CODEWITHSUNDEEP
javaencryptioncryptographybase64
Magundi
Magundi

Reputation: 21

Java PBEwithMD5andDES decryption issue

I have an encryption method that works well and passes me an encrypted String.

    KeySpec keySpec = new PBEKeySpec(encryptionPassword.toCharArray(), salt, iterations);

    SecretKey key = SecretKeyFactory.getInstance("PBEWithMD5AndDES").generateSecret(keySpec);
    AlgorithmParameterSpec paramSpec = new PBEParameterSpec(salt, iterations);


//encryption
    Cipher encoder = Cipher.getInstance(key.getAlgorithm());
    encoder.init(Cipher.ENCRYPT_MODE, key, paramSpec);

    String str_to_encrypt = "Hello";
    byte[] enc = encoder.doFinal(str_to_encrypt.getBytes("UTF8"));

    System.out.println("encrypted = " + DatatypeConverter.printBase64Binary(enc));


output: encrypted = vjXsSX0cBNc=

However I also wish to Decrypt this String I've recieved, I am having trouble with this however, especially the reverse of getBytes and printBase64Binary.

This is the first time I have attempted to decrypt, so I used a lot of Googling, I found that 'parseBase64Binary' could get bytes from a string, with 'new String(dec, "US-ASCII") then turning the bytes into a string...somewhere something went askew.

//decryption
   Cipher encoder = Cipher.getInstance(key.getAlgorithm());
   encoder.init(Cipher.DECRYPT_MODE, key, paramSpec);

   String str_to_decrypt = "vjXsSX0cBNc=";
   byte[] dec = DatatypeConverter.parseBase64Binary(str_to_decrypt);

   System.out.println("decrypted = " + new String(dec, "UTF8"));


output: decrypted = ?5?I}?

The only thing I can think of is that I haven't actually decrypted the string properly, as I have not used encoder.doFinal anywhere... somewhat stumped as to where to use it.

Upvotes: 1

Views: 3461

Answers (1)

Magundi
Magundi

Reputation: 21

EDIT: Answered own question for completeness, all sorted!

Played around a bit more, I was right in saying I hadn't properly decrypted the String as I hadn't used encoder.doFinal... trial and error led me to this:

 String str_to_decrypt = "vjXsSX0cBNc=";

 byte[] dec = encoder.doFinal(DatatypeConverter.parseBase64Binary(str_to_decrypt));

 System.out.println("decrypted = " + new String(dec, "UTF8"));


output: decrypted = Hello

Upvotes: 1

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