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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.


1h
revised How could honeypot be vulnerable?
fixed list
1h
suggested approved edit on How could honeypot be vulnerable?
2d
comment Understanding Certificate Pinning
@NeilSmithline The reason I left it out is that it could be decryption or signature generation (and actually that seems to be the general direction of TLS for instance). Heck it could be key agreement as well for static (EC)DH keys.
2d
comment Understanding Certificate Pinning
@raz I'm not sure, that question and answers doesn't address the private key / authentication part.
2d
answered Understanding Certificate Pinning
Apr
20
answered Is is possible to avoid internal seeding of a RNG and seed the generator manually using OpenSSL's RAND_bytes()?
Apr
17
comment Asymmetric vs Symmetric Encryption Benchmarks
@Mark ah yes, didn't see the comment. Anyway, one 2048 bit operation would be 245 bytes if PKCS#1 v1.5 padding is applied, less (around 200 bytes if I'm not mistaken) for OAEP-MGF1-SHA1.
Apr
17
comment Evaluating the Entropy of the PRNG in OpenSSL
If not a dupe, the question seems fine.
Apr
17
comment Asymmetric vs Symmetric Encryption Benchmarks
The T1/T2 range of processors do actually have a asymmetric coprocessor, but otherwise I've only seen them in security related products. Most of the time Elliptic Curve encryption uses an encryption scheme based on Diffie-Hellman, which means it already has to use hybrid cryptography.
Apr
17
answered Asymmetric vs Symmetric Encryption Benchmarks
Apr
13
comment “&” character in url
Shouldn't that be NothingHappend!= instead of &NothingHappend!=?
Apr
13
comment Do I need to set maximum characters length for password using bcrypt?
Or: "72 characters is the same size as this sentence; don't worry about it :)"
Apr
13
comment More secure curve than Curve25519
As for your last remark: that's not so strange, the 256 bit cipher will have almost no overhead (both with regards to size and CPU power). Calculating a >4K RSA key is tricky, the HSM's will be expensive. So although 256 bit AES will not provide much of a security benefit, it won't hurt much either. I'm mostly against AES-256 because it makes a protocol look more secure than it actually is - most of the time. E.g clients wanting 256 bit AES on a smart card where side channel attacks are a much bigger threat; they are basically fooling themselves.
Apr
13
comment More secure curve than Curve25519
I guess it depends on how well you test the parameters and how much you trust the organizations, but there are the P521 and Brainpool P512 curves. Although Bernstein shows very well how using these curves can be dangerous, that doesn't mean that they are certain to have a lower security level than about half the number of bits.
Apr
8
comment How are symmetric cryptographic keys stored?
SRP establishes session keys. Session keys are regenerated for each session; usually you don't store session keys anywhere except in RAM. You could of course store them in a secure container (token device such as a HSM or smart card) but usually it doesn't make sense to store it at a location more secure than the data (authentication state) it is trying to protect.
Apr
8
awarded  Organizer
Apr
8
revised Which parameters can I use to analyse my cipher?
title mainly, some formatting, removed "now", additional tags
Apr
8
suggested approved edit on Which parameters can I use to analyse my cipher?
Apr
8
comment Which parameters can I use to analyse my cipher?
ASCII conversion is usually not considered part of a modern cipher (unless is it explicitly made for human consumption). Modern ciphers convert octet strings (binary data) to octet strings. The conversion to and from the octet string is not considered part of the cipher.
Apr
3
comment Generating secret keys with secret keys
A KBKDF is a Key Based Key Derivation Function. It does what you are trying to achieve with the HMAC. I'm not saying that the HMAC construction is not secure, but KBKDF's have been specifically designed to perform key derivation. The most modern one is arguably HKDF. It's also based on a HMAC.