mirror of https://github.com/PurpleI2P/i2pd
You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
131 lines
2.8 KiB
C++
131 lines
2.8 KiB
C++
#include "ChaCha20.h"
|
|
|
|
/**
|
|
This code is licensed under the MCGSI Public License
|
|
Copyright 2018 Jeff Becker
|
|
|
|
Kovri go write your own code
|
|
|
|
*/
|
|
|
|
#if LEGACY_OPENSSL
|
|
namespace i2p
|
|
{
|
|
namespace crypto
|
|
{
|
|
namespace chacha
|
|
{
|
|
constexpr int rounds = 20;
|
|
constexpr std::size_t blocksize = 64;
|
|
|
|
void u32t8le(uint32_t v, uint8_t * p)
|
|
{
|
|
p[0] = v & 0xff;
|
|
p[1] = (v >> 8) & 0xff;
|
|
p[2] = (v >> 16) & 0xff;
|
|
p[3] = (v >> 24) & 0xff;
|
|
}
|
|
|
|
uint32_t u8t32le(const uint8_t * p)
|
|
{
|
|
uint32_t value = p[3];
|
|
|
|
value = (value << 8) | p[2];
|
|
value = (value << 8) | p[1];
|
|
value = (value << 8) | p[0];
|
|
|
|
return value;
|
|
}
|
|
|
|
uint32_t rotl32(uint32_t x, int n)
|
|
{
|
|
return x << n | (x >> (-n & 31));
|
|
}
|
|
|
|
void quarterround(uint32_t *x, int a, int b, int c, int d)
|
|
{
|
|
x[a] += x[b]; x[d] = rotl32(x[d] ^ x[a], 16);
|
|
x[c] += x[d]; x[b] = rotl32(x[b] ^ x[c], 12);
|
|
x[a] += x[b]; x[d] = rotl32(x[d] ^ x[a], 8);
|
|
x[c] += x[d]; x[b] = rotl32(x[b] ^ x[c], 7);
|
|
}
|
|
|
|
|
|
struct Block_t
|
|
{
|
|
Block_t() {};
|
|
Block_t(Block_t &&) = delete;
|
|
|
|
uint8_t data[blocksize];
|
|
|
|
void operator << (const Chacha20State & st)
|
|
{
|
|
int i;
|
|
for (i = 0; i < 16; i++)
|
|
u32t8le(st.data[i], data + (i << 2));
|
|
}
|
|
};
|
|
|
|
void block(const Chacha20State &input, Block_t & block, int rounds)
|
|
{
|
|
int i;
|
|
Chacha20State x;
|
|
x.Copy(input);
|
|
|
|
for (i = rounds; i > 0; i -= 2)
|
|
{
|
|
quarterround(x.data, 0, 4, 8, 12);
|
|
quarterround(x.data, 1, 5, 9, 13);
|
|
quarterround(x.data, 2, 6, 10, 14);
|
|
quarterround(x.data, 3, 7, 11, 15);
|
|
quarterround(x.data, 0, 5, 10, 15);
|
|
quarterround(x.data, 1, 6, 11, 12);
|
|
quarterround(x.data, 2, 7, 8, 13);
|
|
quarterround(x.data, 3, 4, 9, 14);
|
|
}
|
|
x += input;
|
|
block << x;
|
|
|
|
}
|
|
} // namespace chacha
|
|
|
|
void Chacha20Init (Chacha20State& state, const uint8_t * nonce, const uint8_t * key, uint32_t counter)
|
|
{
|
|
state.data[0] = 0x61707865;
|
|
state.data[1] = 0x3320646e;
|
|
state.data[2] = 0x79622d32;
|
|
state.data[3] = 0x6b206574;
|
|
for (size_t i = 0; i < 8; i++)
|
|
state.data[4 + i] = chacha::u8t32le(key + i * 4);
|
|
|
|
state.data[12] = counter;
|
|
for (size_t i = 0; i < 3; i++)
|
|
state.data[13 + i] = chacha::u8t32le(nonce + i * 4);
|
|
}
|
|
|
|
void Chacha20Encrypt (Chacha20State& state, uint8_t * buf, size_t sz)
|
|
{
|
|
chacha::Block_t block;
|
|
for (size_t i = 0; i < sz; i += chacha::blocksize)
|
|
{
|
|
chacha::block(state, block, chacha::rounds);
|
|
state.data[12]++;
|
|
for (size_t j = i; j < i + chacha::blocksize; j++)
|
|
{
|
|
if (j >= sz) break;
|
|
buf[j] ^= block.data[j - i];
|
|
}
|
|
}
|
|
}
|
|
|
|
void chacha20(uint8_t * buf, size_t sz, const uint8_t * nonce, const uint8_t * key, uint32_t counter)
|
|
{
|
|
Chacha20State state;
|
|
Chacha20Init (state, nonce, key, counter);
|
|
Chacha20Encrypt (state, buf, sz);
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|