16,602 reputation
22470
bio website pwnhome.wordpress.com
location Earth
age
visits member for 3 years, 7 months
seen 4 hours ago

I like crypto. Need I say more?


May
21
revised how to use common modulus attack?
added 232 characters in body
May
20
reviewed Leave Open how to use common modulus attack?
May
20
answered how to use common modulus attack?
May
20
revised how to use common modulus attack?
added 26 characters in body
May
20
comment Advantages to knowing $p$ and $q$ in Blum Blum Shub?
Using CRT to speed up the computation?
May
19
revised Shamir's secret sharing scheme - type of channels
deleted 25 characters in body
May
16
awarded  Nice Answer
May
16
comment Shamir's secret sharing scheme - type of channels
Cleaned up some comments based on a mistake I had made on the 2nd part of the question
May
16
revised Shamir's secret sharing scheme - type of channels
deleted 74 characters in body
May
15
comment Computing youngest person among 3 while keeping ages private
@tylo, correct me if I am wrong, but aren't garbled circuits typically only used for 2 party computation? I think there are constructions for more than 2 party computation which use garbled circuits, but they tend to be less efficient than secret sharing based constructions.
May
15
comment Low level explanation of how a message is sent via RSA
You can send them together. You just have to specify a protocol format. It could be anything: a simple binary protocol (first N bytes are the encrypted key; remaining bytes are the ciphertext); xml; json; base64 encode each and put a newline in-between.
May
15
answered Low level explanation of how a message is sent via RSA
May
15
answered Shamir's secret sharing scheme - type of channels
May
14
comment How to benchmark custom crypto with OpenSSL benchmark suite?
You probably implement your primitive within openssl and make it one of the options for the test suite. As openssl is open source, it shouldn't be too bad right?
May
14
comment Is there a number of tries after which Hashcash is guaranted to be solved?
For a good hash function, the answer is no. Now, if instead you were interested in a probabilistic guarantee (say guaranteed with probably greater than P), I think you could come up with an answer.
May
14
comment Is AES key length a size of the key or entropy?
@codekiddy here is another article that might interest you.
May
14
comment Is AES key length a size of the key or entropy?
@codekiddy The symbols in the set of 256 take 8 bits each to represent in their most compact representation. How many bits does it take to represent the symbols in a set of size 3000? More than 8. So the key is no longer 160 bits. In other words, going back to your original example, unicode characters take more bits to represent than ascii characters, so in bits, the password will be longer even though you only draw 20 symbols in each case.
May
14
comment Is AES key length a size of the key or entropy?
@codekiddy "Entropy effectively bounds the performance of the strongest lossless compression possible" (src).
May
14
comment Is AES key length a size of the key or entropy?
@codekiddy Say there are 256 symbols in your symbol set and the length of the password is 20 symbols. If the symbols are chosen completely at random then the entropy of the password is $\log_2 256^{20}=160$, it also turns out that the length of the password is 160. You can't use that password directly as a 128 bit AES key since that key must have length 128. So what do you do? Out of necessity, you have to shrink the password from 160 bits to 128 bits. How do you do this without also shrinking the entropy to 128 bits? Answer: you can't.
May
14
revised Is AES key length a size of the key or entropy?
added 251 characters in body