How would I reverse engineer a cryptographic algorithm?

Question

I wrote an application that encrypts text in this way:

1. Get the input text

2. Reverse the text

3. Convert to hexadecimal

4. <

Answer 1

That is kind of impossible, you'd fail at the XOR decryption if you don't have any knowledge about what key was used.

In a general case, it is even more impossible (if that is possible :)) to gauge what an encrypted string might mean.