+
+        return count;
+    }
+
+    public int read() throws IOException {
+        if (pos >= blockSize) {
+            getBlock();
+        }
+
+        return buffer[pos++] & 0xff;
+    }
+
+    public int readPlain(byte[] b, int off, int len) throws IOException {
+        if (pos != blockSize) {
+            throw new IOException("Cannot read plain since crypto buffer is not aligned.");
+        }
+
+        int n = 0;
+
+        while (n < len) {
+            int cnt = internal_read(b, off + n, len - n);
+
+            if (cnt < 0) {
+                throw new IOException("Cannot fill buffer, EOF reached.");
+            }
+
+            n += cnt;
+        }
+
+        return n;
+    }
+}