Struct aes_gcm::AesGcm

pub struct AesGcm<Aes, NonceSize, TagSize = U16>
where
    TagSize: TagSize,
{
    pub(crate) cipher: Aes,
    pub(crate) ghash: GHash,
    pub(crate) nonce_size: PhantomData<NonceSize>,
    pub(crate) tag_size: PhantomData<TagSize>,
}

AES-GCM: generic over an underlying AES implementation and nonce size.

This type is generic to support substituting alternative AES implementations (e.g. embedded hardware implementations)

It is NOT intended to be instantiated with any block cipher besides AES! Doing so runs the risk of unintended cryptographic properties!

The NonceSize generic parameter can be used to instantiate AES-GCM with other nonce sizes, however it’s recommended to use it with typenum::U12, the default of 96-bits.

The TagSize generic parameter can be used to instantiate AES-GCM with other authorization tag sizes, however it’s recommended to use it with typenum::U16, the default of 128-bits.

If in doubt, use the built-in Aes128Gcm and Aes256Gcm type aliases.

Fields

cipher: Aes

Encryption cipher.

ghash: GHash

GHASH authenticator.

nonce_size: PhantomData<NonceSize>

Length of the nonce.

tag_size: PhantomData<TagSize>

Length of the tag.

Implementations

impl<Aes, NonceSize, TagSize> AesGcm<Aes, NonceSize, TagSize>

where Aes: BlockCipher + BlockSizeUser<BlockSize = U16> + BlockEncrypt, NonceSize: ArrayLength<u8>, TagSize: TagSize,

pub(crate) fn init_ctr( &self, nonce: &Nonce<NonceSize>, ) -> (CtrCore<&Aes, Ctr32BE>, GenericArray<u8, U16>)

Initialize counter mode.

See algorithm described in Section 7.2 of NIST SP800-38D: https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-38d.pdf

Define a block, J0, as follows: If len(IV)=96, then J0 = IV || 0{31} || 1. If len(IV) ≠ 96, then let s = 128 ⎡len(IV)/128⎤-len(IV), and J0=GHASH(IV||0s+64||[len(IV)]64).

pub(crate) fn compute_tag( &self, mask: GenericArray<u8, U16>, associated_data: &[u8], buffer: &[u8], ) -> Tag

Authenticate the given plaintext and associated data using GHASH.

Trait Implementations

impl<Aes, NonceSize, TagSize> AeadCore for AesGcm<Aes, NonceSize, TagSize>

where NonceSize: ArrayLength<u8>, TagSize: TagSize,

type NonceSize = NonceSize

The length of a nonce.

type TagSize = TagSize

The maximum length of the nonce.

type CiphertextOverhead = UTerm

The upper bound amount of additional space required to support a ciphertext vs. a plaintext.

fn generate_nonce( rng: impl CryptoRng + RngCore, ) -> GenericArray<u8, Self::NonceSize>

where GenericArray<u8, Self::NonceSize>: Default,

Generate a random nonce for this AEAD algorithm.

impl<Aes, NonceSize, TagSize> AeadInPlace for AesGcm<Aes, NonceSize, TagSize>

where Aes: BlockCipher + BlockSizeUser<BlockSize = U16> + BlockEncrypt, NonceSize: ArrayLength<u8>, TagSize: TagSize,

fn encrypt_in_place_detached( &self, nonce: &Nonce<NonceSize>, associated_data: &[u8], buffer: &mut [u8], ) -> Result<Tag<TagSize>, Error>

Encrypt the data in-place, returning the authentication tag

fn decrypt_in_place_detached( &self, nonce: &Nonce<NonceSize>, associated_data: &[u8], buffer: &mut [u8], tag: &Tag<TagSize>, ) -> Result<(), Error>

Decrypt the message in-place, returning an error in the event the provided authentication tag does not match the given ciphertext (i.e. ciphertext is modified/unauthentic)

fn encrypt_in_place( &self, nonce: &GenericArray<u8, Self::NonceSize>, associated_data: &[u8], buffer: &mut dyn Buffer, ) -> Result<(), Error>

Encrypt the given buffer containing a plaintext message in-place.

fn decrypt_in_place( &self, nonce: &GenericArray<u8, Self::NonceSize>, associated_data: &[u8], buffer: &mut dyn Buffer, ) -> Result<(), Error>

Decrypt the message in-place, returning an error in the event the provided authentication tag does not match the given ciphertext.

impl<Aes: Clone, NonceSize: Clone, TagSize> Clone for AesGcm<Aes, NonceSize, TagSize>

where TagSize: TagSize + Clone,

fn clone(&self) -> AesGcm<Aes, NonceSize, TagSize>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<Aes, NonceSize, TagSize> From<Aes> for AesGcm<Aes, NonceSize, TagSize>

where Aes: BlockSizeUser<BlockSize = U16> + BlockEncrypt, TagSize: TagSize,

fn from(cipher: Aes) -> Self

Converts to this type from the input type.

impl<Aes, NonceSize, TagSize> KeyInit for AesGcm<Aes, NonceSize, TagSize>

where Aes: BlockSizeUser<BlockSize = U16> + BlockEncrypt + KeyInit, TagSize: TagSize,

fn new(key: &Key<Self>) -> Self

Create new value from fixed size key.

fn new_from_slice(key: &[u8]) -> Result<Self, InvalidLength>

Create new value from variable size key.

fn generate_key( rng: impl CryptoRng + RngCore, ) -> GenericArray<u8, Self::KeySize>

Generate random key using the provided CryptoRng.

impl<Aes, NonceSize, TagSize> KeySizeUser for AesGcm<Aes, NonceSize, TagSize>

where Aes: KeySizeUser, TagSize: TagSize,

type KeySize = <Aes as KeySizeUser>::KeySize

Key size in bytes.

fn key_size() -> usize

Return key size in bytes.