Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Add Support for calling libsodium crypto_aead_aes256gcm_encrypt_detached and crypto_aead_aes256gcm_decrypt_detached #84

Open
JpGallegos opened this issue Jul 31, 2024 · 5 comments · May be fixed by #85
Open

Add Support for calling libsodium crypto_aead_aes256gcm_encrypt_detached and crypto_aead_aes256gcm_decrypt_detached #84

JpGallegos opened this issue Jul 31, 2024 · 5 comments · May be fixed by #85

Comments

@JpGallegos
Copy link

JpGallegos commented Jul 31, 2024 •
edited
Loading

Description

I would like to request the addition of support for calling the crypto_aead_aes256gcm_encrypt_detached and crypto_aead_aes256gcm_decrypt_detached functions from the libsodium library.

Proposed API

The proposed API could look similar to existing AEAD functions in the Nsec library, but with additional parameters for handling the detached tag. For example:

public void EncryptDetached(
    Key key,
    ReadOnlySpan<byte> nonce,
    ReadOnlySpan<byte> associatedData,
    ReadOnlySpan<byte> plaintext,
    Span<byte> ciphertext,
    Span<byte> tag);

public bool DecryptDetached(
    Key key,
    ReadOnlySpan<byte> nonce,
    ReadOnlySpan<byte> associatedData,
    ReadOnlySpan<byte> ciphertext,
    ReadOnlySpan<byte> tag,
    Span<byte> plaintext);
@JpGallegos JpGallegos linked a pull request Aug 6, 2024 that will close this issue
Open
@samuel-lucas6
Copy link

May I ask what use case is this for? Are you forced to prepend the tag?

@JpGallegos
Copy link
Author

We're working with code that handles the ciphertext and tag separately to encrypt/decrypt real time communication packets. Processing the output of the combined AES-256-GCM methods to work with the codebase adds undesired latency.

@samuel-lucas6
Copy link

We're working with code that handles the ciphertext and tag separately to encrypt/decrypt real time communication packets. Processing the output of the combined AES-256-GCM methods to work with the codebase adds undesired latency.

Thanks for your reply. In what way? You can't decrypt without verifying the tag. The combined API shouldn't be a problem.

@JpGallegos
Copy link
Author

Can't go into much detail, but, basically, the packets are encrypted and decrypted a few times in different places. Some of those places have libraries that work with the ciphertext and tags in different buffers (detached mode); we could take the combined output and separate them into different buffers, but that adds overhead which can be completely eliminated by just using the detached methods.

@samuel-lucas6
Copy link

Can't go into much detail, but, basically, the packets are encrypted and decrypted a few times in different places. Some of those places have libraries that work with the ciphertext and tags in different buffers (detached mode); we could take the combined output and separate them into different buffers, but that adds overhead which can be completely eliminated by just using the detached methods.

Ah ok. I'm guessing you can't use spans or this is interacting with something in another programming language.

The trouble is the detached API is basically duplicate functionality. If I was designing a library and worried about this problem, I would just expose a detached API, which is what the .NET AES-GCM does. However, the tag is typically appended, so the combined API generally seems preferable and less confusing to the user.

Your PR also only covers AES-GCM, which would make the API inconsistent with the other AEAD schemes. However, I recommend waiting for ektrah to reply before adding anything else. I expect he's busy with work.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Assignees
No one assigned
Labels
None yet
Projects
None yet
Milestone
No milestone
Development

Successfully merging a pull request may close this issue.

Adds support for calls to Libsodium AES-256-GCM detached encrypt/decrypt JpGallegos/nsec
2 participants
@JpGallegos @samuel-lucas6