lokinet/crypto/xchacha20/stream_xchacha20.c

#include <stdlib.h>

#include <sodium/crypto_core_hchacha20.h>
#include <sodium/crypto_stream_chacha20.h>
#include <sodium/crypto_stream_xchacha20.h>
#include <sodium/private/common.h>
#include <sodium/randombytes.h>

size_t
crypto_stream_xchacha20_keybytes(void)
{
  return crypto_stream_xchacha20_KEYBYTES;
}

size_t
crypto_stream_xchacha20_noncebytes(void)
{
  return crypto_stream_xchacha20_NONCEBYTES;
}

size_t
crypto_stream_xchacha20_messagebytes_max(void)
{
  return crypto_stream_xchacha20_MESSAGEBYTES_MAX;
}

int
crypto_stream_xchacha20(unsigned char *c, unsigned long long clen,
                        const unsigned char *n, const unsigned char *k)
{
  unsigned char k2[crypto_core_hchacha20_OUTPUTBYTES];

  crypto_core_hchacha20(k2, n, k, NULL);
  COMPILER_ASSERT(crypto_stream_chacha20_KEYBYTES <= sizeof k2);
  COMPILER_ASSERT(crypto_stream_chacha20_NONCEBYTES
                  == crypto_stream_xchacha20_NONCEBYTES
                      - crypto_core_hchacha20_INPUTBYTES);

  return crypto_stream_chacha20(c, clen, n + crypto_core_hchacha20_INPUTBYTES,
                                k2);
}

int
crypto_stream_xchacha20_xor_ic(unsigned char *c, const unsigned char *m,
                               unsigned long long mlen, const unsigned char *n,
                               uint64_t ic, const unsigned char *k)
{
  unsigned char k2[crypto_core_hchacha20_OUTPUTBYTES];

  crypto_core_hchacha20(k2, n, k, NULL);
  return crypto_stream_chacha20_xor_ic(
      c, m, mlen, n + crypto_core_hchacha20_INPUTBYTES, ic, k2);
}

int
crypto_stream_xchacha20_xor(unsigned char *c, const unsigned char *m,
                            unsigned long long mlen, const unsigned char *n,
                            const unsigned char *k)
{
  return crypto_stream_xchacha20_xor_ic(c, m, mlen, n, 0U, k);
}

void
crypto_stream_xchacha20_keygen(
    unsigned char k[crypto_stream_xchacha20_KEYBYTES])
{
  randombytes_buf(k, crypto_stream_xchacha20_KEYBYTES);
}