--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/com/trilead/ssh2/crypto/KeyMaterial.java	Thu May 22 10:41:19 2014 -0700
@@ -0,0 +1,71 @@
+
+package com.trilead.ssh2.crypto;
+
+
+import java.math.BigInteger;
+
+import com.trilead.ssh2.crypto.digest.HashForSSH2Types;
+
+/**
+ * Establishes key material for iv/key/mac (both directions).
+ *
+ * @author Christian Plattner, plattner@trilead.com
+ * @version $Id: KeyMaterial.java,v 1.1 2007/10/15 12:49:56 cplattne Exp $
+ */
+public class KeyMaterial {
+    public byte[] initial_iv_client_to_server;
+    public byte[] initial_iv_server_to_client;
+    public byte[] enc_key_client_to_server;
+    public byte[] enc_key_server_to_client;
+    public byte[] integrity_key_client_to_server;
+    public byte[] integrity_key_server_to_client;
+
+    private static byte[] calculateKey(HashForSSH2Types sh, BigInteger K, byte[] H, byte type, byte[] SessionID,
+                                       int keyLength) {
+        byte[] res = new byte[keyLength];
+        int dglen = sh.getDigestLength();
+        int numRounds = (keyLength + dglen - 1) / dglen;
+        byte[][] tmp = new byte[numRounds][];
+        sh.reset();
+        sh.updateBigInt(K);
+        sh.updateBytes(H);
+        sh.updateByte(type);
+        sh.updateBytes(SessionID);
+        tmp[0] = sh.getDigest();
+        int off = 0;
+        int produced = Math.min(dglen, keyLength);
+        System.arraycopy(tmp[0], 0, res, off, produced);
+        keyLength -= produced;
+        off += produced;
+
+        for (int i = 1; i < numRounds; i++) {
+            sh.updateBigInt(K);
+            sh.updateBytes(H);
+
+            for (int j = 0; j < i; j++)
+                sh.updateBytes(tmp[j]);
+
+            tmp[i] = sh.getDigest();
+            produced = Math.min(dglen, keyLength);
+            System.arraycopy(tmp[i], 0, res, off, produced);
+            keyLength -= produced;
+            off += produced;
+        }
+
+        return res;
+    }
+
+    public static KeyMaterial create(String hashAlgo, byte[] H, BigInteger K, byte[] SessionID, int keyLengthCS,
+                                     int blockSizeCS, int macLengthCS, int keyLengthSC, int blockSizeSC, int macLengthSC)
+    throws IllegalArgumentException {
+        KeyMaterial km = new KeyMaterial();
+        HashForSSH2Types sh = new HashForSSH2Types(hashAlgo);
+        km.initial_iv_client_to_server = calculateKey(sh, K, H, (byte) 'A', SessionID, blockSizeCS);
+        km.initial_iv_server_to_client = calculateKey(sh, K, H, (byte) 'B', SessionID, blockSizeSC);
+        km.enc_key_client_to_server = calculateKey(sh, K, H, (byte) 'C', SessionID, keyLengthCS);
+        km.enc_key_server_to_client = calculateKey(sh, K, H, (byte) 'D', SessionID, keyLengthSC);
+        km.integrity_key_client_to_server = calculateKey(sh, K, H, (byte) 'E', SessionID, macLengthCS);
+        km.integrity_key_server_to_client = calculateKey(sh, K, H, (byte) 'F', SessionID, macLengthSC);
+        return km;
+    }
+}