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Mar
27
comment Practical brute-force attack on 128 bit encryption
@user40602 Half of $2^{128}$ is $2^{127}$, not $2^{64}$, just like half of $2^{16}$ (65536) is $2^{15}$ (32768), not $2^8$ (256). Hopefully that clears it up.
Mar
24
comment What is this cryptosystem called?
@ShamminujRahman "Snake oil" is a colloquial term for "this sucks and is a scam, don't use it". [I haven't read the paper, but am just explaining the meaning of the term for OP]
Mar
21
comment Security of simple Skein PBKDF mentioned in the paper
@504811E In other words, memory usage is already independent of the length of the input.
Mar
21
comment Security of simple Skein PBKDF mentioned in the paper
@504811E There's no need to tweak it, that's how it already works by default: the "normal" implementation is one "initialization" function, an "update" function that you can call as many times as you want with successive input strings (that get processed sequentially) and a "finalization" function that returns the final hash for all the input data passed to the update function calls. The function that takes in a single buffer is a convenience function for when all the data is known in advance or is small enough and just happens to only call the update function once.
Mar
21
comment Security of simple Skein PBKDF mentioned in the paper
Why would it be memory-hard? The hashing code only processes one block at a time, you don't need the entire input in memory all at once (otherwise hashing 20Tb files would be quite challenging).
Mar
19
comment Of what use is my code for finding prime numbers of a certain size?
@user24719 "it wouldn't be rapid" is an understatement, there physically wouldn't be enough energy in the entire universe to carry out the computation.
Mar
16
comment Reusing a one-time pad?
XORing the data with a 16-byte key is not nearly good enough... unless your file is made up of random data that kind of encryption is very easy to break.
Mar
16
comment why do files downloaded with http and https have the same size?
Actually OP seems to be misunderstanding that the whole encryption/decryption (and even compression/decompression) process is done transparently for the user, i.e. when a file is delivered compressed by a server the client decompresses it before giving it to the user, it doesn't just drop the gzipped file into the download folder for the user to deal with. At least that is how I understood the question after it was updated.
Mar
14
comment Of what use is my code for finding prime numbers of a certain size?
PrimeQ is also of interest.
Mar
14
comment Of what use is my code for finding prime numbers of a certain size?
@dave_thompson_085 Or even in this universe...
Mar
11
comment What is the probability of finding 4 equal bytes?
This is really barely on-topic since you could argue the question involves information entropy, but it should actually be on math.stackexchange.com.
Feb
27
comment Exponentiation with fully homomorphic encryption
crypto.stackexchange.com/questions/15436/…?
Feb
17
comment Given infinite unencrypted and encrypted texts, can I find the algorithm?
? stream ciphers don't necessarily have keys as long as the message, e.g. see RC4, and block ciphers can have modes of operation that effectively turn them into a stream cipher construction.
Feb
8
comment Are passwords generated from sine vulnerable to certain attacks?
In fact, by posting this question on SE, Steve may have inadvertently reduced his friend's password security to zero (if it wasn't zero to begin with).
Feb
8
comment Is $f(x)\oplus x$ a one-way function?
@PaŭloEbermann If one-way functions don't exist then the question is vacuous since it is predicated on $f$ being a one-way function :)
Feb
6
comment Why is knowing M not enough to break Blum Blum Shub?
What makes you think $x_n$ is available to you? :)
Jan
27
revised blake2 wiki excerpt
added 138 characters in body
Jan
26
comment How does BLAKE2 ensure that hash(A) != hash(B) when B = A||0 and both A & B have the same number of blocks?
[created the tag for you]
Jan
26
wiki created blake2 excerpt
Jan
26
suggested approved edit on blake2 tag wiki excerpt