michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifdef FREEBL_NO_DEPEND
michael@0: #include "stubs.h"
michael@0: #endif
michael@0: 
michael@0: #include "blapi.h"
michael@0: #include "secerr.h"
michael@0: #include "secitem.h"
michael@0: #include "secmpi.h"
michael@0: 
michael@0: /* Hash an item's length and then its value. Only items smaller than 2^16 bytes
michael@0:  * are allowed. Lengths are hashed in network byte order. This is designed
michael@0:  * to match the OpenSSL J-PAKE implementation.
michael@0:  */
michael@0: static mp_err
michael@0: hashSECItem(HASHContext * hash, const SECItem * it)
michael@0: {
michael@0:     unsigned char length[2];
michael@0: 
michael@0:     if (it->len > 0xffff)
michael@0:         return MP_BADARG;
michael@0: 
michael@0:     length[0] = (unsigned char) (it->len >> 8);
michael@0:     length[1] = (unsigned char) (it->len);
michael@0:     hash->hashobj->update(hash->hash_context, length, 2);
michael@0:     hash->hashobj->update(hash->hash_context, it->data, it->len);
michael@0:     return MP_OKAY;
michael@0: }
michael@0: 
michael@0: /* Hash all public components of the signature, each prefixed with its
michael@0:    length, and then convert the hash to an mp_int. */
michael@0: static mp_err
michael@0: hashPublicParams(HASH_HashType hashType, const SECItem * g,
michael@0:                  const SECItem * gv, const SECItem * gx,
michael@0:                  const SECItem * signerID, mp_int * h)
michael@0: {
michael@0:     mp_err err;
michael@0:     unsigned char hBuf[HASH_LENGTH_MAX];
michael@0:     SECItem hItem;
michael@0:     HASHContext hash;
michael@0:     
michael@0:     hash.hashobj = HASH_GetRawHashObject(hashType);
michael@0:     if (hash.hashobj == NULL || hash.hashobj->length > sizeof hBuf) {
michael@0:         return MP_BADARG;
michael@0:     }
michael@0:     hash.hash_context = hash.hashobj->create();
michael@0:     if (hash.hash_context == NULL) {
michael@0:         return MP_MEM;
michael@0:     }
michael@0: 
michael@0:     hItem.data = hBuf;
michael@0:     hItem.len = hash.hashobj->length;
michael@0: 
michael@0:     hash.hashobj->begin(hash.hash_context);
michael@0:     CHECK_MPI_OK( hashSECItem(&hash, g) );
michael@0:     CHECK_MPI_OK( hashSECItem(&hash, gv) );
michael@0:     CHECK_MPI_OK( hashSECItem(&hash, gx) );
michael@0:     CHECK_MPI_OK( hashSECItem(&hash, signerID) );
michael@0:     hash.hashobj->end(hash.hash_context, hItem.data, &hItem.len,
michael@0:                       sizeof hBuf);
michael@0:     SECITEM_TO_MPINT(hItem, h);
michael@0: 
michael@0: cleanup:
michael@0:     if (hash.hash_context != NULL) {
michael@0:         hash.hashobj->destroy(hash.hash_context, PR_TRUE);
michael@0:     }
michael@0: 
michael@0:     return err;
michael@0: }
michael@0: 
michael@0: /* Generate a Schnorr signature for round 1 or round 2 */
michael@0: SECStatus
michael@0: JPAKE_Sign(PLArenaPool * arena, const PQGParams * pqg, HASH_HashType hashType,
michael@0:            const SECItem * signerID, const SECItem * x,
michael@0:            const SECItem * testRandom, const SECItem * gxIn, SECItem * gxOut,
michael@0:            SECItem * gv, SECItem * r)
michael@0: {
michael@0:     SECStatus rv = SECSuccess;
