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location Netherlands
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visits member for 4 years, 1 month
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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.


Jul
4
comment Blinding to mask private key operations
Could/should have been asked on the crypto site...
Jul
2
comment Security protocol for NFC stickers/cards
@AaronD Could you possibly synthesize an answer?
Jul
2
comment Understanding salted password hashing using Java
Yeah, I guess it is better than nothing. Note that there now is a Destroyable interface for keys in Java 8. It may be that there will be some kind of support for destroying key / password data. Currently you cannot reliably implement the FIPS requirements without going native / HW.
Jul
2
comment Using RSA-SHA as/instead HMAC in OpenVPN?
Maybe you should offer a bounty on this. I can only bump it using comments (if I ever want to reach 1K).
Jun
28
answered Machine readable, user non-readable - XML file
Jun
23
comment Getting multiple key matches on plaintext/ciphertext pairs in double DES
No not really. Each bit of the output should depend on each bit in the key. Even if there are a lot of zeros or ones changing one bit should change the ciphertext significantly (indistinguishable from random, so an average hamming distance of half of the block size, 32 bits).
Jun
23
answered Getting multiple key matches on plaintext/ciphertext pairs in double DES
Jun
23
comment Getting multiple key matches on plaintext/ciphertext pairs in double DES
What do you mean with "key pairs" in this question?
Jun
19
comment What are the risks associated with relying on Mutual SSL & IP Filtering?
With mutual SSL I read TLS with client authentication (server authentication is implied). Am I correct in assuming this?
Jun
19
comment How to check randomness of a hash?
If you have enough entropy you can bring back to bits you can check the randomness using either FBI or German BSI randomness validators. But I guess that would "somewhat" of an overkill. It would require a study into randomness just to interpret in the input requirements & the output.
Jun
19
awarded  Enthusiast
Jun
18
awarded  Yearling
Jun
18
comment How to identify hashes
Small side note: sometimes only y bits are used of the full output size of a hash or HMAC. These are also indistinguishable from random (so 160 bits taken from SHA-256 cannot be distinguished from a full SHA-1). So output size in bits in itself may still not give that much of a hint.
Jun
18
comment How to identify hashes
You're welcome. I hope I made the distinction between a cryptographic hash and an encoded hash of a protocol clear enough.
Jun
18
answered How to identify hashes
Jun
17
comment What is the best solution to encrypt pagefile?
PS I'm presuming here that these alternatives are provided by the OS. If not you may want to rethink your strategy. In other words, the above answer is just about the choice of algorithm, nothing else.
Jun
17
answered What is the best solution to encrypt pagefile?
Jun
16
comment Can I convert a public key to a private key?
You should never encrypt with a private key. You can still encrypt with the public key, but that's the equivalent of tossing the bits in the bit bucket, i.e. the ciphertext cannot be reverted into plaintext anymore afterwards.
Jun
16
comment Can I convert a public key to a private key?
"not going to be easy to break" is quite an understatement here.
Jun
16
comment How secure is the “read-only” feature of a passive NFC tags?
I would like to do an informed guess that logically speaking it is easy show that it is read-only afterwards. How well it is protected against perturbation (i.e. active attacks with lasers, Y-beams and such like) is strongly implementation dependent.