Secret Password Encryption - Expert Oracle and Java Security - page 96

x.printStackTrace();
}
return rtrnString;
}
The first thing we do in the try block is to test whether the sessionSecretDESKey has already been
instantiated. If not, then we call two methods: decryptSessionSecretDESPassPhrase() (discussed in the
next section) and makeSessionSecretDESKey() . We discussed makeSessionSecretDESKey() earlier in this
chapter—it is the same method we called to build to the secret password key initially on the Oracle
database. We are calling it again on the client to build an identical key.
When we test whether we already have the sessionSecretDESKey , we also test the boolean
testAsClientAndServer . The testAsClientAndServer boolean is always false , unless we are testing the
OracleJavaSecure class from its main() method. In the main() , when we set this boolean to true , we can
replace a locally generated DES secret password key with one coming from Oracle database at different
stages of testing. We will examine the code of the main() method a bit later in this chapter.
The getDecryptData() method is overloaded with a version that assumes the secret password key
has been built and does the decryption. It takes a RAW and returns the clear text as a String . The first
getDecryptData() method (shown previously) calls this second getDecryptData() method, see Listing 6-
15.
Listing 6-15. Decrypt Data with Existing Secret Password, getDecryptData()
public static final String getDecryptData( RAW cryptData ) {
if( null == cryptData ) return null;
String rtrnString = "getDecryptData() B failed";
try {
cipherDES.init( Cipher.DECRYPT_MODE, sessionSecretDESKey, paramSpec );
rtrnString = new String( cipherDES.doFinal( cryptData.getBytes() ) );
} catch( Exception x ) {
//x.printStackTrace();
//rtrnString = x.toString();
}
return rtrnString;
}
This same, second getDecryptData() method is also called to decrypt data on the Oracle database
for encrypted data inserts and updates coming from the client. There on the Oracle database, we
presumably know that we already have our DES secret password key.
Decrypting the DES Passphrase using RSA Private Key
The decryptSessionSecretDESPassPhrase() method uses the client's RSA private key to decrypt all the
artifacts of the server DES secret password key. The code is presented in Listing 6-16.
Listing 6-16. Decrypt Secret Password Key Artifacts, decryptSessionSecretDESPassPhrase()
private static void decryptSessionSecretDESPassPhrase(
RAW cryptSecretDESPassPhrase, RAW cryptSecretDESAlgorithm,
RAW cryptSecretDESSalt, RAW cryptSecretDESIterationCount )
throws Exception
{
cipherRSA.init( Cipher.DECRYPT_MODE, locRSAPrivKey );