How do I encrypt/decrypt a string with another string as a password?

Question

I\'m making a simple program that takes text entered in a text box, and takes a password that\'s in another text box, then does some sort of simple encryption on it and saves it

Answer 1

What you really need is Symmetric cryptography, i.e., the algorithm uses same key to encrypt and decrypt the data. There are many algorithms available which support symmetric cryptography like DES, AES.

Have a look at this example: http://www.java2s.com/Code/Java/Security/EncryptionanddecryptionwithAESECBPKCS7Padding.htm

In the above example, replace

byte[] keyBytes = new byte[] { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
    0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17 };

with

byte[] keyBytes = yourPassword.getBytes();

It uses the bouncycastle library, which is arguably the best cryptography libraries available.