michael@0:     mp_err err;
michael@0:     mp_int p;
michael@0:     mp_int q;
michael@0:     mp_int g;
michael@0:     mp_int X;
michael@0:     mp_int GX;
michael@0:     mp_int V;
michael@0:     mp_int GV;
michael@0:     mp_int h;
michael@0:     mp_int tmp;
michael@0:     mp_int R;
michael@0:     SECItem v;
michael@0: 
michael@0:     if (!arena    ||
michael@0:         !pqg      || !pqg->prime.data     || pqg->prime.len == 0 ||
michael@0:                      !pqg->subPrime.data  || pqg->subPrime.len == 0 ||
michael@0:                      !pqg->base.data      || pqg->base.len == 0 ||
michael@0:         !signerID || !signerID->data      || signerID->len == 0 ||
michael@0:         !x        || !x->data             || x->len == 0 ||
michael@0:         (testRandom && (!testRandom->data || testRandom->len == 0)) ||
michael@0:         (gxIn == NULL && (!gxOut || gxOut->data != NULL)) ||
michael@0:         (gxIn != NULL && (!gxIn->data || gxIn->len == 0 || gxOut != NULL)) ||
michael@0:         !gv       || gv->data != NULL ||
michael@0:         !r        || r->data != NULL) {
michael@0:         PORT_SetError(SEC_ERROR_INVALID_ARGS);
michael@0:         return SECFailure;
michael@0:     }
michael@0: 
michael@0: 
michael@0:     MP_DIGITS(&p) = 0;
michael@0:     MP_DIGITS(&q) = 0;
michael@0:     MP_DIGITS(&g) = 0;
michael@0:     MP_DIGITS(&X) = 0;
michael@0:     MP_DIGITS(&GX) = 0;
michael@0:     MP_DIGITS(&V) = 0;
michael@0:     MP_DIGITS(&GV) = 0;
michael@0:     MP_DIGITS(&h) = 0;
michael@0:     MP_DIGITS(&tmp) = 0;
michael@0:     MP_DIGITS(&R) = 0;
michael@0: 
michael@0:     CHECK_MPI_OK( mp_init(&p) );
michael@0:     CHECK_MPI_OK( mp_init(&q) );
michael@0:     CHECK_MPI_OK( mp_init(&g) );
michael@0:     CHECK_MPI_OK( mp_init(&X) );
michael@0:     CHECK_MPI_OK( mp_init(&GX) );
michael@0:     CHECK_MPI_OK( mp_init(&V) );
michael@0:     CHECK_MPI_OK( mp_init(&GV) );
michael@0:     CHECK_MPI_OK( mp_init(&h) );
michael@0:     CHECK_MPI_OK( mp_init(&tmp) );
michael@0:     CHECK_MPI_OK( mp_init(&R) );
michael@0: 
michael@0:     SECITEM_TO_MPINT(pqg->prime, &p);
michael@0:     SECITEM_TO_MPINT(pqg->subPrime, &q);
michael@0:     SECITEM_TO_MPINT(pqg->base, &g);
michael@0:     SECITEM_TO_MPINT(*x,  &X);
michael@0: 
michael@0:     /* gx = g^x */
michael@0:     if (gxIn == NULL) {
michael@0:         CHECK_MPI_OK( mp_exptmod(&g, &X, &p, &GX) );
michael@0:         MPINT_TO_SECITEM(&GX, gxOut, arena);
michael@0:         gxIn = gxOut;
michael@0:     } else {
michael@0:         SECITEM_TO_MPINT(*gxIn, &GX);
michael@0:     }
michael@0: 
michael@0:     /* v is a random value in the q subgroup */
michael@0:     if (testRandom == NULL) {
michael@0:         v.data = NULL;
michael@0:         rv = DSA_NewRandom(arena, &pqg->subPrime, &v);
michael@0:         if (rv != SECSuccess) {
michael@0:             goto cleanup;
michael@0:         }
michael@0:     } else {
michael@0:         v.data = testRandom->data;
michael@0:         v.len = testRandom->len;
michael@0:     }
michael@0:     SECITEM_TO_MPINT(v, &V);
michael@0: 
michael@0:     /* gv = g^v (mod q), random v, 1 <= v < q */
michael@0:     CHECK_MPI_OK( mp_exptmod(&g, &V, &p, &GV) );
michael@0:     MPINT_TO_SECITEM(&GV, gv, arena);
