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Jan
2
revised What is total key space in transposition algorithms
create new transposition-cipher tag
Dec
28
comment Why xor is a linear operation but ordinary adding is not
Nitpick: the integers with ordinary addition modulo 256 are not a vector space over any finite field. In fact, they're not a vector space at all, although they are an abelian group, and therefore a module over the ring of integers.
Dec
27
revised How to attack this authentication protocol from “Cryptography: An introduction”
edited tags; edited title
Dec
27
answered How to attack this authentication protocol from “Cryptography: An introduction”
Dec
27
revised What does this Authentication protocol achieve and what information is shared?
more $$$$ (and a few {{}})
Dec
27
comment How to attack this authentication protocol from “Cryptography: An introduction”
Ps. Where is this exercise from, anyway?
Dec
27
comment How to attack this authentication protocol from “Cryptography: An introduction”
possible duplicate of What does this Authentication protocol achieve and what information is shared?
Dec
27
revised Two-dimensional S-Box
edited tags
Dec
27
answered Using HMAC to secure a “widget”
Dec
27
comment Off-the-record communication
@RamRachum: No, because that would lose the deniability property we wanted in the first place: for a given $W' = W \oplus SHA(m) \oplus SHA(m')$, finding $Y'$ and $Z'$ such that $W' = H(Y' + Z')$ (for any meaning of $+$) would require breaking the preimage resistance of $H$.
Dec
27
reviewed Approve Off-the-record communication
Dec
25
comment Off-the-record communication
@RickyDemer: Good point. $\hspace{400px}$ But honestly, what's the deal with $\hspace{300px}$ the random $\hspace{240px}$ MathJax spaces, anyway? $\hspace{200px}$ $\hspace{200px}$ You know it doesn't really look the same $\hspace{100px}$ to anyone who doesn't have the exact same browser and fonts as you $\hspace{250px}$ anyway, right?
Dec
25
answered Why is time-lapse cryptography not popular?
Dec
24
revised Hash function based on pseudorandom functions and security
edited tags
Dec
24
revised A situation where security by obscurity might be the best solution - or am I wrong?
edited tags
Dec
24
revised Acceptable assumptions when proving security
edited tags
Dec
24
revised Secure use-cases of block cipher with 64-bit block size
edited tags
Dec
24
revised Composition of block ciphers and 3DES
edited tags
Dec
24
revised Have these compositions of block ciphers the same security?
edited tags
Dec
24
revised Is a small size block cipher usable?
edited tags