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Apr
7
revised What use is the signature without the message under RSA?
expand
Apr
7
revised What use is the signature without the message under RSA?
polish
Apr
7
revised What use is the signature without the message under RSA?
Explain how to make forgeries, clarify
Apr
7
revised What use is the signature without the message under RSA?
added 2 characters in body
Apr
7
answered What use is the signature without the message under RSA?
Apr
3
comment Crack linear congruential generator knowing every other word in sequence
@Gravian: hints: The algorithm you used (successfully I guess) can obtain a multiple of the actual $m$. The right $m$ is likely not too much above the highest output available.
Apr
3
comment Crack linear congruential generator knowing every other word in sequence
Hint: compute $X_{n+2}$ as a function of $X_n$; suprises, that's a standard LCG with the same $m$, and you know consecutive output for it. From that find $a'$, $b'$, $m$ for that other LCG using a standard method, then from that derive $a$, $b$ of the original.
Apr
3
revised The effect of truncated hash on entropy
make proof more rigorous
Apr
3
revised The effect of truncated hash on entropy
fix a formula
Apr
3
comment Required key size for an ideal cipher with a 32 bit block size
$\log_2(2^{32}!)\approx131,242,625,471$ bit. Storing that key for would require slightly less than 16GiB. It is quite easy to make a program implementing such a theoretically perfect 32-bit block cipher; the challenging thing is to make it bearably fast.
Apr
3
revised The effect of truncated hash on entropy
further polish
Apr
3
revised The effect of truncated hash on entropy
add missing word
Apr
3
revised The effect of truncated hash on entropy
Make the proof hopefully fully rigorous
Apr
2
awarded  Enlightened
Apr
2
awarded  Nice Answer
Apr
2
revised The effect of truncated hash on entropy
cleanup
Apr
2
revised The effect of truncated hash on entropy
better proof
Apr
1
revised Is computing roots moduli a composite $N$ a hard problem without knowing the factorization of $N$?
Attempt to address comments
Apr
1
revised Is computing roots moduli a composite $N$ a hard problem without knowing the factorization of $N$?
Attempt to address comments
Apr
1
comment Is it safe to encrypt random data using ECB mode?
Perhaps, in the second paragraph: reasonable amounts of random data