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21142
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location Netherlands
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visits member for 3 years, 4 months
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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.


8h
comment Stacked LFSR - why not used?
I think LFSR's are primarily used on constrained environments, so requiring a very large state (and at least 1.25 times the processing power) is quite a big thing to ask.
8h
answered Assemble RSA keys from components
9h
comment Assemble RSA keys from components
I've got the strong feeling that this is still at the wrong place. It should include runtime etc. and be asked at StackOverflow.
21h
awarded  Enlightened
22h
awarded  Nice Answer
1d
comment How efficient is the error correcting code?
Comes to that, what do you mean with efficient? Efficient compared to order, CPU time, output size, cryptographic strength, size of the acronym?
1d
revised Practical brute-force attack on 128 bit encryption
added 215 characters in body
1d
comment Collision attacks on digital signatures
See section 5.3: Constructing colliding certificates of "MD5 considered harmful today - Creating a rogue CA certificate"
1d
revised Key sizes supported by 3DES
added 324 characters in body
1d
comment Key sizes supported by 3DES
I guess I can agree on that. The keys should be indistinguishable from random for ciphers, so as long as that pre-condition is taken into account DES AAA is not triple DES. To be completely fair a check should be really present to check that situation though, otherwise the name of the algorithm would depend on the input, which is kind of weird. Or we could just stop using the frickin' 3DES algorithm of course ;)
1d
revised Using the Vigenere Cipher to find key
added 169 characters in body
1d
answered Using the Vigenere Cipher to find key
1d
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?).
1d
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 :)
1d
revised Key sizes supported by 3DES
added some additional terms and explained about 112/168 bit keys
1d
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.
1d
comment Practical brute-force attack on 128 bit encryption
Because KeySpace/2 is the average amount of tries required?
1d
comment Practical brute-force attack on 128 bit encryption
Amended answer, including a pointer to the 72 bit key space search.
1d
revised Practical brute-force attack on 128 bit encryption
added 574 characters in body
1d
revised Practical brute-force attack on 128 bit encryption
added 55 characters in body