Cryptography From Keys to Databases—Real-World Applications of Secure Multi-Party Computation

---

From Keys to Databases—Real-World Applications of Secure Multi-Party Computation Posted: 16 Dec 2018 03:17 PM PST submitted by /u/vamediah [link] [comments]

An idea on XOR cipher. Posted: 16 Dec 2018 05:25 AM PST First of all, I don't know that much about cryptography, but I'm really interested in the subject. Probably this method already exists; if so, please, let me know in the comments so I can learn more about it. Also, if it doesn't exists and you know a way to break the cipher, let me know as well. ​ The big issue with XOR is frequency analysis, so I came up with this idea that, as far as I'm concerned, should make frequency analysis useless, leaving only brute force attacks. ​ Given a byte array: [65, 66, 67, 68, 69, 70] ("ABCDE") Starting at position 1, add the previous value and then mod 256, resulting in: [65, 131, 198, 10, 79, 149]. Now, XORring with a repeating key (for instance, [104, 121, 117, 105] ("hyui")) should give a final ciphered array with no possibility of running frequency analysis on. In this case, [41, 250, 179, 99, 39, 236]. The deciphering will be similar, XOR again, and perform a byte substraction backwards. ​ Here's an implementation in Python: #!/usr/bin/env python2.7 def xor(msg, key): for i in range(len(msg)): msg[i] ^= key[i%len(key)] return msg if __name__ == '__main__': msg = 'ABCDEF' key = 'hyui' msg = [ord(i) for i in msg] key = [ord(i) for i in key] # Encrypting print msg for i in range(1, len(msg)): msg[i]+=msg[i-1] msg[i]%=256 print msg msg = xor(msg, key) print msg # Decrypting print '' msg = xor(msg, key) for i in range(len(msg)-1, 0, -1): msg[i]-=msg[i-1] msg[i]%=256 print msg The execution is: [65, 66, 67, 68, 69, 70] [65, 131, 198, 10, 79, 149] [41, 250, 179, 99, 39, 236] [65, 66, 67, 68, 69, 70] ​ submitted by /u/jlxip [link] [comments]

You are subscribed to email updates from Cryptography news and discussions. To stop receiving these emails, you may unsubscribe now.	Email delivery powered by Google
Google, 1600 Amphitheatre Parkway, Mountain View, CA 94043, United States