michael@0: 
michael@0:     /* h = H(g, gv, gx, signerID) */
michael@0:     CHECK_MPI_OK( hashPublicParams(hashType, &pqg->base, gv, gxIn, signerID,
michael@0:                                    &h) );
michael@0: 
michael@0:     /* r = v - x*h (mod q) */
michael@0:     CHECK_MPI_OK( mp_mulmod(&X, &h, &q, &tmp) );
michael@0:     CHECK_MPI_OK( mp_submod(&V, &tmp, &q, &R) );
michael@0:     MPINT_TO_SECITEM(&R, r, arena);
michael@0: 
michael@0: cleanup:
michael@0:     mp_clear(&p);
michael@0:     mp_clear(&q);
michael@0:     mp_clear(&g);
michael@0:     mp_clear(&X);
michael@0:     mp_clear(&GX);
michael@0:     mp_clear(&V);
michael@0:     mp_clear(&GV);
michael@0:     mp_clear(&h);
michael@0:     mp_clear(&tmp);
michael@0:     mp_clear(&R);
michael@0: 
michael@0:     if (rv == SECSuccess && err != MP_OKAY) {
michael@0:         MP_TO_SEC_ERROR(err);
michael@0:         rv = SECFailure;
michael@0:     }
michael@0:     return rv;
michael@0: }
michael@0: 
michael@0: /* Verify a Schnorr signature generated by the peer in round 1 or round 2. */
michael@0: SECStatus
michael@0: JPAKE_Verify(PLArenaPool * arena, const PQGParams * pqg, HASH_HashType hashType,
michael@0:              const SECItem * signerID, const SECItem * peerID,
michael@0:              const SECItem * gx, const SECItem * gv, const SECItem * r)
michael@0: {
michael@0:     SECStatus rv = SECSuccess;
michael@0:     mp_err err;
michael@0:     mp_int p;
michael@0:     mp_int q;
michael@0:     mp_int g;
michael@0:     mp_int p_minus_1;
michael@0:     mp_int GX;
michael@0:     mp_int h;
michael@0:     mp_int one;
michael@0:     mp_int R;
michael@0:     mp_int gr;
michael@0:     mp_int gxh;
michael@0:     mp_int gr_gxh;
michael@0:     SECItem calculated;
michael@0: 
michael@0:     if (!arena    ||
michael@0:         !pqg      || !pqg->prime.data    || pqg->prime.len == 0 ||
michael@0:                      !pqg->subPrime.data || pqg->subPrime.len == 0 ||
michael@0:                      !pqg->base.data     || pqg->base.len == 0 ||
michael@0:         !signerID || !signerID->data  || signerID->len == 0 ||
michael@0:         !peerID   || !peerID->data    || peerID->len == 0 ||
michael@0:         !gx       || !gx->data        || gx->len == 0 ||
michael@0:         !gv       || !gv->data        || gv->len == 0 ||
michael@0:         !r        || !r->data         || r->len == 0 ||
michael@0:         SECITEM_CompareItem(signerID, peerID) == SECEqual) {
michael@0:         PORT_SetError(SEC_ERROR_INVALID_ARGS);
michael@0:         return SECFailure;
michael@0:     }
michael@0: 
michael@0:     MP_DIGITS(&p) = 0;
michael@0:     MP_DIGITS(&q) = 0;
michael@0:     MP_DIGITS(&g) = 0;
michael@0:     MP_DIGITS(&p_minus_1) = 0;
michael@0:     MP_DIGITS(&GX) = 0;
michael@0:     MP_DIGITS(&h) = 0;
michael@0:     MP_DIGITS(&one) = 0;
michael@0:     MP_DIGITS(&R) = 0;
michael@0:     MP_DIGITS(&gr) = 0;
michael@0:     MP_DIGITS(&gxh) = 0;
michael@0:     MP_DIGITS(&gr_gxh) = 0;
michael@0:     calculated.data = NULL;
michael@0: 
michael@0:     CHECK_MPI_OK( mp_init(&p) );
michael@0:     CHECK_MPI_OK( mp_init(&q) );
michael@0:     CHECK_MPI_OK( mp_init(&g) );
michael@0:     CHECK_MPI_OK( mp_init(&p_minus_1) );
michael@0:     CHECK_MPI_OK( mp_init(&GX) );
