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Jan
24
answered Hashing a password before using for online accounts
Jan
24
comment Why do we implement a protocol?
Interesting to see that you do implement to find out the bottlenecks, that's something I would usually not expect. Anyway, both answers conclude that it would be a good idea to provide implementations of a protocol ... which reminds me that I should finish one sooner rather than later.
Jan
24
revised Which cryptography technique does not increase the size of the plain data?
added a link to an explanation of ymmv for people unknown to internet lingo
Jan
24
awarded  Nice Answer
Jan
23
revised System parameters in identity-based encryption
added 11 characters in body; edited tags
Jan
23
comment Why do we implement a protocol?
@DavidRicherby The problem - if I understood correctly - is that there were too many web related protocol standards that had issues when implemented (in e.g. a browser) - if they were implemented at all. So after a while they did the sensible thing and required an implementation. W3C doesn't however just standardize protocols after they have been in frequent use (for the first forms of HTML this was obviously the case, but not for many of the protocols that came after that, such as XHML / HTML 5).
Jan
23
revised Why do we implement a protocol?
added 245 characters in body
Jan
23
answered Secure Key exchange using javacard applet
Jan
23
answered Why do we implement a protocol?
Jan
23
comment Is HMAC-MD5 considered secure for authenticating encrypted data?
You can find answers about the security of HMAC-MD5 in general by following this link.
Jan
23
comment Is HMAC-MD5 considered secure for authenticating encrypted data?
Of course, if you think you can provide an answer better /easier to understand than the one of fgrieu then you're welcome to post there...
Jan
23
comment Is HMAC-MD5 considered secure for authenticating encrypted data?
Under the deleted answer: " Happy to vote this up in a separate Q/A. I guess we would have to change the title of this question as well if a separate question is posted to show that this question was specific to authentication & integrity validation of data. E.g. "Is HMAC-MD5 secure for all purposes?" and "Is HMAC-MD5 secure for authentication of data?". – Maarten Bodewes May 11 '15 at 18:09 "
Jan
23
comment Is HMAC-MD5 considered secure for authenticating encrypted data?
Sorry, that was my previous comment as well: see Q/A here
Jan
23
comment Is HMAC-MD5 considered secure for authenticating encrypted data?
You can create a separate question, e.g. "When is HMAC-MD5 not considered secure?" and self-answer it if you like. It would be on topic that way (I haven't looked for dupes yet). Then you can always point to it from a comment under the question.
Jan
23
comment Is HMAC-MD5 considered secure for authenticating encrypted data?
Yes, there was already this kind of answer until it got deleted. The question explicitly states "for authenticating encrypted data". The use for calculating checksums and the availability of the key are perpendicular to that part of the question. Welcome to crypto anyway, these kind of well written answers are very welcome here!
Jan
23
comment Plaintext and ciphertext block sizes
Be warned that this question is only valid for toy ciphers that use raw / textbook RSA. You'd better use AOEP and a large key size for solving actual RSA problems.
Jan
23
revised Best attack on double DES followed by XOR with third key
edited title
Jan
23
comment Best attack on double DES followed by XOR with third key
@otus Could be, but I made the title describe the method explicitly. With just one XOR I'm not 100% if whitening applies. Given the question, I'm not sure if we should use the term "key whitening" in the question title (it's fine in answers of course).
Jan
23
revised Best attack on double DES followed by XOR with third key
edited title
Jan
23
comment Best attack on double DES followed by XOR with third key
@otus Hmm, yes, it's more like a multiple-time pad. Does that term exist? Changed title again, sorry for the confusion.