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2d
comment Statistical tests for PRNG that generates a sequence which is not binary
@fkraiem I think the point is per the test, not how the output can be represented. Since the algorithm may naturally output data in a base that is not 2, a statistical test should be relevant to that particular base, as well as to bitstreams. Ent for example only tests bits and bytes, not arbitrary n-ary sequences
2d
comment Is there any symmetric key cipher (block or stream cipher) providing partial decryption?
I actually remember reading something like this, specifically in regards to compressed video, the least significant bits of quantized data were encrypted so a key was required to unlock the quality
May
3
comment What kind of analysis can I perform on my implementation of Salsa20 and Rabbit ciphers?
"I would like to perform some tests where I compare the plaintext and ciphertext and note any observations" I doubt that will get you anywhere
Apr
30
comment Dynamic Password Making
I use a similar idea, it uses TOTP and HOTP together, and changes approx every 100s. It combines a block cipher and a hash algorithm to get the job done. I will write up more details later
Apr
29
answered What would happen to AES if we replaced MixColumns with ShiftColumns?
Apr
29
comment Symmetric cipher speed (AES vs Camellia vs Twofish)
While I am a fan of Twofish for max security, AES on modern processors will be substantially faster, at least 5 times, maybe 10 times faster
Apr
28
comment What would happen to AES if we replaced MixColumns with ShiftColumns?
wouldnt that just shuffle all the bytes in a very predictable way?
Apr
28
comment Is the use of a 4-round Blake2b permutation in OPP justified?
for use in a hash function it would be broken, but for use in a block cipher environment it should be fine, NORX is also 4 rounds of essentially the same permutation. I do however prefer a keyed permutation in an XEX cipher
Apr
27
comment mode of operation in cryptography
As the answers suggest: e. none of the above. I would go for OCB or GCM within a secure protocol
Apr
27
comment How robust is my coded output?
occasionally, members of the sci.crypt newsgroup will look at a cipher design, if it is interesting, and you have done a good job at describing it so that coming to an understanding of how it works is quick and easy.
Apr
27
comment Length of encryption password aes-256-cbc
given the wording of the question, it appears you have a misunderstanding of how all this stuff works. AES-256 uses a 256-bit key, thats where the 256 comes from, and if you are choosing a random key, there is no password
Apr
27
comment Key size for HMAC-SHA256
You could always expand a 256-bit key with a 512-bit hash such as SHA512, if you do not have a shortage of cpu power
Apr
27
comment Do you need a HMAC if decryption attempts are severely limited?
"At first decryption failure" how do you know that it failed? Any CBC encrypted message should decrypt with any key, even if the data is invalid, which is one point of the HMAC, to detect if the ciphertext has changed in transit. You could further truncate the HMAC from 32 bytes to 10 bytes, and still retain min security.
Apr
26
comment Using a straight password for encryption and authentication
I would say that it strongly depends on the precise methods used
Apr
26
comment What are the time considerations with regard to security against birthday attack?
80-bit security was considered minimally secure (that is now 112-bit), which equates to a 160-bit hash (now 224-bit)
Apr
26
comment Is there a function that can be used to satisfy collision resistant property in MAC?
I assume you already looked at the myriad of cryptographic hash functions, what about them was unsuitable?
Apr
26
comment Is there any function that does not suffers birthday problem?
When the birthday bound exceeds the number of atoms in the universe, do you still consider that "suffering from the problem"? For example, a 576-bit hash function
Apr
26
comment When to chose hardware accelerated crypto for Big Data
@Demetri Nahelem processors like the W5590 do not have AES-NI
Apr
26
comment When to chose hardware accelerated crypto for Big Data
@Blaze thats how the NSA got google's data, because they werent encrypting the data in transit within the data center
Apr
26
comment MAC is constructed by hashing and then encrypting
what exactly is option 2 supposed to be?