Struct seekable_stream_cipher::ascon::StreamCipher

pub struct StreamCipher { /* private fields */ }

An ASCON-based seekable stream cipher.

Implementations

impl StreamCipher

pub const KEY_LENGTH: usize = 32usize

The key length in bytes

pub fn new(key: &[u8; 32], context: impl AsRef<[u8]>) -> Self

Create a new state with the given key and context.

The key must be 32 bytes long, and must be randomly generated, for example using rand::thread_rng().gen::<[u8; 32]>() or getrandom::getrandom().

The context is optional can be of any length. It is used to improve multi-user security.

pub fn fill( &self, out: &mut [u8], start_offset: u64, ) -> Result<(), &'static str>

Fill the given buffer with the keystream starting at the given offset.

The offset is in bytes.

The key stream is deterministic: the same key, context and offset will always produce the same output.

pub fn apply_keystream( &self, out: &mut [u8], start_offset: u64, ) -> Result<(), &'static str>

Encrypt or decrypt the given buffer in place, given the offset.

The buffer is modified in place. The offset is in bytes.

The key stream is deterministic: the same key, context and offset will always produce the same output. This function is equivalent to calling fill and then XORing the output with the input.

Caveats

• There is no integrity.
• An adversary can flip arbitrary bits in the ciphertext and the corresponding bits in the plaintext will be flipped when decrypted.

Trait Implementations

impl Clone for StreamCipher

fn clone(&self) -> StreamCipher

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Copy for StreamCipher