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Mar
31
comment TLS/SSL's usage of Non-Ephemeral DH vs DHE
A diffie-hellman public key will, when encoded for a X.509 certificate, be coupled with it's domain parameters, which includes the prime modulus $p$, generator $g$, group order $q$ and (optionally) co factor $j = (p-1)/q$. An EcPublicKey is otoh commonly coupled with an object identifier signifying which standard group the key belongs to, such as P-256, P-521 etc.
Mar
31
answered TLS/SSL's usage of Non-Ephemeral DH vs DHE
Mar
29
comment What might be assumed about a PRF if the key has been chosen?
@D.W. TLS 1.2 specifies a generic PRF based on HMAC with a configurable hash function. This composition is called TLS PRF. It is recommended with a "SHOULD" for new cipher suites, but might, technically, be replaced in additional cipher suites defined in other RFCs.
Mar
28
comment What might be assumed about a PRF if the key has been chosen?
FTR, I am personally not sure including the handshake hash in the master_secret is the right way to go, in order to prevent the secure-resumption family of attacks, in particular if the adversary might participate in the design of the cipher suites. I might however be over cautious and would appreciate some input.
Mar
28
revised What might be assumed about a PRF if the key has been chosen?
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Mar
28
comment What might be assumed about a PRF if the key has been chosen?
@RickyDemer: So the answer is "no" and "no"?
Mar
28
revised What might be assumed about a PRF if the key has been chosen?
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Mar
28
revised What might be assumed about a PRF if the key has been chosen?
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Mar
28
asked What might be assumed about a PRF if the key has been chosen?
Mar
27
comment Any field in a PKI certificate where some text info can be stored?
This is off topic, but the most common acceptable way would be for the issuer to include the text in the Subject name of the issued certificate. The "right" way, however, is to add a Certificate Policies extension, and add a link to a web site with the information you want to associate with the certificate.
Mar
24
awarded  Nice Answer
Mar
17
comment Hash Based Encryption (fast & simple), how well would this compare to AES?
Why did you mark the first entry as a duplicate?
Mar
17
comment Hash Based Encryption (fast & simple), how well would this compare to AES?
@fgrieu: You are right, related key attacks against SHACAL-2 is an independent topic, and it has been studied.
Mar
17
revised Hash Based Encryption (fast & simple), how well would this compare to AES?
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Mar
17
answered Hash Based Encryption (fast & simple), how well would this compare to AES?
Mar
3
answered How does TLS generate the shared secret?
Mar
1
comment Need Help Reversing my Encryption Algorithm
This is off topic, because any answer would be of little or no use to anyone else. If you want to read up on one common way of making encryption algorithms invertible, you could e.g. check out en.wikipedia.org/wiki/Feistel_cipher
Feb
24
comment $f : \mathbb{Z}_n \rightarrow \mathbb{Z}^\times_n$?
Perfectly correct, thanks.
Feb
24
comment $f : \mathbb{Z}_n \rightarrow \mathbb{Z}^\times_n$?
$n$ that is a product of the smallest primes is a 'worse' case than powers of $2$.
Feb
24
comment $f : \mathbb{Z}_n \rightarrow \mathbb{Z}^\times_n$?
If $GCD(x-1,n) \neq 0$, then $f^{-1}(x) = x$. Otherwise, if $GCD(x-2,n) \neq 0$, then $f^{-1}(x) = \{x-1,x\}$ etc. I think this recursion has an estimate worst case running time of $ln(n)$.