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May
8
comment At what point can you you implement crypto algorithms?
@NeilSmithline Also power analysis.
Apr
6
comment What makes this mixer function resistant to differential cryptanalysis?
Makes sense! Do you have a reference that explains the part about invertible vs. non-invertible s-boxes for SPNs? It sounds like an interesting topic.
Apr
6
comment What makes this mixer function resistant to differential cryptanalysis?
@MaartenBodewes As I said in the post, I was "testing some other randomly conjured up designs" - this construction was just invented by me trying random things.
Apr
2
comment Are there any valid, and person readable, checksums possible?
I think OP is looking for something similar to the PGP word list.
Apr
2
comment What makes this mixer function resistant to differential cryptanalysis?
@Aleph Sorry, I'm not familiar with the term DDT. The s-box is just a randomly generated preset created by shuffling the numbers 0 to 255 - is it likely that this produced a good S-box in terms of differential properties?
Apr
2
comment What makes this mixer function resistant to differential cryptanalysis?
@kodlu 2, on an 8-bit input. Sorry, should've said.
Mar
16
comment Given only RSA public key parameters, what security issues might I be able to detect?
@yyyyyyy I was wondering whether somebody might mention shared factors and other such things. I don't know of any that have affected .NET compilers / IDEs, but I'd be interested to know if anyone has heard of such a thing (either in Microsoft .NET, Mono, or another implementation).
Mar
16
comment Can the same random number be used in encryption and signing?
Another reason is that if the implementation of the signature function is flawed (either in terms of the cryptography involved, or a side-channel attack) in a way that allows key recovery, the attacker would gain the ability to decrypt all messages because she inherently recovers the encryption key too. Where the two keys are distinct, she only gains the ability to forge messages (which may or may not be useful, depending on ciphertext malleability).
Mar
16
comment Where I can find a list of certified software / hardware RNGs compliant to NIST SP 800-22?
I would imagine that you'd need to get your implementation certified, in situ within your product.
Mar
16
comment What is the most light-weight symmetric cipher thats still usefull?
What are your actual limitations? The answer(s) to your question greatly depend on your platform, and how limited your ROM and RAM are.
Mar
16
comment Where I can find a list of certified software / hardware RNGs compliant to NIST SP 800-22?
According to this page, NIST certifies four DRBG techniques, and no NRBGs. It doesn't seem that they've explicitly certified any implementation.
Mar
16
comment CCA-attack is possible in RSA, but how the decryption key $d$ is known to anyone
Are you talking about Bleichenbacher's ACCA attack? My understanding is that it's a padding oracle attack against PKCS#1, which inherently affects RSA, rather than an attack against RSA itself.
Jul
16
comment Can I crack an AES string if I have all these parameters?
@Matthew ... and verify that the result is correct by doing statistical analysis. Remember that AES decryption with incorrect keys just gets you a bunch of incorrect plaintext bytes.
Jul
15
comment Galois field step in XEX mode
Surely $2^n$ over $GF(2^{128})$ is equal to $2^n\ mod\ 2^{128}$?
Jul
15
comment Galois field step in XEX mode
@mikeazo If you look, that question you linked was asked by me.
Mar
25
comment Is PBKDF2-HMAC-SHA1 really broken?
Surely it should be a required property? Does it not reduce the potential for brute-forcing alternative passwords?
Dec
22
comment With Encrypt-then-MAC, and flexible protocols, do I need to authenticate the authentication?
I recommend that this question is moved to Cryptography SE.
Dec
4
comment Is a simple stream cipher “partially homomorphic” if no integrity check is applied?
This makes sense. I think malleable was the term I was originally trying to think of to describe this property.
Dec
4
comment Is a simple stream cipher “partially homomorphic” if no integrity check is applied?
Does that requirement imply that there are no truly homomorphic symmetric ciphers, since generating the second ciphertext would require knowledge of the key?
Jul
9
comment Selecting bijective functions for permutations
@CodesInChaos Surely those first operations aren't sufficient? I understand the s-box somewhat, though from my understanding it's a transposition of smaller chunks rather than the entire block.