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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.


Mar
27
comment Using the Vigenere Cipher to find key
The second part of your description reads like a method of breaking a one time pad (what sub-keys are you referring to?).
Mar
27
comment Key sizes supported by 3DES
Do you have a reference to a product that specifies 256 bit triple DES? It's nice to have a good laugh from time to time :)
Mar
27
revised Key sizes supported by 3DES
added some additional terms and explained about 112/168 bit keys
Mar
27
comment Key sizes supported by 3DES
If I remember correctly the idea that 3DES would emulate DES when used with a single 64 bit key for key 1, 2 and 3 (or key A, B and C if I remember the specs correctly) was meant as specific property of 3DES as you could use the same circuitry to accomplish both.
Mar
27
comment Practical brute-force attack on 128 bit encryption
Because KeySpace/2 is the average amount of tries required?
Mar
27
comment Practical brute-force attack on 128 bit encryption
Amended answer, including a pointer to the 72 bit key space search.
Mar
27
revised Practical brute-force attack on 128 bit encryption
added 574 characters in body
Mar
27
revised Practical brute-force attack on 128 bit encryption
added 55 characters in body
Mar
27
answered Practical brute-force attack on 128 bit encryption
Mar
26
comment Encode-decode with different block sizes?
You're welcome to post this on StackOverflow, but in that case please include the source code (as a self contained example).
Mar
26
comment Can machine learning analyze random number generator?
It's good background info, I'm not sure if it qualifies as an answer. AES-CTR is close but not quite a CSPRNG I guess, it does not offer re-seed possibilities for instance.
Mar
26
comment Can machine learning analyze random number generator?
I'm pretty sure those tests are not considered "machine learning".
Mar
26
comment AES or Serpent-Twofish-AES
No it shouldn't.
Mar
26
comment AES or Serpent-Twofish-AES
I can flag your post if you don't stop that highlighting BS.
Mar
26
revised AES or Serpent-Twofish-AES
rolled back to a previous revision
Mar
26
revised AES or Serpent-Twofish-AES
deleted 19 characters in body
Mar
25
comment Are modes of operation algorithms practical?
Note that there is a difference between the mode of operation and the block cipher itself. Both are needed for a general encryption algorithm of course and both should adhere to Kerckhoff's principle. If you want to encrypt on the front office side / decrypt on the back office side you may consider asymmetric encryption. Certainly take a look at what's already out there.
Mar
24
comment Is it safe to use PBEWithMD5AndDES?
No, the current record seems to be around one day, and that with specialized hardware. Ciphers with very low key sizes can therefore be used for realtime protocols. I would not be surprised if the NSA can crack DES in minutes. But do not know any more than the Wikipedia page on DES.
Mar
23
comment Credit card number encryption using AES counter mode
I'm certainly going to give this question all the attention that the author puts in it.
Mar
23
reviewed Approve Credit card number encryption using AES counter mode