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location Netherlands
age 40
visits member for 2 years, 7 months
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Java and security expert with over 10 years of experience with the language and with the practical application of cryptographic protocols - including the design of protocols within international standardization bodies. Creator of a heavily used common criteria certified product. Over 30 years of experience with computers. Likes kids, cats, reading, movies and several sports.


2d
comment Sectors of small data encryption
You really need to study the subject more, Giliweed. Just firing almost random questions to all kinds of sites is not the best method of studying crypto, not to mention that you will annoy lots of people with value basic questions. You may not get the best answers this way either.
2d
revised Predicting PRNG given some of its previous output
added 82 characters in body
2d
revised Process of dividing 168bit key into 56bit keys in TripleDES
formatted according to FIPS 46-3, mentioned TDEA as name, removed links to blogs about language implementations
2d
revised Process of dividing 168bit key into 56bit keys in TripleDES
formatted according to FIPS 46-3, mentioned TDEA as name, removed links to blogs about language implementations
2d
reviewed Close Where can I begin to study the math behind modern cryptography?
Jul
19
answered KDF based on HMAC-SHA-256
Jul
19
comment Modes of operation that allow padding oracle attacks
@D.W. The best definition I can come up with is "any attack that relies on the unpadding of the decrypted plaintext message to retrieve information on the plaintext". If an attacker only has access to the ciphertext - and this presumption may be made - then it would be a subset of chosen ciphertext attacks. BTW I was expecting that this was more or less implied by the question. Obviously the CBC specific attack would not work for any other mode than CBC without some alteration.
Jul
18
comment Is TripleDES 168bit vulnerable to Differential Cryptanalysis?
Source: Wikipedia: "In 1994, a member of the original IBM DES team, Don Coppersmith, published a paper stating that differential cryptanalysis was known to IBM as early as 1974, and that defending against differential cryptanalysis had been a design goal.[2]"
Jul
18
comment Can I crack an AES string if I have all these parameters?
Me neither, and I have tried ECB, CBC, OFB, CFB, CTR, GCM and CCM. I haven't tried all possibilities with regards to OFB and CFB though. Next I'm writing a whole suite for crypto-analysis :P
Jul
18
comment Can I crack an AES string if I have all these parameters?
Did anybody crack this yet? I had a stab at it but I cannot find anything, having tried multiple modes of operation. I don't need the answer, just "yes, I did crack it" or "no, nothing found" would be sufficient.
Jul
18
accepted Modes of operation that allow padding oracle attacks
Jul
18
comment Modes of operation that allow padding oracle attacks
I would count switching the blocks around in ECB a kind of padding oracle attack. An attack does not have to provide full plaintext to be considered successful - it does give information about the plaintext and more than just the length. It depends on the use case if the vulnerability has any significance. Thanks!
Jul
18
comment Is TripleDES 168bit vulnerable to Differential Cryptanalysis?
The question is valid, but if that's a scientific paper then I'm little red riding hood.
Jul
18
comment Modes of operation that allow padding oracle attacks
I'll have a look of course. I just thought that maybe somebody had taken a look before me. Otherwise I'll try and answer myself. Besides, it is a while back that I programmed the padding oracle attack (I used my old implementation for Crypto I at coursera and it worked the first time, so I did not take too good a look).
Jul
18
comment Storing encryption key
If you are very confused about encryption then a password manager may not be the best thing to program, unless it is as a learning experience.
Jul
18
comment Modes of operation that allow padding oracle attacks
I know most of this, and I know about Vaudenays paper. I've actually used it to show padding Oracles on XML encrypt for a specific product. But I don't see anything in it about explicit tests on other modes of operation - except authenticated encryption of course. ECB is in there, but only to explain that CBC is as efficient (same number of block encrypts) as ECB.
Jul
17
comment Modes of operation that allow padding oracle attacks
Thank you, but that's not what I was asking.
Jul
17
asked Modes of operation that allow padding oracle attacks
Jul
16
comment Does CCA security imply authenticated encryption?
Downvoter, please add a comment to downvotes or improve the answer instead.
Jul
16
comment Decrypting an encrypted text out of order
Only problem is that I always get confused with commutative and associative. As addition and xorring are both, I guess it's not harmful in this case.