Cryptography attack on two symmetric key

Duelz — Fri, 18 Nov 2011 12:12:11 +0800

Let say a tag and reader both uses key s1 and s2 .
For the reader to authenticate the tag , the reader will send encrypted n-bit challenge which is x xor s1.
The tag will then decrypt x xor s1 , and encrypt back x xor s2 sent to the reader
The reader will then authenticate if the decrypted x received is same as the encrypted x sent

reader -----------(x xor s1)-------------> tag
tag -------------(x xor s2 )--------------> reader

authenticate if the x value send by the reader is as same as the x value received when decrypted

by observing this a single implementation of algorithm,
i could find s1 xor s2 , which is x xor s1 xor x xor s2?
s1 xor s2 sort of salted together
but i cant find it individual key which is s1 and s2
any idea guys?

Keyboard software

Duelz — Sat, 19 May 2007 00:02:19 +0800

This my be a dumb question but is there keyboard software which enable multiple keys to be entered wif 1 key like entering "qwertyuiop" with juz a single "F1" key

Any recommendation is gladly appreciated

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Cryptography attack on two symmetric key

Keyboard software