1 files changed, 91 insertions, 0 deletions
diff --git a/sshlib/src/main/java/com/trilead/ssh2/crypto/KeyMaterial.java b/sshlib/src/main/java/com/trilead/ssh2/crypto/KeyMaterial.java
new file mode 100644
index 0000000..1dbd6c7
--- /dev/null
+++ b/sshlib/src/main/java/com/trilead/ssh2/crypto/KeyMaterial.java
@@ -0,0 +1,91 @@
+
+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;
+	}
+}