spongefish 0.6.1

An implementation of the Fiat--Shamir transformation from Duplex Sponges.
Documentation 
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#[cfg(feature = "ascon")]
pub use ascon::Ascon12;
#[cfg(feature = "keccak")]
pub use keccak::KeccakF1600;

#[cfg(feature = "ascon")]
mod ascon {

    #[derive(Clone, Debug)]
    pub struct Ascon12;
    use crate::duplex_sponge::Permutation;

    impl Permutation<40> for Ascon12 {
        type U = u8;

        fn permute(&self, state: &[u8; 40]) -> [u8; 40] {
            let mut state = ascon::State::from(state);
            state.permute_12();
            state.as_bytes()
        }
    }
}

#[cfg(feature = "keccak")]
mod keccak {
    use core::{fmt::Debug, ptr};

    use crate::duplex_sponge::Permutation;

    /// Keccak permutation internal state: 25 64-bit words,
    /// or equivalently 200 bytes in little-endian order.
    #[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
    pub struct KeccakF1600;

    /// Make sure that we're compiling in a platform where
    /// the use of transmute for keccak evaluations is OK.
    const _: () = assert!(core::mem::size_of::<u64>() == 8 * core::mem::size_of::<u8>());

    impl Permutation<{ 136 + 64 }> for KeccakF1600 {
        type U = u8;

        fn permute(&self, state: &[u8; 200]) -> [u8; 200] {
            let mut new_state = *state;
            self.permute_mut(&mut new_state);
            new_state
        }

        fn permute_mut(&self, state: &mut [u8; 200]) {
            let mut words = [0u64; 25];
            unsafe {
                ptr::copy_nonoverlapping(
                    state.as_ptr(),
                    words.as_mut_ptr().cast::<u8>(),
                    state.len(),
                );
            }
            keccak::f1600(&mut words);
            unsafe {
                ptr::copy_nonoverlapping(
                    words.as_ptr().cast::<u8>(),
                    state.as_mut_ptr(),
                    state.len(),
                );
            }
        }
    }
}