text: #include <string.h>
  #include "params.h"
  
  #define p 761
  #define Small_bytes ((p+3)/4)
  #define Rq_bytes 1158
  #define SecretKeys_bytes (2*Small_bytes)
  #define PublicKeys_bytes Rq_bytes
  
  int crypto_public_key_from_private_key(unsigned char* pk,
                                         const unsigned char* sk)
  {
      if (NULL != memcpy(pk,
                         sk + SecretKeys_bytes,
                         PublicKeys_bytes))
          return 0;
  
      return -1;
  }
  