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To reference or cite the objects present in the Software Heritage archive, permalinks based on SoftWare Hash IDentifiers (SWHIDs) must be used.
Select below a type of object currently browsed in order to display its associated SWHID and permalink.

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Citations

This interface enables to generate software citations, provided that the root directory of browsed objects contains a citation.cff or codemeta.json file.
Select below a type of object currently browsed in order to generate citations for them.

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Generate software citation in BibTex format (requires biblatex-software package)
Generating citation ...
/* Deterministic randombytes by Daniel J. Bernstein */
/* taken from SUPERCOP (https://bench.cr.yp.to)     */

#include "api.h"
#include "randombytes.h"
#include "hal.h"

#include <stdio.h>
#include <string.h>
#include <stdint.h>

#define MAXMLEN 2048

// https://stackoverflow.com/a/1489985/1711232
#define PASTER(x, y) x##y
#define EVALUATOR(x, y) PASTER(x, y)
#define NAMESPACE(fun) EVALUATOR(MUPQ_NAMESPACE, fun)

// use different names so we can have empty namespaces
#define MUPQ_CRYPTO_PUBLICKEYBYTES NAMESPACE(CRYPTO_PUBLICKEYBYTES)
#define MUPQ_CRYPTO_SECRETKEYBYTES NAMESPACE(CRYPTO_SECRETKEYBYTES)
#define MUPQ_CRYPTO_BYTES          NAMESPACE(CRYPTO_BYTES)
#define MUPQ_CRYPTO_ALGNAME        NAMESPACE(CRYPTO_ALGNAME)

#define MUPQ_crypto_sign_keypair NAMESPACE(crypto_sign_keypair)
#define MUPQ_crypto_sign NAMESPACE(crypto_sign)
#define MUPQ_crypto_sign_open NAMESPACE(crypto_sign_open)
#define MUPQ_crypto_sign_signature NAMESPACE(crypto_sign_signature)
#define MUPQ_crypto_sign_verify NAMESPACE(crypto_sign_verify)

typedef uint32_t uint32;

static void printbytes(const unsigned char *x, unsigned long long xlen)
{
  char outs[2*xlen+1];
  unsigned long long i;
  for(i=0;i<xlen;i++)
    sprintf(outs+2*i, "%02x", x[i]);
  outs[2*xlen] = 0;
  hal_send_str(outs);
}

static uint32 seed[32] = { 3,1,4,1,5,9,2,6,5,3,5,8,9,7,9,3,2,3,8,4,6,2,6,4,3,3,8,3,2,7,9,5 } ;
static uint32 in[12];
static uint32 out[8];
static int outleft = 0;

#define ROTATE(x,b) (((x) << (b)) | ((x) >> (32 - (b))))
#define MUSH(i,b) x = t[i] += (((x ^ seed[i]) + sum) ^ ROTATE(x,b));

static void surf(void)
{
  uint32 t[12]; uint32 x; uint32 sum = 0;
  int r; int i; int loop;

  for (i = 0;i < 12;++i) t[i] = in[i] ^ seed[12 + i];
  for (i = 0;i < 8;++i) out[i] = seed[24 + i];
  x = t[11];
  for (loop = 0;loop < 2;++loop) {
    for (r = 0;r < 16;++r) {
      sum += 0x9e3779b9;
      MUSH(0,5) MUSH(1,7) MUSH(2,9) MUSH(3,13)
      MUSH(4,5) MUSH(5,7) MUSH(6,9) MUSH(7,13)
      MUSH(8,5) MUSH(9,7) MUSH(10,9) MUSH(11,13)
    }
    for (i = 0;i < 8;++i) out[i] ^= t[i + 4];
  }
}

int randombytes(uint8_t *x, size_t xlen)
{
  while (xlen > 0) {
    if (!outleft) {
      if (!++in[0]) if (!++in[1]) if (!++in[2]) ++in[3];
      surf();
      outleft = 8;
    }
    *x = out[--outleft];
    ++x;
    --xlen;
  }
  return 0;
}

int main(void)
{
  unsigned char sk[MUPQ_CRYPTO_SECRETKEYBYTES];
  unsigned char pk[MUPQ_CRYPTO_PUBLICKEYBYTES];

  unsigned char mi[MAXMLEN];
  unsigned char sm[MAXMLEN+MUPQ_CRYPTO_BYTES];
  size_t smlen;
  size_t mlen;

  int r;
  size_t i,j;

  hal_setup(CLOCK_FAST);

  hal_send_str("==========================");

  for(i=0; i<MAXMLEN; i=(i==0)?i+1:i<<1)
  {
    randombytes(mi,i);

    MUPQ_crypto_sign_keypair(pk, sk);

    printbytes(pk,MUPQ_CRYPTO_PUBLICKEYBYTES);
    printbytes(sk,MUPQ_CRYPTO_SECRETKEYBYTES);

    MUPQ_crypto_sign(sm, &smlen, mi, i, sk);

    printbytes(sm, smlen);

    // By relying on m == sm we prevent having to allocate CRYPTO_BYTES twice
    r = MUPQ_crypto_sign_open(sm, &mlen, sm, smlen, pk);

    if(r)
    {
      hal_send_str("ERROR: signature verification failed");
      hal_send_str("#");
      return -1;
    }
    for(j=0;j<i;j++)
    {
      if(sm[j]!=mi[j])
      {
        hal_send_str("ERROR: message recovery failed");
        hal_send_str("#");
        return -1;
      }
    }
  }

  hal_send_str("#");
  return 0;
}

Software Heritage — Copyright (C) 2015–2025, The Software Heritage developers. License: GNU AGPLv3+.
The source code of Software Heritage itself is available on our development forge.
The source code files archived by Software Heritage are available under their own copyright and licenses.
Terms of use: Archive access, API— Contact— JavaScript license information— Web API

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