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location Netherlands
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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.


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.
Jul
16
revised Decrypting an encrypted text out of order
edited body
Jul
16
comment Decrypting an encrypted text out of order
Yes, RC4 could be used. But it shouldn't be used anymore. Use e.g. Salsa20 if you really want to use a stream cipher. BF-CTR is Blowfish yes, and will work; any block cipher in CTR mode will work.
Jul
16
answered Is it safe to reuse ECDH asymmetric keys for authentication?
Jul
16
comment How does AES-CCM work in BitLocker?
Don't you understand CCM in BitLocker, or don't you understand CCM at all? Explain CCM is a bit broad.
Jul
16
comment Decrypting an encrypted text out of order
Other stream ciphers will work as well of course.
Jul
16
revised Decrypting an encrypted text out of order
forgot one "commutative" -> associative. I'm used to the Dutch definitions :)
Jul
16
revised Decrypting an encrypted text out of order
forgot one "commutative" -> associative. I'm used to the Dutch definitions :)
Jul
15
comment Decrypting an encrypted text out of order
Welcome to crypto, Osmium.
Jul
15
answered Decrypting an encrypted text out of order
Jul
15
comment Decryption issue with self-coded AES-128
@mikeazo Not that much a problem if you create separate methods for doing the shifting (e.g. using >>> operator). You can always inline them later on using refactoring support of one of the major IDE's. I did not have that much of a problem implementing threefish anyway. That said, I've been doing bit operations for a very long time.