michael@0:     CHECK_MPI_OK( mp_init(&h) );
michael@0:     CHECK_MPI_OK( mp_init(&one) );
michael@0:     CHECK_MPI_OK( mp_init(&R) );
michael@0:     CHECK_MPI_OK( mp_init(&gr) );
michael@0:     CHECK_MPI_OK( mp_init(&gxh) );
michael@0:     CHECK_MPI_OK( mp_init(&gr_gxh) );
michael@0: 
michael@0:     SECITEM_TO_MPINT(pqg->prime, &p);
michael@0:     SECITEM_TO_MPINT(pqg->subPrime, &q);
michael@0:     SECITEM_TO_MPINT(pqg->base, &g);
michael@0:     SECITEM_TO_MPINT(*gx, &GX);
michael@0:     SECITEM_TO_MPINT(*r, &R);
michael@0: 
michael@0:     CHECK_MPI_OK( mp_sub_d(&p, 1, &p_minus_1) );
michael@0:     CHECK_MPI_OK( mp_exptmod(&GX, &q, &p, &one) );
michael@0:     /* Check g^x is in [1, p-2], R is in [0, q-1], and (g^x)^q mod p == 1 */
michael@0:     if (!(mp_cmp_z(&GX) > 0 && 
michael@0:           mp_cmp(&GX, &p_minus_1) < 0 && 
michael@0:           mp_cmp(&R, &q) < 0 &&
michael@0:           mp_cmp_d(&one, 1) == 0)) {
michael@0:         goto badSig;
michael@0:     }
michael@0:     
michael@0:     CHECK_MPI_OK( hashPublicParams(hashType, &pqg->base, gv, gx, peerID,
michael@0:                                    &h) );
michael@0: 
michael@0:     /* Calculate g^v = g^r * g^x^h */
michael@0:     CHECK_MPI_OK( mp_exptmod(&g, &R, &p, &gr) );
michael@0:     CHECK_MPI_OK( mp_exptmod(&GX, &h, &p, &gxh) );
michael@0:     CHECK_MPI_OK( mp_mulmod(&gr, &gxh, &p, &gr_gxh) );
michael@0: 
michael@0:     /* Compare calculated g^v to given g^v */
michael@0:     MPINT_TO_SECITEM(&gr_gxh, &calculated, arena);
michael@0:     if (calculated.len == gv->len &&
michael@0:         NSS_SecureMemcmp(calculated.data, gv->data, calculated.len) == 0) {
michael@0:         rv = SECSuccess;
michael@0:     } else {
michael@0: badSig: PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
michael@0:         rv = SECFailure;
michael@0:     }
michael@0: 
michael@0: cleanup:
michael@0:     mp_clear(&p);
michael@0:     mp_clear(&q);
michael@0:     mp_clear(&g);
michael@0:     mp_clear(&p_minus_1);
michael@0:     mp_clear(&GX);
michael@0:     mp_clear(&h);
michael@0:     mp_clear(&one);
michael@0:     mp_clear(&R);
michael@0:     mp_clear(&gr);
michael@0:     mp_clear(&gxh);
michael@0:     mp_clear(&gr_gxh);
michael@0:  
michael@0:     if (rv == SECSuccess && err != MP_OKAY) {
michael@0:         MP_TO_SEC_ERROR(err);
michael@0:         rv = SECFailure;
michael@0:     }
michael@0:     return rv;
michael@0: }
michael@0: 
michael@0: /* Calculate base = gx1*gx3*gx4 (mod p), i.e. g^(x1+x3+x4) (mod p) */
michael@0: static mp_err
michael@0: jpake_Round2Base(const SECItem * gx1, const SECItem * gx3,
michael@0:                  const SECItem * gx4, const mp_int * p, mp_int * base)
michael@0: {
michael@0:     mp_err err;
michael@0:     mp_int GX1;
michael@0:     mp_int GX3;
michael@0:     mp_int GX4;
michael@0:     mp_int tmp;
michael@0: 
michael@0:     MP_DIGITS(&GX1) = 0;
michael@0:     MP_DIGITS(&GX3) = 0;
michael@0:     MP_DIGITS(&GX4) = 0;
michael@0:     MP_DIGITS(&tmp) = 0;
michael@0: 
michael@0:     CHECK_MPI_OK( mp_init(&GX1) );
michael@0:     CHECK_MPI_OK( mp_init(&GX3) );
michael@0:     CHECK_MPI_OK( mp_init(&GX4) );
michael@0:     CHECK_MPI_OK( mp_init(&tmp) );
michael@0: 
