830 reputation
426
bio website en.wikipedia.org/wiki/…
location United Kingdom
age 27
visits member for 3 years, 4 months
seen Mar 20 at 10:34

Pentester, ex-developer, security researcher, reverse engineer, electronics tinkerer, internet activist, zombie eradicator, promulgator of useless facts, shrubbery inspector, bacon aficionado.

Strengths: Security, Crypto, Win32 API, C#, .NET, PHP, x86 assembly

All answers and comments are encrypted with ROT256-ECB.

Opinions are my own. Advice provided with no warranty.


Mar
27
comment Potential vulnerability in DH key selection - am I understanding this right?
Figured as much. In this case I'm trying to break the system rather than fix it (that's someone else's job!) so I guess this definitely counts as a vulnerability.
Mar
27
asked Potential vulnerability in DH key selection - am I understanding this right?
Mar
26
comment Is it feasible to break Diffie-Hellman key exchange when the implementation uses a poor-quality PRNG?
Correction: the seed was the system time in milliseconds on Java 1.4.2 and earlier.
Mar
26
comment Is it feasible to break Diffie-Hellman key exchange when the implementation uses a poor-quality PRNG?
@HenrickHellström According to the docs, it looks like the setSeed method (as called by the constructor) uses all 48 bits. However, the default seed in pre-Java7 is simply the current time as a millisecond-resolution value.
Mar
26
accepted What cipher mode is suitable for independantly decryptable short messages?
Mar
26
accepted Simple homomorphic crypto for 32-bit integers
Mar
26
asked Is it feasible to break Diffie-Hellman key exchange when the implementation uses a poor-quality PRNG?
Jan
19
accepted Is it possible to break a hash-based block cipher?
Jan
10
comment Is it possible to break a hash-based block cipher?
@SamuelNeves Perhaps my nomenclature is off a little. However, wouldn't introduction of a CBC-like mode of operation preclude it being a stream cipher? Granted it's not strictly in either category. Regardless, the question stands as-is.
Jan
10
comment Is it possible to break a hash-based block cipher?
@Thomas Hence my choice of CBC.
Jan
10
asked Is it possible to break a hash-based block cipher?
Jan
6
asked Simple homomorphic crypto for 32-bit integers
Dec
20
comment Why is it important that phi(n) is kept a secret, in RSA?
This is excellent. Very well done.
Nov
29
comment What cipher mode is suitable for independantly decryptable short messages?
@IlmariKaronen Ah, that makes sense. I was erroneously considering each packet as a block.
Nov
29
comment What cipher mode is suitable for independantly decryptable short messages?
@IlmariKaronen Hmmm, is there a reason why Wikipedia describes CBC as using the previous ciphertext block? I can see that a single unique IV should be used for the conversation (i.e. the full stream of blocks), but not per-block.
Nov
29
comment What cipher mode is suitable for independantly decryptable short messages?
@CodesInChaos I'm aware, though the compressed data is a constant size per packet. I think the packets-vs-time domain is where side channel leaks are likely to occur, which I'll have to research further in order to discover a solution.
Nov
29
comment What cipher mode is suitable for independantly decryptable short messages?
Won't CBC require the previous ciphertext block, therefore making one lost packet destroy the next?
Nov
29
comment What cipher mode is suitable for independantly decryptable short messages?
CTR looks like it could do the job. Yes, integrity will be required. I was thinking of using a MAC, but if you know of a better solution I'm all ears! :)
Nov
28
accepted Memory-hard operations in work-factor hash functions
Nov
28
accepted Is it possible to ensure security with zero pre-shared information?