ed25519-donna-batchverify.h File Reference

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Classes
struct	batch_heap_t

Macros
#define	max_batch_size   64
#define	heap_batch_size   ((max_batch_size * 2) + 1)

Typedefs
typedef size_t	heap_index_t
typedef struct batch_heap_t	batch_heap

Functions
int ED25519_FN	ed25519_sign_open_batch (const unsigned char **m, size_t *mlen, const unsigned char **pk, const unsigned char **RS, size_t num, int *valid)

Variables
unsigned char	batch_point_buffer [3][32]

Macro Definition Documentation

heap_batch_size

#define heap_batch_size   ((max_batch_size * 2) + 1)

Definition at line 6 of file ed25519-donna-batchverify.h.

max_batch_size

#define max_batch_size   64

Definition at line 5 of file ed25519-donna-batchverify.h.

Typedef Documentation

batch_heap

typedef struct batch_heap_t batch_heap

heap_index_t

typedef size_t heap_index_t

Definition at line 11 of file ed25519-donna-batchverify.h.

Function Documentation

ed25519_sign_open_batch()

int ED25519_FN ed25519_sign_open_batch	(	const unsigned char **	m,
		size_t *	mlen,
		const unsigned char **	pk,
		const unsigned char **	RS,
		size_t	num,
		int *	valid )

Definition at line 205 of file ed25519-donna-batchverify.h.

                                                                                                                                                        {
    batch_heap ALIGN(16) batch;
    ge25519 ALIGN(16) p;
    bignum256modm *r_scalars;
    size_t i, batchsize;
    unsigned char hram[64];
    int ret = 0;
 
    for (i = 0; i < num; i++)
        valid[i] = 1;
 
    while (num > 3) {
        batchsize = (num > max_batch_size) ? max_batch_size : num;
 
        /* generate r (scalars[batchsize+1]..scalars[2*batchsize] */
        ED25519_FN(ed25519_randombytes_unsafe) (batch.r, batchsize * 16);
        r_scalars = &batch.scalars[batchsize + 1];
        for (i = 0; i < batchsize; i++)
            expand256_modm(r_scalars[i], batch.r[i], 16);
 
        /* compute scalars[0] = ((r1s1 + r2s2 + ...)) */
        for (i = 0; i < batchsize; i++) {
            expand256_modm(batch.scalars[i], RS[i] + 32, 32);
            mul256_modm(batch.scalars[i], batch.scalars[i], r_scalars[i]);
        }
        for (i = 1; i < batchsize; i++)
            add256_modm(batch.scalars[0], batch.scalars[0], batch.scalars[i]);
 
        /* compute scalars[1]..scalars[batchsize] as r[i]*H(R[i],A[i],m[i]) */
        for (i = 0; i < batchsize; i++) {
            ed25519_hram(hram, RS[i], pk[i], m[i], mlen[i]);
            expand256_modm(batch.scalars[i+1], hram, 64);
            mul256_modm(batch.scalars[i+1], batch.scalars[i+1], r_scalars[i]);
        }
 
        /* compute points */
        batch.points[0] = ge25519_basepoint;
        for (i = 0; i < batchsize; i++)
            if (!ge25519_unpack_negative_vartime(&batch.points[i+1], pk[i]))
                goto fallback;
        for (i = 0; i < batchsize; i++)
            if (!ge25519_unpack_negative_vartime(&batch.points[batchsize+i+1], RS[i]))
                goto fallback;
 
        ge25519_multi_scalarmult_vartime(&p, &batch, (batchsize * 2) + 1);
        if (!ge25519_is_neutral_vartime(&p)) {
            ret |= 2;
 
            fallback:
            for (i = 0; i < batchsize; i++) {
                valid[i] = ED25519_FN(ed25519_sign_open) (m[i], mlen[i], pk[i], RS[i]) ? 0 : 1;
                ret |= (valid[i] ^ 1);
            }
        }
 
        m += batchsize;
        mlen += batchsize;
        pk += batchsize;
        RS += batchsize;
        num -= batchsize;
        valid += batchsize;
    }
 
    for (i = 0; i < num; i++) {
        valid[i] = ED25519_FN(ed25519_sign_open) (m[i], mlen[i], pk[i], RS[i]) ? 0 : 1;
        ret |= (valid[i] ^ 1);
    }
 
    return ret;
}

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Variable Documentation

batch_point_buffer

unsigned char batch_point_buffer[3][32]

Definition at line 191 of file ed25519-donna-batchverify.h.