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I'm an engineer with experience in applied cryptography, in particular in Smart Card systems.


Jul
24
revised What security authorities and standards reject $e=3$ in RSA, when, and with what rationale?
typo
Jul
24
reviewed Close LFSR and Markov chain question
Jul
24
revised What security authorities and standards reject $e=3$ in RSA, when, and with what rationale?
typo
Jul
24
revised What security authorities and standards reject $e=3$ in RSA, when, and with what rationale?
Clearly state my opinion
Jul
24
revised What security authorities and standards reject $e=3$ in RSA, when, and with what rationale?
Include links to RGS and its approval, with corrected date; state main change
Jul
24
revised What security authorities and standards reject $e=3$ in RSA, when, and with what rationale?
Polish
Jul
24
accepted What security authorities and standards reject $e=3$ in RSA, when, and with what rationale?
Jul
24
answered What security authorities and standards reject $e=3$ in RSA, when, and with what rationale?
Jul
24
revised Rainbow table for DES with all-zero plaintext?
Generalization
Jul
24
wiki created rainbow-table description
Jul
24
wiki created rainbow-table excerpt
Jul
24
asked Rainbow table for DES with all-zero plaintext?
Jul
24
comment Reordering non-block-aligned parts with DES in ECB mode
Yes, with the assumption of a known plaintext block common to enough instances of the problem to make a precomputation worthwile, what you are describing is feasible. However that does not apply in the situation of the question: there is no indication of multiple instances, and I see no hope to find an existing rainbow table that applies, for we need a different table for each known plaintext block.
Jul
23
comment Secure way to store fixed size string of digits
Define "securely". $\;$ You want to achieve confidentiality, but what about integrity, and high insurance of availability despite hardware mishaps? $\;$ When you need the data, is it for the purpose of testing if some string is that 9-digit string, or do you need to retrieve that value? $\;$ If you can retrieve that 9-digit string value, and the adversary can't, what can the system use to differentiate you from the adversary? $\;$ What is it reasonable to believe an attacker can/can't do on your system?
Jul
23
comment RSA with modulus n=p²q
@bmm6o: Ah right, I had missed that.
Jul
23
comment Which algorithm do you recommend for practical use to generate unique passwords for each website?
Many sites have password requirements than make the "Turn the site secret into a usable password" step non-trivial, and hard to get right; like (I'm not making that up): At least 15 characters. Contains CAPITAL Letters. Contains SMALL letters. Contains either special characters or numbers (e.g. / , *, @, #, $, or 1, 2, 3 etc.). $\;$ Typically that spec is imprecise, often hard to get or/and existing in different versions, and more often than not wrong (e.g. here, the system actually allows both special characters and numbers, and I'm not even sure that it does not require that).
Jul
23
comment RSA with modulus n=p²q
The potential saving is actually greater than for multiprime RSA with 3 primes, because there are only 2 expensive modexp to perform, rather than 3. On the other hand, the modified CRT is quite a bit unusual.$\;$ Note: To get the paper, a click on "download chapter" on the page you link works for me; and then I can save the PDF (I believe, legally); that's a fortunate consequence of the IACR copyright policy.
Jul
23
comment RSA with modulus n=p²q
@Ricky Demer: I fail to see why the restriction to coprime $j$ and $k$. $\;$ That $\gcd$ trick is nice!
Jul
23
revised RSA with modulus n=p²q
Slightly restructure; give standard e.
Jul
23
revised RSA with modulus n=p²q
Fix a formula which was suboptimal (though only when the RNG is hopelessly broken)