| // Copyright 2018 Brian Smith. |
| // |
| // Permission to use, copy, modify, and/or distribute this software for any |
| // purpose with or without fee is hereby granted, provided that the above |
| // copyright notice and this permission notice appear in all copies. |
| // |
| // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES |
| // WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
| // MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY |
| // SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| // WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION |
| // OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN |
| // CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
| |
| use crate::error; |
| use core::convert::TryInto; |
| |
| /// A nonce for a single AEAD opening or sealing operation. |
| /// |
| /// The user must ensure, for a particular key, that each nonce is unique. |
| /// |
| /// `Nonce` intentionally doesn't implement `Clone` to ensure that each one is |
| /// consumed at most once. |
| pub struct Nonce([u8; NONCE_LEN]); |
| |
| impl Nonce { |
| /// Constructs a `Nonce` with the given value, assuming that the value is |
| /// unique for the lifetime of the key it is being used with. |
| /// |
| /// Fails if `value` isn't `NONCE_LEN` bytes long. |
| #[inline] |
| pub fn try_assume_unique_for_key(value: &[u8]) -> Result<Self, error::Unspecified> { |
| let value: &[u8; NONCE_LEN] = value.try_into()?; |
| Ok(Self::assume_unique_for_key(*value)) |
| } |
| |
| /// Constructs a `Nonce` with the given value, assuming that the value is |
| /// unique for the lifetime of the key it is being used with. |
| #[inline] |
| pub fn assume_unique_for_key(value: [u8; NONCE_LEN]) -> Self { |
| Self(value) |
| } |
| } |
| |
| impl AsRef<[u8; NONCE_LEN]> for Nonce { |
| fn as_ref(&self) -> &[u8; NONCE_LEN] { |
| &self.0 |
| } |
| } |
| |
| /// All the AEADs we support use 96-bit nonces. |
| pub const NONCE_LEN: usize = 96 / 8; |