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#![no_std] extern crate byteorder; mod ops; use byteorder::{ ByteOrder, LittleEndian }; pub use ops::Hc256Rng; #[derive(Clone)] pub struct HC256 { inner: Hc256Rng, buff: u32, count: usize } impl HC256 { pub fn new(key: &[u8], iv: &[u8]) -> HC256 { let mut w = [0; 2560]; for i in 0..8 { w[i] = LittleEndian::read_u32(&key[(i * 4)..((i + 1) * 4)]); w[i + 8] = LittleEndian::read_u32(&iv[(i * 4)..((i + 1) * 4)]); } HC256 { inner: Hc256Rng::with_w(&mut w), buff: 0, count: 0 } } pub fn process(&mut self, input: &[u8], output: &mut [u8]) { let mut pos = 0; if self.count != 0 && input.len() >= self.count { pos += self.count; for (i, b) in self.take(pos).enumerate() { output[i] = input[i] ^ b; } } while pos + 4 <= input.len() { let end = pos + 4; LittleEndian::write_u32( &mut output[pos..end], LittleEndian::read_u32(&input[pos..end]) ^ self.inner.gen() ); pos = end; } for b in self.take(input.len() - pos) { output[pos] = input[pos] ^ b; pos += 1; } } } impl Iterator for HC256 { type Item = u8; fn next(&mut self) -> Option<Self::Item> { if self.count == 0 { self.buff = self.inner.gen(); self.count = 4; } let output = (self.buff & 0xff) as u8; self.buff >>= 8; self.count -= 1; Some(output) } } #[test] fn test() { let mut output = [0; 32]; HC256::new(&[0; 32], &[0; 32]).process(&[0; 32], &mut output); assert_eq!( output, [ 0x5b, 0x07, 0x89, 0x85, 0xd8, 0xf6, 0xf3, 0x0d, 0x42, 0xc5, 0xc0, 0x2f, 0xa6, 0xb6, 0x79, 0x51, 0x53, 0xf0, 0x65, 0x34, 0x80, 0x1f, 0x89, 0xf2, 0x4e, 0x74, 0x24, 0x8b, 0x72, 0x0b, 0x48, 0x18 ] ); let mut iv = [0; 32]; iv[0] = 1; HC256::new(&[0; 32], &iv).process(&[0; 32], &mut output); assert_eq!( output, [ 0xaf, 0xe2, 0xa2, 0xbf, 0x4f, 0x17, 0xce, 0xe9, 0xfe, 0xc2, 0x05, 0x8b, 0xd1, 0xb1, 0x8b, 0xb1, 0x5f, 0xc0, 0x42, 0xee, 0x71, 0x2b, 0x31, 0x01, 0xdd, 0x50, 0x1f, 0xc6, 0x0b, 0x08, 0x2a, 0x50 ] ); let mut key = [0; 32]; key[0] = 0x55; HC256::new(&key, &[0; 32]).process(&[0; 32], &mut output); assert_eq!( output, [ 0x1c, 0x40, 0x4a, 0xfe, 0x4f, 0xe2, 0x5f, 0xed, 0x95, 0x8f, 0x9a, 0xd1, 0xae, 0x36, 0xc0, 0x6f, 0x88, 0xa6, 0x5a, 0x3c, 0xc0, 0xab, 0xe2, 0x23, 0xae, 0xb3, 0x90, 0x2f, 0x42, 0x0e, 0xd3, 0xa8 ] ); let mut key = [0; 32]; key[0] = 0x55; let mut cipher = HC256::new(&key, &[0; 32]); cipher.process(&[0; 11], &mut output[..11]); cipher.process(&[0; 21], &mut output[11..]); assert_eq!( output, [ 0x1c, 0x40, 0x4a, 0xfe, 0x4f, 0xe2, 0x5f, 0xed, 0x95, 0x8f, 0x9a, 0xd1, 0xae, 0x36, 0xc0, 0x6f, 0x88, 0xa6, 0x5a, 0x3c, 0xc0, 0xab, 0xe2, 0x23, 0xae, 0xb3, 0x90, 0x2f, 0x42, 0x0e, 0xd3, 0xa8 ] ); }