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1h
comment nonce of AES-GCM in SSL
@SEJPM Thanks for the update, but isn't that what's already in the answer (first to last paragraph)?
1h
comment How often does RSA-OAEP have a leading zero?
Important note: it can also have more than 1 leading zero (2 bytes more than 1/65536 of the time, of course etc. etc.). The chance that there are more than 8 leading zero's is negligable ($2^{64}$), 16 leading zeros is next to impossible given that the encryption routine is correct. I can still remember the phrase: "OK, we've fixed the leading byte problem" pretty well - that's not enough.
4h
comment Suggestion : CRC vs SHA1
A CRC is enough to protect against random changes. What you seem to be protecting against is a system where a lot of data may be changed in one go, without an attacker being able to chose the input of the checksum. In that case a large CRC could be possible. Assuming that the CRC32 is randomly distributed you would get a change of 1 in $2^{32}$ (or 1 in 4 bilion) that the CRC verifies for incorrect input.
1d
comment What is SRP-Z form?
From the terms I understand that this is mutual authentication while SRP itself is client only authentication. If you mix in a server secret in the session key derivation then the above description may make sense. Did you search the patent database for SRP?
1d
comment Collision attacks on digital signatures
I think the text in the question shows a clear underestimation about how easy it is to include a "jumbled mess" inside a file. I created a shell script that simply put the jumbled mess behind the executable code. Same MD5, script performed two entirely different things.
1d
comment Source for PKCS#11 Header Files
Don't see them either. If in doubt, kindly ask the authors.
2d
comment Ring signatures in ECC
@geoff_h That didn't work but you can always create your own answer. You won't get any points accepting it, but if you respond to this comment then I would be happy to upvote (if it is good, of course). A belated welcome to crypto, these are exactly the questions we are waiting for.
Jun
28
comment HMAC-SHA1( secret key ) with header of a transmitted file
Please note my question here though.
Jun
28
comment Do all attacks against PKCS1 v1.5 encryption require an oracle
To be very precise that would be RSAES-PKCS1-v1_5 that uses EME-PKCS1-v1_5 encoding, according to PKCS#1 v2.1 specifications. Not used much, but it doesn't leave any doubts to what scheme is being used.
Jun
28
comment Can I use HKDF to improve security of HMAC used with weak hash function?
Sometimes you have to fiddle if the solution space is otherwise empty. But if you can leave it to experts such as DJ Bernstein -> NaCl then all the better. If you keep using HMAC then don't forget to include the IV.
Jun
28
comment RSA Signature Forgery
There is a reason why even the authors of PKCS#1 went out of their way to create a different name for modular exponentiation as used for signature generation and encryption. "I named it as an encryption" is the same as saying "I think I know better than the authors or RSA on how to define the terms". Please stop the confusion.
Jun
28
comment Accelerated hashing on consumer-grade CPU?
@RichieFrame Almost no consumer CPU supports hardware accelerated hash instruction, as the VIA Eden processors do. They are however not known particularly for speed, so the mileage may vary.
Jun
28
comment Getting the encryption/has algorithm used for modem configuration file
Thanks for reporting back. This seems more a modem specific hack than an answer to the question though.
Jun
28
comment Block Ciphers - Standardize plain text
@RickyDemer PKCS#7 padding seems to be the industry default (I like bit padding better too). Please post an answer instead of putting an answer in a comment like this.
Jun
28
comment Do all attacks against PKCS1 v1.5 encryption require an oracle
Very much related, older article on the security site: What specific padding weakness does OAEP address in RSA?. Note that the padding oracle attack is known as "Bleichenbacher's attack".
Jun
28
comment Do all attacks against PKCS1 v1.5 encryption require an oracle
You're welcome, K. Biermann. We're still migrating out of beta, but we're up and running for sure. Always keep side channel attacks in mind when talking RSA - but that goes as much for OAEP as for PKCS#1 v1.5 padding.
Jun
27
comment Getting the encryption/has algorithm used for modem configuration file
You could simply ask the modem manufacturer; indicate you require this information to do a security audit.
Jun
27
comment HMAC for encrypted authentication token: recommended iteration number
@otus I think that the consensus now is that the question can be closed, not deleted if an answer on another question covers the question put forward. That's more of a meta discussion though.
Jun
25
comment This paper was slid under my door and I dont know who else to ask if it has any meaning besides you guys
A not too well written note by somebody who's signature and humor is strongly underdeveloped. I would expect a juvenile.
Jun
23
comment what are the most common stream ciphers algorithms?
AES-CTR is certainly not a block cipher, poncho :P Maybe a block cipher mode of operation that turns the block cipher into a stream cipher. More constructively, we may want to include A5/1 but I guess it's unlikely to be the source of a ciphertext that has been found somewhere.