Post by @hipsterelectron@circumstances.run

@hipsterelectron@circumstances.run yesterday

i still don't get why people use elliptic curves instead of diffie-hellman since you can use it for public keys too. the index calculus cryptanalytic method appears to apply for the usage of F_q where q = pn for some prime p. it appears that if q is a large prime and q - 1 is divisible by a large prime, that covers the two biggest error cases

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d@nny disc@

@hipsterelectron@circumstances.run 21 hr. ago

i'm fucking amazed nobody has ever brought up the idea that checksums might be different for the purpose of integrity checking vs cryptographic signatures

d@nny disc@

@hipsterelectron@circumstances.run 21 hr. ago

Richard Hamming, the inventor of Hamming codes,

sure buddy

d@nny disc@

@hipsterelectron@circumstances.run 21 hr. ago

there's a kind of BE NOT AFRAID response i get when considering how to provide checksum trees for a whole file and then all the way up the directory hierarchy.

like you need to have parity data not just for your data but also for your parity data. so you're constructing a parity tree for your parity tree recursively

d@nny disc@

@hipsterelectron@circumstances.run 21 hr. ago

omg usenet again has the innovations in information theory https://en.wikipedia.org/wiki/Parchive

Parchive - Wikipedia

d@nny disc@

@hipsterelectron@circumstances.run 21 hr. ago

parchive volume 3 spec https://parchive.github.io/doc/Parity_Volume_Set_Specification_v3.0.html this looks sick as hell

https://parchive.github.io/doc/Parity_Volume_Set_Specification_v3.0.html

d@nny disc@

@hipsterelectron@circumstances.run 21 hr. ago

this is the sickest shit ever!!!!!

An incremental backup only makes sense when the new set of input files has a lot of overlap with the previous set of input files.

d@nny disc@

@hipsterelectron@circumstances.run 21 hr. ago

An example of using Par-inside is with the ZIP file format.

YES!!!!!!!!!

d@nny disc@

@hipsterelectron@circumstances.run 21 hr. ago

Unfortunately there is not a standard license for file formats.

d@nny disc@

@hipsterelectron@circumstances.run 20 hr. ago

so i don't exactly get the point of disk encryption. it seems to actively avoid the ability to specify application-specific cryptographic keys while enabling a whole host of attacks by virtue of occurring implicitly through the file system

John-Mark Gurney

@encthenet@flyovercountry.social 15 hr. ago

@hipsterelectron
So the problem is most app devs don't have a clue about cryptography, so expecting them to get all the crypto stuff correct isn't really realistic.

And you are correct that full disk encryption protects against evil maid attacks or stolen disk attacks.

Heck, even ceph recently failed to implement cryptography properly. And it is likely reviewed more than more apps will.

P.s. I made FreeBSD's geli, full disk encryption performent.

d@nny disc@

@hipsterelectron@circumstances.run 13 hr. ago

@encthenet if app devs are writing cryptographic code, then i do expect them to get the crypto stuff correct. i also find it incredibly difficult and that's why i've been working through this field for the past several months.

any file that's encrypted at the application level will also protect against the same attacks, so i'm not terribly sure what disk encryption gives you except making everything significantly more difficult to do right. anything in the kernel is going to be significantly more costly to upgrade and fix and that absolutely seems like the wrong place to do encryption

d@nny disc@

@hipsterelectron@circumstances.run 13 hr. ago

@encthenet the alternative is to develop libraries making it easy for application developers to do it right. i was very surprised to find that the libraries out there are largely either djbware or openssl, neither of which are remotely appropriate nor secure

d@nny disc@

@hipsterelectron@circumstances.run 13 hr. ago

@encthenet i would like to learn more about disk encryption. i'm currently working on a novel form of integrity for directory trees through checksum graphs for packaging/build processes/version control and it seems very difficult to me to do encryption at the same level whereas application-layer encryption would compose very well. i think these primitives all need to be done better

John-Mark Gurney

@encthenet@flyovercountry.social 9 hr. ago

@hipsterelectron
You'll actually find soon that doing the symmetric part is easy. The hard part is key management including key rotation.

What do you do when the key to your data leaks? How do you rotate it? How do you make sure that data encrypted with the old key is deleted?

The recent ceph issue was partly they hadn't put together a plan on how to have users migrate to a new encryption scheme.

And having been around, encryption agility (switching ciphers) sounds great and is fine if your just interoperating with yourself, but throw in another implementation, and things get a lot more painful when you can't control which bad ciphers they choose to implement (see TLS cipher defaults in most web servers were [are?] terrible).

Rod Van Meter

@rdviii@famichiki.jp 19 hr. ago

@hipsterelectron DH and RSA are the canonical examples of vulnerable to factoring or discrete logarithm breakthroughs and surprise, that's exactly what Shor's algorithm does.

d@nny disc@

@hipsterelectron@circumstances.run 18 hr. ago

@rdviii shor's algorithm, the one that works on a quantum computer, which will never exist

d@nny disc@

@hipsterelectron@circumstances.run 18 hr. ago

@rdviii it has never once been proven that the claimed mathematical framework assigned to a quantum computer is actually physically realizable

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