/* * Copyright (c) 2006-2011 Christian Plattner. All rights reserved. * Please refer to the LICENSE.txt for licensing details. */ package ch.ethz.ssh2.crypto.digest; /** * HMAC. * * @author Christian Plattner * @version 2.50, 03/15/10 */ public final class HMAC implements Digest { Digest md; byte[] k_xor_ipad; byte[] k_xor_opad; byte[] tmp; int size; public HMAC(Digest md, byte[] key, int size) { this.md = md; this.size = size; tmp = new byte[md.getDigestLength()]; int blocksize = 64; k_xor_ipad = new byte[blocksize]; k_xor_opad = new byte[blocksize]; if (key.length > blocksize) { md.reset(); md.update(key); md.digest(tmp); key = tmp; } System.arraycopy(key, 0, k_xor_ipad, 0, key.length); System.arraycopy(key, 0, k_xor_opad, 0, key.length); for (int i = 0; i < blocksize; i++) { k_xor_ipad[i] ^= 0x36; k_xor_opad[i] ^= 0x5C; } md.update(k_xor_ipad); } public int getDigestLength() { return size; } public void update(byte b) { md.update(b); } public void update(byte[] b) { md.update(b); } public void update(byte[] b, int off, int len) { md.update(b, off, len); } public void reset() { md.reset(); md.update(k_xor_ipad); } public void digest(byte[] out) { digest(out, 0); } public void digest(byte[] out, int off) { md.digest(tmp); md.update(k_xor_opad); md.update(tmp); md.digest(tmp); System.arraycopy(tmp, 0, out, off, size); md.update(k_xor_ipad); } }