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1h
comment Retrieve value of private key after encryption with the public key
Obviously raising the modulus to the public key exponent modulo the same modulus does make zero (sense) :P
10h
comment Is MCrypt's 8-bit OFB mode secure?
www.distorted.org.uk just returns It works!. On the good side, IACR is reputable, the paper doesn't look anything like snake oil and he seems to have worked with Philip Rogaway.
10h
comment Is MCrypt's 8-bit OFB mode secure?
The problem with that paper is that I cannot find any references to it, nor any notions of peer review. The author talks of "we" but I see only one author mentioned. It doesn't seem to be published by a major institution either. I'm not saying that the paper is incorrect in any way but I would not accept all the conclusions without another good look. If you have any pointers to peer reviews please include them!
11h
comment Is MCrypt's 8-bit OFB mode secure?
Ignoring the weirdness of a library supporting an encryption mode that its own developers describe as "insecure" and recommend "not to use it" -- what's so strange about that? You can include it for completeness and - more importantly - backwards compatibility. Kudos to the developers to mention that it shouldn't be used. Same goes for 8 bit CFB mode of course, if just for reasons of efficiency.
14h
comment Prove there is PRG that is not necessarily one-to-one
Probably correct if dropping bits of the input is allowed. I presume it is, but in general you would expect that a random number generator behaves differently for different seed input. Can anybody confirm?
2d
comment What is a Key Derivation Function?
This is probably not a "more formal security definition" of a KDF.
2d
comment What is a Key Derivation Function?
The missing key expansion, the focus on passwords and the fact that it certainly is not formal as requested made me vote down this answer.
2d
comment What is a Key Derivation Function?
@user4982 If you could post an abstract of that text together with your link than it would make an excellent answer.
2d
comment RSA modulus (N) from public key and calculating N from p, q not equal
Meh, try new BigInteger(1, bp);, same for all other BigInteger calls.
Apr
14
comment RFID Protocol Cryptanalysis
4 bit keys? No countermeasures? What do True or False mean? How is the tag identified? You cannot analyze this scheme without more information.
Apr
13
comment What are the difference between cryptographic primitives and encryption primitives?
I think it should be cryptographic- instead of cryptography primitives.
Apr
13
comment What are the difference between cryptographic primitives and encryption primitives?
@StephenTouset I think that's an answer.
Apr
13
comment (Simple) Tool for analysing performance (speed in particular) of cryptographic hash function?
So? Insert your own code and make a separate openssl speed mysha256 CLI. Yes, in this case SHA-256 is embarrassingly linear, so you can just test using your own code and a timer. Only disadvantage seems to be that the reporting is missing (but I guess there are plenty tools to handle CSV files with timings).
Apr
13
comment Standards/RFCs for non-Diffie-Hellman perfect forward secrecy?
possible duplicate of What is the post-quantum cryptography alternative to Diffie-Hellman?
Apr
13
comment Standards/RFCs for non-Diffie-Hellman perfect forward secrecy?
ECC-RSA? Elliptic RSA variants? Do you mean algorithms such as ECDSA for signatures or ECIES for encryption? It seems the trick is in the authentication, not so much the key agreement.
Apr
12
comment (Simple) Tool for analysing performance (speed in particular) of cryptographic hash function?
Would have answered the same way on StackOverflow :)
Apr
11
comment Would a pictographic, phoneme-based, hand cipher be difficult to crack with computer crypt-analysis?
What, in case we have to rise against the machines?
Apr
9
comment Randomness in generation of Virtual Machines from pre-built Image
Well, you can always rely on RDRAND if you are really worried. Just make sure your client OS supports it and that you have got Intel hardware. For instance, this was found for VMWare: "Support for RDRAND was introduced with virtual hardware version 9. As long as your virtual machine has virtual hardware version 9 or greater and RDRAND is available on your physical CPU, it will be available to the guest."
Apr
9
comment BER or DER X9.62 ECDSA signature
The SEC1 document just uses DER as example and specifies only ASN.1 - that's still not very conclusive. DER may be the de facto standard.
Apr
8
comment How does the certificate authority generate a signature F?
When uncertain, look up the standard: "signature is the result of signing the certification request information with the certification request subject's private key" (section 4.2 of RFC 2986, for which the link is strangely broken)