Files
MP-SPDZ/Tools/random.h
2016-09-02 19:16:51 +01:00

85 lines
1.8 KiB
C++

// (C) 2016 University of Bristol. See License.txt
#ifndef _random
#define _random
#include "Tools/octetStream.h"
#include "Tools/sha1.h"
#include "Tools/aes.h"
#define USE_AES
#ifndef USE_AES
#define PIPELINES 1
#define SEED_SIZE HASH_SIZE
#define RAND_SIZE HASH_SIZE
#else
#define PIPELINES 8
#define SEED_SIZE AES_BLK_SIZE
#define RAND_SIZE (PIPELINES * AES_BLK_SIZE)
#endif
/* This basically defines a randomness expander, if using
* as a real PRG on an input stream you should first collapse
* the input stream down to a SEED, say via CBC-MAC (under 0 key)
* or via a hash
*/
// __attribute__ is needed to get the sse instructions to avoid
// seg faulting.
class PRNG
{
octet seed[SEED_SIZE];
octet state[RAND_SIZE] __attribute__((aligned (16)));
octet random[RAND_SIZE] __attribute__((aligned (16)));
#ifdef USE_AES
bool useC;
// Two types of key schedule for the different implementations
// of AES
uint KeyScheduleC[44];
octet KeySchedule[176] __attribute__((aligned (16)));
#endif
int cnt; // How many bytes of the current random value have been used
void hash(); // Hashes state to random and sets cnt=0
void next();
public:
PRNG();
// For debugging
void print_state() const;
// Set seed from dev/random
void ReSeed();
// Set seed from array
void SetSeed(unsigned char*);
void InitSeed();
double get_double();
unsigned char get_uchar();
unsigned int get_uint();
bigint randomBnd(const bigint& B);
word get_word()
{ word a=get_uint();
a<<=32;
a+=get_uint();
return a;
}
__m128i get_doubleword();
void get_octetStream(octetStream& ans,int len);
void get_octets(octet* ans, int len);
const octet* get_seed() const
{ return seed; }
};
#endif