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Sep
18
answered What is the post-quantum cryptography alternative to Diffie-Hellman?
Sep
10
comment SHA1 usage for passwords, alternatives and advantages?
@Niklas R: Please read the comments and the links and try to read things a bit more carefully. Your comments are pretty much all over the place. crypt is not only DES and you are mixing up the hash algorithm with the "operating mode". PBKDF2 may use SHA1 internally and it is as secure as any. The point is not to use simple concatenation of salt and password hashed, but something more complex - the point is not to change the actual hash function used.
Sep
8
comment Does NTRU decrypt correctly now?
Just to make it even more obvious: those parameters have been chosen for a $2^{256}$ security level in general, and the failure probability is also smaller than $2^{-256}$. So exploiting a decryption failure requires just as much work as breaking other parts of the system.
Sep
5
comment SHA1 usage for passwords, alternatives and advantages?
The very very very old DES crypt was vulnerable to just about everything and ignores everything after the first 8 characters. The crypt(3) in modern Linuxes uses SHA-256, has no password length limits, has a configurable amount of rounds just like PBKDF2, uses a 16 character salt, etc. The same function on OpenBSD is bcrypt. crypt(3) is just an interface.
Sep
5
comment SHA1 usage for passwords, alternatives and advantages?
If it wasn't obvious, import crypt in Python is just a wrapper for the crypt(3) function in the underlying platform - and as such, behaves differently on different UNIX systems.
Sep
5
comment SHA1 usage for passwords, alternatives and advantages?
Actually, using crypt(3) doesn't actually fix the algorithm to anything specific - there are many different implementations of the UNIX crypt and some of them provide really weak security. Please see more at: en.wikipedia.org/wiki/Crypt_(Unix) and manpages.courier-mta.org/htmlman3/crypt.3.html Also, for example the SHA-256 and SHA-512 algorithms for crypt(3) are really weird: akkadia.org/drepper/SHA-crypt.txt I'm not sure if I can recommend those fully.
Sep
5
comment Does NTRU decrypt correctly now?
Found a paper saying mostly what I said: "Furthermore, note that the sender cannot test if the decryption will fail or not, since the private key f is required.": homes.esat.kuleuven.be/~fvercaut/papers/cc03.pdf
Sep
5
revised SHA1 usage for passwords, alternatives and advantages?
Added links.
Sep
5
comment Does NTRU decrypt correctly now?
I really don't know the specifics, but if I remember right the problem was that a "random" parameter selected by the encrypter may make the decryption process fail - and it is impossible for the encrypter to verify if this is the case without the private key. Maybe! Please confirm my understanding.
Sep
5
answered SHA1 usage for passwords, alternatives and advantages?
Sep
1
comment What is the post-quantum cryptography alternative to Diffie-Hellman?
I accepted this answer because it contained more information that I didn't already know.
Sep
1
accepted What is the post-quantum cryptography alternative to Diffie-Hellman?
Aug
31
comment What is the signature scheme with the fastest batch verification protocol for multiple signers?
On eBASH, ronald3072 is RSA at 3072 bits (roughly the same security level). It seems to be verifying signatures at 178592 cycles per verification (non-batched), which is faster than ed25519 without batching, but not with. I am not debating that Rabin-Williams can be made to provide faster verification than ed25519, I just am not aware of any concrete implementations that do. Also, if the security level can be less than exactly 2<sup>128</sup>, RSA will get significantly faster compared to the alternatives.
Aug
30
revised What is the signature scheme with the fastest batch verification protocol for multiple signers?
fix typo
Aug
30
answered What is the signature scheme with the fastest batch verification protocol for multiple signers?
Aug
28
revised Looking for cryptographic secure hash algorithm(s) that produces identical root hash for differently sliced hash list
added 155 characters in body; added 22 characters in body
Aug
28
answered Looking for cryptographic secure hash algorithm(s) that produces identical root hash for differently sliced hash list
Aug
25
revised What is the post-quantum cryptography alternative to Diffie-Hellman?
Clarified the public key encryption key agreement part to help getting relevant answers.
Aug
25
awarded  Commentator
Aug
25
comment What is the post-quantum cryptography alternative to Diffie-Hellman?
The RFC draft was very interesting, thank you for the link!