Add non-cryptographic hashing features such as xxhash and blake3 for cryptographic

[kikyps]

Add a super fast Hashing feature for non-cryptography using the algorithm from xxhash
and is there any idea to upgrade blake2b to latest and faster blake3?

thank you very much for your hard work

[jedisct1]

This is a crypto library, so no, there are no plans to add non-cryptographic hash functions.
For a non-cryptographic hash, take a look at polymur hash.

BLAKE3 has a smaller security margin than BLAKE2, and is hostile to implementers and CPU caches. TurboSHAKE/KangarooTwelve are better alternatives, and are more likely to be added as XOFs. They are about as fast, much cleaner, and are being standardized.

If you have a secret key, need something super fast and only need a 256 bit output, you can use crypto_aead_aegis128l() today.

[jedisct1]

Depends on who is creating the files and who will verify them. Is it the same application?

crypto_generichash() will still be BLAKE2.

[kikyps]

No I just want to do a file check inside my application to detect tampering.

Is there a way to protect openat from hooking/intercepting, which can hook or intercept the openat path by changing the original path to a specified path, can the sodium_mprotect and sodium_mlock functions handle this case to protect the memory area so that openat cannot be hooked so that it always leads to the original path, maybe in the future there will be sodium_openat for this case? XD

I am interested in the new features in the last update, I will learn more about AEADs.

[jedisct1]

If this is inside your own application, you'd better use a MAC, not a hash function (i.e. use a secret key).

Create a 16 bytes secret key with crypto_aead_aegis128l_keygen(), and then use crypto_aead_aegis128l_encrypt_detached(NULL, mac, NULL, NULL, 0, file_content, file_length, NULL, nonce, key).

Note that this doesn't encrypt anything, but it authenticates file_content (which is the associated data).

You'd get a 32 byte authenticator in mac.

The nonce can be set to all zeros, or to 16 arbitrary bytes that represent your application or identifies the file.

That's the fastest option.

[kikyps]

How does it work?
does it work anyway comparing mac with expected mac?
is there a complete documentation reference about this function?
this is very interesting.

Thanks

[jedisct1]

https://doc.libsodium.org/secret-key_cryptography/aead/aegis-128l

Just fill the additional data, keep the message empty.

But first check if generichash is really not fast enough. For the vast majority of application, it likely is.