Add support for arrayvec in aead

[antonok-edm]

arrayvec is a popular alternative to the heapless crate; it has over 65 million all-time downloads and is used in several high-profile crates.

I've added an arrayvec feature to aead. When enabled, the aead::Buffer trait is implemented for ArrayVec<u8, N>.

Example usage

This usage is modeled off of the heapless example from the aes-gcm-siv crate documentation.

fnmain() -> Result<(),Box<dyn std::error::Error>>{use aes_gcm_siv::{
aead::{AeadInPlace,KeyInit,OsRng, arrayvec::ArrayVec},Aes256GcmSiv,Nonce,// Or `Aes128GcmSiv`};let key = Aes256GcmSiv::generate_key(&mutOsRng);let cipher = Aes256GcmSiv::new(&key);let nonce = Nonce::from_slice(b"unique nonce");// 96-bits; unique per messageletmut buffer:ArrayVec<u8,128> = ArrayVec::new();// Note: buffer needs 16-bytes overhead for auth tag tag
buffer.try_extend_from_slice(b"plaintext message")?;// Encrypt `buffer` in-place, replacing the plaintext contents with ciphertext
cipher.encrypt_in_place(nonce,b"",&mut buffer)?;// `buffer` now contains the message ciphertextassert_ne!(&buffer[..],b"plaintext message");// Decrypt `buffer` in-place, replacing its ciphertext context with the original plaintext
cipher.decrypt_in_place(nonce,b"",&mut buffer)?;assert_eq!(&buffer[..],b"plaintext message");Ok(())}

Until this is merged and aes-gcm-siv is updated with a corresponding arrayvec feature, this would need to be run with a Cargo.toml with the following dependencies/patch:

[dependencies]
aes-gcm-siv = { version = "0.11.1", features = [ "std" ] }
arrayvec = { version = "0.7.2", features = [ "std" ] }
aead = { version = "*", features = [ "arrayvec" ] }
[patch.crates-io]
aead = { path = "/path/to/this/branch/of/traits/aead" }

[tarcieri]

The other dependencies are in alphabetical order

[antonok-edm]

Ah, thanks! Updated.

[tarcieri]

Thanks!

[antonok-edm]

@tarcieri I have a branch ready for a PR in https://github.com/RustCrypto/AEADs; let me know once this makes it to a new release on crates.io and I'll get a PR opened for that too