Xored Trainer

In cryptography, the simple XOR cipher is a type of additive cipher,^[1] an encryption algorithm that operates according to the principles:

A ${\displaystyle \oplus }$ 0 = A,

A ${\displaystyle \oplus }$ A = 0,

Feb 26, 2007  I think that Xored Trainer Launcher may only work with NTSC games and not PAL games. This is unconfirmed, so let me know if this is true or not. The other possible solution is that the Trainer I had didn't work properly and it affected all of the other trainers (which, after I deleted the trainer, all the rest worked fine).

(A ${\displaystyle \oplus }$ B) ${\displaystyle \oplus }$ C = A ${\displaystyle \oplus }$ (B ${\displaystyle \oplus }$ C),

(B ${\displaystyle \oplus }$ A) ${\displaystyle \oplus }$ A = B ${\displaystyle \oplus }$ 0 = B,

where ${\displaystyle \oplus }$ denotes the exclusive disjunction (XOR) operation. This operation is sometimes called modulus 2 addition (or subtraction, which is identical).^[2] With this logic, a string of text can be encrypted by applying the bitwise XOR operator to every character using a given key. To decrypt the output, merely reapplying the XOR function with the key will remove the cipher.

Example[edit]

For example, the string 'Wiki' (01010111 01101001 01101011 01101001 in 8-bit ASCII) can be encrypted with the repeating key 11110011 as follows:

And conversely, for decryption:

Use and security[edit]

The XOR operator is extremely common as a component in more complex ciphers. By itself, using a constant repeating key, a simple XOR cipher can trivially be broken using frequency analysis. If the content of any message can be guessed or otherwise known then the key can be revealed. Its primary merit is that it is simple to implement, and that the XOR operation is computationally inexpensive. A simple repeating XOR (i.e. using the same key for xor operation on the whole data) cipher is therefore sometimes used for hiding information in cases where no particular security is required. The XOR cipher is often used in computer malware to make reverse engineering more difficult.

If the key is random and is at least as long as the message, the XOR cipher is much more secure than when there is key repetition within a message.^[3] When the keystream is generated by a pseudo-random number generator, the result is a stream cipher. With a key that is truly random, the result is a one-time pad, which is unbreakable in theory.

In any of these ciphers, the XOR operator is vulnerable to a known-plaintext attack, since plaintext${\displaystyle \oplus }$ciphertext = key.It is also trivial to flip arbitrary bits in the decrypted plaintext by manipulating the ciphertext.This is called malleability.

Example implementation[edit]

Lion king legacy collection download. Example using the Python programming language.^[4]

See also[edit]

References[edit]

1. ^Tutte 1998, p. 3
2. ^Churchhouse 2002, p. 11
3. ^Churchhouse 2002, p. 68
4. ^This was inspired by Richter, Wolfgang (August 3, 2012), 'Unbreakable Cryptography in 5 Minutes', Crossroads: The ACM Magazine for Students, Association for Computing Machinery

Bibliography[edit]

• Churchhouse, Robert (2002), Codes and Ciphers: Julius Caesar, the Enigma and the Internet, Cambridge: Cambridge University Press, ISBN978-0-521-00890-7
• Tutte, W. T. (19 June 1998), Fish and I(PDF), retrieved 11 January 2020 Transcript of a lecture given by Prof. Tutte at the University of Waterloo