michael@0:     SECITEM_TO_MPINT(*gx1, &GX1);
michael@0:     SECITEM_TO_MPINT(*gx3, &GX3);
michael@0:     SECITEM_TO_MPINT(*gx4, &GX4);
michael@0: 
michael@0:     /* In round 2, the peer/attacker sends us g^x3 and g^x4 and the protocol
michael@0:        requires that these values are distinct. */
michael@0:     if (mp_cmp(&GX3, &GX4) == 0) {
michael@0:         return MP_BADARG;
michael@0:     }
michael@0:     
michael@0:     CHECK_MPI_OK( mp_mul(&GX1, &GX3, &tmp) );
michael@0:     CHECK_MPI_OK( mp_mul(&tmp, &GX4, &tmp) ); 
michael@0:     CHECK_MPI_OK( mp_mod(&tmp, p, base) );
michael@0: 
michael@0: cleanup:
michael@0:     mp_clear(&GX1);
michael@0:     mp_clear(&GX3);
michael@0:     mp_clear(&GX4);
michael@0:     mp_clear(&tmp);
michael@0:     return err;
michael@0: }
michael@0: 
michael@0: SECStatus
michael@0: JPAKE_Round2(PLArenaPool * arena,
michael@0:              const SECItem * p, const SECItem  *q, const SECItem * gx1,
michael@0:              const SECItem * gx3, const SECItem * gx4, SECItem * base,
michael@0:              const SECItem * x2, const SECItem * s, SECItem * x2s)
michael@0: {
michael@0:     mp_err err;
michael@0:     mp_int P;
michael@0:     mp_int Q;
michael@0:     mp_int X2;
michael@0:     mp_int S;
michael@0:     mp_int result;
michael@0: 
michael@0:     if (!arena ||
michael@0:         !p     || !p->data    || p->len == 0   ||
michael@0:         !q     || !q->data    || q->len == 0   ||
michael@0:         !gx1   || !gx1->data  || gx1->len == 0 ||
michael@0:         !gx3   || !gx3->data  || gx3->len == 0 ||
michael@0:         !gx4   || !gx4->data  || gx4->len == 0 ||
michael@0:         !base  || base->data != NULL ||
michael@0:         (x2s != NULL && (x2s->data != NULL ||
michael@0:            !x2 || !x2->data   || x2->len == 0 ||
michael@0:            !s  || !s->data    || s->len == 0))) {
michael@0:         PORT_SetError(SEC_ERROR_INVALID_ARGS);
michael@0:         return SECFailure;
michael@0:     }
michael@0: 
michael@0:     MP_DIGITS(&P) = 0;
michael@0:     MP_DIGITS(&Q) = 0;
michael@0:     MP_DIGITS(&X2) = 0;
michael@0:     MP_DIGITS(&S) = 0;
michael@0:     MP_DIGITS(&result) = 0;
michael@0: 
michael@0:     CHECK_MPI_OK( mp_init(&P) );
michael@0:     CHECK_MPI_OK( mp_init(&Q) );
michael@0:     CHECK_MPI_OK( mp_init(&result) );
michael@0: 
michael@0:     if (x2s != NULL) {
michael@0:         CHECK_MPI_OK( mp_init(&X2) );
michael@0:         CHECK_MPI_OK( mp_init(&S) );
michael@0: 
michael@0:         SECITEM_TO_MPINT(*q, &Q);
michael@0:         SECITEM_TO_MPINT(*x2, &X2);
michael@0:         
michael@0:         SECITEM_TO_MPINT(*s, &S);
michael@0:         /* S must be in [1, Q-1] */
michael@0:         if (mp_cmp_z(&S) <= 0 || mp_cmp(&S, &Q) >= 0) {
michael@0:             err = MP_BADARG;
michael@0:             goto cleanup;
michael@0:         }
michael@0: 
michael@0:         CHECK_MPI_OK( mp_mulmod(&X2, &S, &Q, &result) );
michael@0:         MPINT_TO_SECITEM(&result, x2s, arena);
michael@0:     }
michael@0: 
michael@0:     SECITEM_TO_MPINT(*p, &P);
michael@0:     CHECK_MPI_OK( jpake_Round2Base(gx1, gx3, gx4, &P, &result) );
michael@0:     MPINT_TO_SECITEM(&result, base, arena);
michael@0: 
michael@0: cleanup:
michael@0:     mp_clear(&P);
