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location Netherlands
age 40
visits member for 3 years
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Security professional with many years of experience with the practical application of cryptographic algorithms and protocols. I'm helping with the design of protocols and API's within international standardization bodies. Lead developer of a common criteria certified product. Over 30 years of general experience with computers.

Currently looking for a new position in the Netherlands.


Dec
22
comment Why shouldn't I use ECB encryption?
Hmm, first guess probably right: github.com/h3xstream/find-sec-bugs/blob/master/plugin/src/main/…
Dec
22
comment Why shouldn't I use ECB encryption?
@Rogue It requires Java 8 or an installed Bouncy Castle provider. Known as "AES/GCM/NoPadding".
Dec
22
comment Why shouldn't I use ECB encryption?
Interesting, what software generated that particular warning? FindBugs, PMD?
Dec
21
comment OpenSSL des-ede3 not producing same output as test vector implies it should be
Now that's just funny, finding a typo in one of the DES test vectors, and an evil one at that 666 indeed :)
Dec
13
comment Bae64 with shuffled alphabet
You know far more than that. For instance XML is text, so expect printable characters. There will be a lot of greater than and less than signs but also the equals operator and quotes are likely abundant because of tag attributes. And then there is the whitespace as well - lots of spaces and/or tab characters and possibly end of lines (using the double \r\n used for Windows, so if they are present you have two characters in a row!). Of course the bits are distributed over the 3 bytes encoded as 4 characters, but that could be advantageous as well.
Dec
9
comment MD-compliant hashes don't really accept arbitary length input, do they?
I think it won't scale that high on the list of MD5 deficiencies if it's not MD-compliant with regards to this. It would be fun though if you could generate a collision after 2^64 cycles, some kind of MD5 "time bomb" :)
Dec
7
comment suitable programming language for cryptography algorithms
That would have been the swap file or partition.
Dec
6
comment SHA1 Collisions - what about practical attacks?
Yeah, IAIK did try a distributed collision finding approach some time ago, and I even spend some CPU cycles on it, but it didn't lead to a collision in the end. SHA-1 is fiercely resisting deprecation, although it is losing out in the end :)
Dec
6
comment Is any group of bits in a SHA-1 hash more/less unique than another?
@mikeazo I guess that kind of remark could be an important part of an answer. But for anybody not directly into attacks on SHA - such as me - it certainly does not answer the question.
Dec
6
comment Is any group of bits in a SHA-1 hash more/less unique than another?
@mikeazo Eh, how do you recon that this is a dupe of that? Are you pointing to the right question?
Dec
6
comment SHA1 Collisions - what about practical attacks?
I've created an answer that basically says: see MD5. In what sense are these the same attacks against MD5? Are there differences?
Dec
3
comment Soundness of GRC.com Haystack padding concept
You cannot keep it secret as Gibson just published the basics :) The choice & number of character does not add enough entropy.
Dec
3
comment Soundness of GRC.com Haystack padding concept
Yes, basically it is not secure if you allow an attacker to explicitly target your password scheme. And since schemes should be considered public knowledge, this method does not provide significant defence. But I don't have enough time right now to put that in mathematical notation.
Dec
3
comment Soundness of GRC.com Haystack padding concept
@pg1989 Gibson is a well known security researcher. That said, he's mostly well known because of his rather non-conforming (and sometimes rather far fetched or idiotic) ideas.
Dec
3
comment Soundness of GRC.com Haystack padding concept
The question looks OK now. That cannot be said about the padding idea of Gibson. But these two remarks are opinionated :)
Dec
3
comment Can a secret message be securely transmitted within a MAC tag?
I agree with ushadm that GCM would not be a good idea if the tag size needs to be shortened.
Dec
3
comment Using the same symmetric key in both directions?
If it was, you wouldn't need the additional encryption (but feel free to shoot yourself in the foot).
Dec
2
comment Collision in Merkle–Damgård without a collision in compression function
@CodesInChaos It would be interesting to know what you make of bilge's answer.
Dec
2
comment Can public key be recovered from chipher text & encrypted private key?
Any progress on this, Dima? Don't forget to follow up on your questions.
Dec
2
comment Verifying DER encoded DSA/ECDSA signature with extra content?
Sorry, have to agree with thera that there is no explicit standard for handling this, it is up to the protocol. So no clear yes/no answer is possible. Beware that you don't make your verification routines (too) generic; different protocols, different choices. Some duplicate code is OK if the protocols are only identical by chance.