How to get password as string back from encrypted password byte array.

Question

Hi All,
I am storing encrypted password and enc key in the database.(Code included encryptPassword method for encryption and validatePassword method for validating of password). Problem is that for some reason i need to show user's password to the user as a string as he/she entered. But i am not able to convert the encrypted password from D/B to original String.
Tell me if any body know how to get the string password back from the encrypted password byte array after seeing my existing encryption code.
//********* Code
private Vector encryptPassword(byte[] arrPwd)
try
// parameter arrPwd is the password as entered by the user and to be encrypted.
byte[] encPwd = null;
byte[] key = null;
/* Generate a key pair */
KeyPairGenerator keyGen = KeyPairGenerator.getInstance("DSA", "SUN");
SecureRandom random = SecureRandom.getInstance("SHA1PRNG", "SUN");
keyGen.initialize(1024, random);
KeyPair pair = keyGen.generateKeyPair();
PrivateKey priv = pair.getPrivate();
PublicKey pub = pair.getPublic();
/* Create a Signature object and initialize it with the private key */
Signature dsa = Signature.getInstance("SHA1withDSA", "SUN");
dsa.initSign(priv);
/* Update and sign the data */
dsa.update(arrPwd, 0, 12);
/* Now that all the data to be signed has been read in, generate a signature for it */
encPwd = dsa.sign();
/* Now realSig has the signed password*/
key = pub.getEncoded();
Vector vtrPwd = new Vector(2);
vtrPwd.add(encPwd);
vtrPwd.add(key);
return vtrPwd;
catch (Exception e)
private boolean validatePassword(byte[] arrPwd,byte[] encPwd,byte[] key) throws RemoteException
try
// arrPwd is the byte array of password entered by user.
// encPwd is the encrypted password retreived from D/B
// key is the array of key through which the password was encrypted and stored.
X509EncodedKeySpec KeySpec = new X509EncodedKeySpec(key);
KeyFactory keyFactory = KeyFactory.getInstance("DSA", "SUN");
PublicKey pubKey = keyFactory.generatePublic(KeySpec);
/* Encrypt the user-entered password using the key*/
Signature sig = Signature.getInstance("SHA1withDSA", "SUN");
sig.initVerify(pubKey);
/* Update and sign the password*/
sig.update(arrPwd, 0, 12);
return sig.verify(encPwd);
catch (Exception e)
Help upto any extent would be appreciated.
Thanx
Moti Singh

Answer 1

Hi All,
I am storing encrypted password and enc key in the
database.(Code included encryptPassword method for
encryption and validatePassword method for validating
of password). Problem is that for some reason i need
to show user's password to the user as a string as
he/she entered. But i am not able to convert the
encrypted password from D/B to original String.No, you are not encrypting the password in your code, you are merely signing it.
Tell me if any body know how to get the string
password back from the encrypted password byte array
after seeing my existing encryption code.It is impossible to retrieve the original text out of a signature.
You should read up on some encryption basics in order to understand the difference between signing and encrypting. Then you can find examples of how to encrypt something here: http://java.sun.com/j2se/1.4/docs/guide/security/jce/JCERefGuide.html.
Actually there is one class specifically for keeping keys secure, KeyStore http://java.sun.com/j2se/1.4/docs/api/java/security/KeyStore.html
- Daniel