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May
16
revised Elliptic curve brute forcing
edited body
May
15
reviewed Reject Does the plaintext have to be at least as long as the key in Polyalphabetic substituion cipher
May
15
reviewed No Action Needed Encryting data with password for local storage using libsodium
May
15
reviewed No Action Needed A timestamping authority (digital notary)
May
15
reviewed Leave Open At what point can you you implement crypto algorithms?
May
15
reviewed Leave Open what is the public information in Elliptic curve cryptosystems
May
15
reviewed Leave Open Commitment scheme to share money
May
15
comment How do we know one-way functions can be iterated?
How is this a cryptographical question?
May
15
answered Modifying a [CRC32] checksum protected file
May
15
comment How can one improve Rijndael's with more efficient SBoxes?
"A Hamming weight of about the half of the word size". Unless you're going to change how the sbox is used within AES, the sbox needs to be invertable (otherwise, decryption is a bit tricky), and so all 256 outputs (including the ones with hamming weight 0 and 8) must be possible.
May
15
comment How do we guarantee plaintext is coprime in RSA?
And, as fkaiem points out, even if N and P aren't coprime, it turns out RSA works out as well, as $x^{ed} \equiv x \pmod{N}$ for all $x$, including those not relatively prime to N
May
14
comment SHA-512 partial preimage
Write a quick program that selects a preimage, calls OpenSSL to generate the SHA512 hash, then look at the value it generated; if it didn't start with the value you were looking for, try again with a different preimage. You can optionally keep a count of how many iterations you go through before you succeed.
May
14
comment SHA-512 partial preimage
Perhaps OpenSSL...
May
14
reviewed Edit
May
14
revised
The problem of determining whether a given boolean expression is either true or false is trivial;
May
14
reviewed No Action Needed Commitment scheme to share money
May
14
reviewed No Action Needed Calculating XOR Key Sizes
May
14
answered what is recommended x length in Diffie Hellman algorithm
May
14
comment Why doesn't this defeat RSA?
Becsuse $ed'-1$ is (in general) not a multiple of the order of the group, which is $lcm(p-1,q-1)$
May
14
comment Why doesn't this defeat RSA?
In the example you cited $8^{26} = 47 \bmod 187$, and not $2$