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//! An implementation of the SHA-1 cryptographic hash algorithm. //! To use this module, first create a `Sha1` object using the `Sha1` constructor, //! then feed it an input message using the `input` or `input_str` methods, //! which may be called any number of times; they will buffer the input until //! there is enough to call the block algorithm. //! //! After the entire input has been fed to the hash read the result using //! the `result` or `result_str` methods. The first will return bytes, and //! the second will return a `String` object of the same bytes represented //! in hexadecimal form. //! //! The `Sha1` object may be reused to create multiple hashes by calling //! the `reset()` method. These traits are implemented by all hash digest //! algorithms that implement the `Digest` trait. An example of use is: //! //! ```rust //! use sha1::{Sha1, Digest}; //! //! // create a Sha1 object //! let mut sh = Sha1::default(); //! //! // write input message //! sh.input(b"hello world"); //! //! // read hash digest in the form of GenericArray which is in this case //! // equivalent to [u8; 20] //! let output = sh.result(); //! assert_eq!(output[..], [0x2a, 0xae, 0x6c, 0x35, 0xc9, 0x4f, 0xcf, 0xb4, 0x15, 0xdb, //! 0xe9, 0x5f, 0x40, 0x8b, 0x9c, 0xe9, 0x1e, 0xe8, 0x46, 0xed]); //! ``` //! //! # Mathematics //! //! The mathematics of the SHA-1 algorithm are quite interesting. In its //! definition, The SHA-1 algorithm uses: //! //! * 1 binary operation on bit-arrays: //! * "exclusive or" (XOR) //! * 2 binary operations on integers: //! * "addition" (ADD) //! * "rotate left" (ROL) //! * 3 ternary operations on bit-arrays: //! * "choose" (CH) //! * "parity" (PAR) //! * "majority" (MAJ) //! //! Some of these functions are commonly found in all hash digest //! algorithms, but some, like "parity" is only found in SHA-1. #![no_std] extern crate block_buffer; extern crate byte_tools; #[macro_use] extern crate digest; #[cfg(not(feature = "asm"))] extern crate fake_simd as simd; #[cfg(feature = "asm")] extern crate sha1_asm as utils; #[cfg(not(feature = "asm"))] mod utils; use utils::compress; use byte_tools::write_u32v_be; use block_buffer::BlockBuffer512; pub use digest::Digest; use digest::generic_array::GenericArray; use digest::generic_array::typenum::{U20, U64}; mod consts; use consts::{STATE_LEN, H}; /// Structure representing the state of a SHA-1 computation #[derive(Clone)] pub struct Sha1 { h: [u32; STATE_LEN], len: u64, buffer: BlockBuffer512, } impl Default for Sha1 { fn default() -> Self { Sha1{ h: H, len: 0u64, buffer: Default::default() } } } impl digest::BlockInput for Sha1 { type BlockSize = U64; } impl digest::Input for Sha1 { fn process(&mut self, input: &[u8]) { // Assumes that `length_bits<<3` will not overflow self.len += input.len() as u64; let state = &mut self.h; self.buffer.input(input, |d| compress(state, d)); } } impl digest::FixedOutput for Sha1 { type OutputSize = U20; fn fixed_result(mut self) -> GenericArray<u8, Self::OutputSize> { { let state = &mut self.h; let l = self.len << 3; // remove this mess by adding `len_padding_be` method let l = if cfg!(target_endian = "little") { l.to_be() } else { l.to_le() }; self.buffer.len_padding(l, |d| compress(state, d)); } let mut out = GenericArray::default(); write_u32v_be(&mut out, &self.h); out } } impl_opaque_debug!(Sha1);