michael@0:     mp_clear(&Q);
michael@0:     mp_clear(&X2);
michael@0:     mp_clear(&S);
michael@0:     mp_clear(&result);
michael@0: 
michael@0:     if (err != MP_OKAY) {
michael@0:         MP_TO_SEC_ERROR(err);
michael@0:         return SECFailure;
michael@0:     }
michael@0:     return SECSuccess;
michael@0: }
michael@0: 
michael@0: SECStatus
michael@0: JPAKE_Final(PLArenaPool * arena, const SECItem * p, const SECItem * q,
michael@0:             const SECItem * x2, const SECItem * gx4, const SECItem * x2s,
michael@0:             const SECItem * B, SECItem * K)
michael@0: {
michael@0:     mp_err err;
michael@0:     mp_int P;
michael@0:     mp_int Q;
michael@0:     mp_int tmp;
michael@0:     mp_int exponent;
michael@0:     mp_int divisor;
michael@0:     mp_int base;
michael@0: 
michael@0:     if (!arena ||
michael@0:         !p     || !p->data    || p->len == 0   ||
michael@0:         !q     || !q->data    || q->len == 0   ||
michael@0:         !x2    || !x2->data   || x2->len == 0  ||
michael@0:         !gx4   || !gx4->data  || gx4->len == 0 ||
michael@0:         !x2s   || !x2s->data  || x2s->len == 0 ||
michael@0:         !B     || !B->data    || B->len == 0 ||
michael@0:         !K     || K->data != NULL) {
michael@0:         PORT_SetError(SEC_ERROR_INVALID_ARGS);
michael@0:         return SECFailure;
michael@0:     }
michael@0: 
michael@0:     MP_DIGITS(&P) = 0;
michael@0:     MP_DIGITS(&Q) = 0;
michael@0:     MP_DIGITS(&tmp) = 0;
michael@0:     MP_DIGITS(&exponent) = 0;
michael@0:     MP_DIGITS(&divisor) = 0;
michael@0:     MP_DIGITS(&base) = 0;
michael@0: 
michael@0:     CHECK_MPI_OK( mp_init(&P) );
michael@0:     CHECK_MPI_OK( mp_init(&Q) );
michael@0:     CHECK_MPI_OK( mp_init(&tmp) );
michael@0:     CHECK_MPI_OK( mp_init(&exponent) );
michael@0:     CHECK_MPI_OK( mp_init(&divisor) );
michael@0:     CHECK_MPI_OK( mp_init(&base) );
michael@0: 
michael@0:     /* exponent = -x2s (mod q) */
michael@0:     SECITEM_TO_MPINT(*q, &Q);
michael@0:     SECITEM_TO_MPINT(*x2s, &tmp);
michael@0:     /*  q == 0 (mod q), so q - x2s == -x2s (mod q) */
michael@0:     CHECK_MPI_OK( mp_sub(&Q, &tmp, &exponent) );
michael@0: 
michael@0:     /* divisor = gx4^-x2s = 1/(gx4^x2s) (mod p) */
michael@0:     SECITEM_TO_MPINT(*p, &P);
michael@0:     SECITEM_TO_MPINT(*gx4, &tmp);
michael@0:     CHECK_MPI_OK( mp_exptmod(&tmp, &exponent, &P, &divisor) );
michael@0:     
michael@0:     /* base = B*divisor = B/(gx4^x2s) (mod p) */
michael@0:     SECITEM_TO_MPINT(*B, &tmp);
michael@0:     CHECK_MPI_OK( mp_mulmod(&divisor, &tmp, &P, &base) );
michael@0: 
michael@0:     /* tmp = base^x2 (mod p) */
michael@0:     SECITEM_TO_MPINT(*x2, &exponent);
michael@0:     CHECK_MPI_OK( mp_exptmod(&base, &exponent, &P, &tmp) );
michael@0: 
michael@0:     MPINT_TO_SECITEM(&tmp, K, arena);
michael@0: 
michael@0: cleanup:
michael@0:     mp_clear(&P);
michael@0:     mp_clear(&Q);
michael@0:     mp_clear(&tmp);
michael@0:     mp_clear(&exponent);
michael@0:     mp_clear(&divisor);
michael@0:     mp_clear(&base);
michael@0: 
michael@0:     if (err != MP_OKAY) {
michael@0:         MP_TO_SEC_ERROR(err);
michael@0:         return SECFailure;
michael@0:     }
michael@0:     return SECSuccess;
michael@0: }