Help identify crypto

[The Old Pirate]

Hi all.

How do you identify the cipher based on the assembly code of the encryption algorithm? I tried to use tools such as IDAScope, signsrch etc but none of them have found any constants (the program is not obfuscated).

I think the cipher in question is a common one but I am unable to tell which one. From what I see the ciphertext is a 256-byte block. There is also a static array in the code of which first 256 bytes are taken (the key?). Then I see both blocks are copied in memory in reverse order and then the magic is done.

Is anyone able to recognize it based on this description?