154 reputation
111
bio website google.com
location Stack Overflow
age 31
visits member for 1 year, 10 months
seen Oct 17 at 4:16

I post stuff on stackoverflow and want a free profile badge for filling out this section :D


Sep
20
comment PKCS1 and blind RSA signatures
@CodesInChaos - that jibes with my understanding. Although I'm not sure why a probabilistic padding scheme would be bad? I'm also unsure of why, when you already have a hash, blinding is necessary, since the hash pretty much obscures the message already. I guess I'll start a new question for that lol
Sep
18
comment PKCS1 and blind RSA signatures
Also, it seems to me that it necessarily needs to be broken up anyway. If you were going to sign the message wouldn't be a blind signature. It'd be a regular signature. So you pad the message, don't do RSA, blind it, and then send it off to the signer for them to sign it. But since they're signing a blinded message they wouldn't know what the original message was. Of course since you're sending a padded hash it seems to me that they wouldn't know what the orig message was anyway. Unless I'm totally misunderstanding blind signing.
Sep
18
comment PKCS1 and blind RSA signatures
You do EMSA-PKCS1-V1_5-ENCODE, blind and then do modular exponentiation. RSASSA-PKCS1-V1_5-SIGN is EMSA-PKCS1-V1_5-ENCODE and modular exponentiation. Blinding has to be done in the middle of those two, it seems to me, hence my saying you have to side-step RSASSA-PKCS1-V1_5-SIGN.
Sep
17
comment PKCS1 and blind RSA signatures
I'm not proposing unpadded rsa. I'm proposing doing EMSA-PKCS1-v1_5-ENCODE but not the full blown RSASSA-PKCS1-V1_5-SIGN
Dec
15
comment creating a small number from a cryptographically secure random string
I think you're right Thomas in that a typo was made. With (N / K) * K the K's would cancel each other out leaving you with N, which X is already pretty much guaranteed to be less than.
Dec
15
comment ANSI X9.31 standards for generating random numbers
Is there some reason DES in counter mode shouldn't instill confidence? I could lack confidence over RSA encryption with a 4096-bit key but I'd probably be silly to do so without a specific reason..
Dec
14
comment ANSI X9.31: the purpose of the date/time vector in the PRNG?
What if v* isn't a fixed secret? Plus, it seems to me that Ek() would need to have random keys / IVs anyway so if you could generate a random key / IV with what's available in your entropy pool why not just do the same for V*?