/**
* @param key
* @param update_key
* @return
* @throws CryptoException
*/
public byte[] update(byte[] key, byte[] update_key) throws CryptoException {
byte[] shasig = new byte[20];
byte[] update = new byte[this.keylength]; // changed from 8 - rdesktop
// 1.2.0
byte[] thekey = new byte[key.length];
synchronized (digestLock) {
sha1.reset();
sha1.update(update_key, 0, keylength);
sha1.update(pad_54, 0, 40);
sha1.update(key, 0, keylength); // changed from 8 - rdesktop
// 1.2.0
shasig = sha1.digest();
sha1.reset();
md5.reset();
md5.update(update_key, 0, keylength); // changed from 8 - rdesktop
// 1.2.0
md5.update(pad_92, 0, 48);
md5.update(shasig, 0, 20);
thekey = md5.digest();
md5.reset();
System.arraycopy(thekey, 0, update, 0, this.keylength);
rc4_update.engineInitDecrypt(update);
// added
thekey = rc4_update.crypt(thekey, 0, this.keylength);
if (this.keylength == 8) {
this.make40bit(thekey);
}
}
return thekey;
}
/**
* Generate encryption keys of applicable size for connection
*
* @param rc4_key_size Size of keys to generate (1 if 40-bit encryption, otherwise 128-bit)
* @throws CryptoException
*/
public void generate_keys(int rc4_key_size) throws CryptoException {
byte[] session_key = new byte[48];
byte[] temp_hash = new byte[48];
byte[] input = new byte[48];
System.arraycopy(this.client_random, 0, input, 0, 24);
System.arraycopy(this.server_random, 0, input, 24, 24);
temp_hash = this.hash48(input, this.client_random, this.server_random, 65);
session_key = this.hash48(temp_hash, this.client_random, this.server_random, 88);
System.arraycopy(session_key, 0, this.sec_sign_key, 0, 16);
// changed from 8 - rdesktop 1.2.0
this.sec_decrypt_key = this.hash16(session_key, this.client_random, this.server_random, 16);
this.sec_encrypt_key = this.hash16(session_key, this.client_random, this.server_random, 32);
if (rc4_key_size == 1) {
logger.info("40 Bit Encryption enabled");
this.make40bit(this.sec_sign_key);
this.make40bit(this.sec_decrypt_key);
this.make40bit(this.sec_encrypt_key);
this.keylength = 8;
} else {
logger.info("128 Bit Encryption enabled");
this.keylength = 16;
}
System.arraycopy(
this.sec_decrypt_key,
0,
this.sec_decrypt_update_key,
0,
16); // changed from 8 - rdesktop 1.2.0
System.arraycopy(
this.sec_encrypt_key,
0,
this.sec_encrypt_update_key,
0,
16); // changed from 8 - rdesktop 1.2.0
byte[] key = new byte[this.keylength];
System.arraycopy(this.sec_encrypt_key, 0, key, 0, this.keylength);
rc4_enc.engineInitEncrypt(key);
System.arraycopy(this.sec_decrypt_key, 0, key, 0, this.keylength);
rc4_dec.engineInitDecrypt(key);
}