Update documentation for age comparison and .NET version?

[Ganwtrs]

Kryptor's newest release updates to .NET 8, but the documentation says it's on .NET 6. Could the FAQ be updated to reflect this?

Also, Filippo mentions this about Kryptor compared to age,

• sender authentication

I wrote about this. tl;dr age has authentication, but I am not sure what a non-sharp UX around it would be, so I don't advertise it. https://words.filippo.io/dispatches/age-authentication/

• post-quantum security

As https://www.kryptor.co.uk/security-limitations#post-quantum-security acknowledges, "the asymmetric algorithms in Kryptor aren't post-quantum secure". There is support for adding a pre-shared symmetric key, although I did not find the pre-shared key in the usage section, but I would argue that is not asymmetric encryption.

In this sense, I would actually argue that Kryptor is just as post-quantum secure as age: age's symmetric encryption (the passphrase mode) is post-quantum (see https://words.filippo.io/dispatches/post-quantum-age/). We don't support adding a pre-shared symmetric key to asymmetric encryption, but if you have a secure channel to establish a pre-shared key, you should just use passphrase mode.

• private key encryption

age supports that! https://github.com/FiloSottile/age?tab=readme-ov-file#passphrase-protected-key-files

It's not the default because most threat models don't need it: if you have FDE, who's an attacker that can read files from your disk but not replace the age binary in $PATH?

could the website's Features section be updated to address this?

[samuel-lucas6]

Kryptor's newest release updates to .NET 8, but the documentation says it's on .NET 6. Could the FAQ be updated to reflect this?

Thank you for pointing that out. I've fixed that. I previously only updated the Installation page.

I wrote about this. tl;dr age has authentication, but I am not sure what a non-sharp UX around it would be, so I don't advertise it. https://words.filippo.io/dispatches/age-authentication/

I have read that post properly, but it was a long time ago, and I haven't been keeping up with age due to other things happening.

The authentication in age is different to in Kryptor but both are flawed. In Kryptor, your public key doesn't need to be hidden. However, doing sender authentication with multiple recipients and streaming is not trivial. This is already discussed on the Known limitations page, although could be updated with those links in mind.

In this sense, I would actually argue that Kryptor is just as post-quantum secure as age: age's symmetric encryption (the passphrase mode) is post-quantum (see https://words.filippo.io/dispatches/post-quantum-age/). We don't support adding a pre-shared symmetric key to asymmetric encryption, but if you have a secure channel to establish a pre-shared key, you should just use passphrase mode.

That's a fair point, although using a passphrase isn't equivalent to a key exchange with a pre-shared key. If the passphrase is compromised, the file can be decrypted. If the pre-shared key is compromised, you still have classical security. I do personally prefer fully symmetric methods though.

age also uses a 128-bit file key, whereas Kryptor uses a 256-bit key. However, a 128-bit key is still considered post-quantum secure.

age supports that! https://github.com/FiloSottile/age?tab=readme-ov-file#passphrase-protected-key-files

It's not the default because most threat models don't need it: if you have FDE, who's an attacker that can read files from your disk but not replace the age binary in $PATH?

That's worth mentioning. I can't remember if that was always supported, but I think I made this distinction because it wasn't on by default. It basically encourages plaintext keys, unlike Minisign.

The issue with relying on FDE is that only technical people turn that on, you could back up the private key to an external drive without FDE or cloud storage, and your plaintext private key will be compromised if you accidentally share it. Therefore, encrypting the private key gives some additional protection.

could the website's Features section be updated to address this?

I don't think that section is appropriate, but the Goals section should be updated. I'll make a note to do this.

Kryptor and age are really completely different projects. Filippo's full-time job is maintaining open source software, whereas I'm doing it as a hobby/learning exercise. My job has nothing to do with cryptography or software development, and any time I put into these things is time I'm not putting into learning something more relevant to my role. I'm also at one of the busiest times of my life so far and am trying to juggle learning things with maintaining things. Then age has a much larger user base and separate goals, like support for plugins.