/* Copyright (c) 2020, Google Inc. * * Permission to use, copy, modify, and/or distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #include #include #include #include #include #include #include #include #include #include "../ec_extra/internal.h" #include "../fipsmodule/bn/internal.h" #include "../fipsmodule/ec/internal.h" #include "internal.h" typedef int (*hash_t_func_t)(const EC_GROUP *group, EC_RAW_POINT *out, const uint8_t t[TRUST_TOKEN_NONCE_SIZE]); typedef int (*hash_s_func_t)(const EC_GROUP *group, EC_RAW_POINT *out, const EC_AFFINE *t, const uint8_t s[TRUST_TOKEN_NONCE_SIZE]); typedef int (*hash_c_func_t)(const EC_GROUP *group, EC_SCALAR *out, uint8_t *buf, size_t len); typedef struct { const EC_GROUP *group; EC_PRECOMP g_precomp; EC_PRECOMP h_precomp; EC_RAW_POINT h; // hash_t implements the H_t operation in PMBTokens. It returns one on success // and zero on error. hash_t_func_t hash_t; // hash_s implements the H_s operation in PMBTokens. It returns one on success // and zero on error. hash_s_func_t hash_s; // hash_c implements the H_c operation in PMBTokens. It returns one on success // and zero on error. hash_c_func_t hash_c; int prefix_point : 1; } PMBTOKEN_METHOD; static const uint8_t kDefaultAdditionalData[32] = {0}; static int pmbtoken_init_method(PMBTOKEN_METHOD *method, int curve_nid, const uint8_t *h_bytes, size_t h_len, hash_t_func_t hash_t, hash_s_func_t hash_s, hash_c_func_t hash_c, int prefix_point) { method->group = EC_GROUP_new_by_curve_name(curve_nid); if (method->group == NULL) { return 0; } method->hash_t = hash_t; method->hash_s = hash_s; method->hash_c = hash_c; method->prefix_point = prefix_point; EC_AFFINE h; if (!ec_point_from_uncompressed(method->group, &h, h_bytes, h_len)) { return 0; } ec_affine_to_jacobian(method->group, &method->h, &h); if (!ec_init_precomp(method->group, &method->g_precomp, &method->group->generator->raw) || !ec_init_precomp(method->group, &method->h_precomp, &method->h)) { return 0; } return 1; } // generate_keypair generates a keypair for the PMBTokens construction. // |out_x| and |out_y| are set to the secret half of the keypair, while // |*out_pub| is set to the public half of the keypair. It returns one on // success and zero on failure. static int generate_keypair(const PMBTOKEN_METHOD *method, EC_SCALAR *out_x, EC_SCALAR *out_y, EC_RAW_POINT *out_pub) { if (!ec_random_nonzero_scalar(method->group, out_x, kDefaultAdditionalData) || !ec_random_nonzero_scalar(method->group, out_y, kDefaultAdditionalData) || !ec_point_mul_scalar_precomp(method->group, out_pub, &method->g_precomp, out_x, &method->h_precomp, out_y, NULL, NULL)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_MALLOC_FAILURE); return 0; } return 1; } static int point_to_cbb(CBB *out, const EC_GROUP *group, const EC_AFFINE *point) { size_t len = ec_point_to_bytes(group, point, POINT_CONVERSION_UNCOMPRESSED, NULL, 0); if (len == 0) { return 0; } uint8_t *p; return CBB_add_space(out, &p, len) && ec_point_to_bytes(group, point, POINT_CONVERSION_UNCOMPRESSED, p, len) == len; } static int cbb_add_prefixed_point(CBB *out, const EC_GROUP *group, const EC_AFFINE *point, int prefix_point) { if (prefix_point) { CBB child; if (!CBB_add_u16_length_prefixed(out, &child) || !point_to_cbb(&child, group, point) || !CBB_flush(out)) { return 0; } } else { if (!point_to_cbb(out, group, point) || !CBB_flush(out)) { return 0; } } return 1; } static int cbs_get_prefixed_point(CBS *cbs, const EC_GROUP *group, EC_AFFINE *out, int prefix_point) { CBS child; if (prefix_point) { if (!CBS_get_u16_length_prefixed(cbs, &child)) { return 0; } } else { size_t plen = 1 + 2 * BN_num_bytes(&group->field); if (!CBS_get_bytes(cbs, &child, plen)) { return 0; } } if (!ec_point_from_uncompressed(group, out, CBS_data(&child), CBS_len(&child))) { return 0; } return 1; } static int mul_public_3(const EC_GROUP *group, EC_RAW_POINT *out, const EC_RAW_POINT *p0, const EC_SCALAR *scalar0, const EC_RAW_POINT *p1, const EC_SCALAR *scalar1, const EC_RAW_POINT *p2, const EC_SCALAR *scalar2) { EC_RAW_POINT points[3] = {*p0, *p1, *p2}; EC_SCALAR scalars[3] = {*scalar0, *scalar1, *scalar2}; return ec_point_mul_scalar_public_batch(group, out, /*g_scalar=*/NULL, points, scalars, 3); } static int pmbtoken_generate_key(const PMBTOKEN_METHOD *method, CBB *out_private, CBB *out_public) { const EC_GROUP *group = method->group; EC_RAW_POINT pub[3]; EC_SCALAR x0, y0, x1, y1, xs, ys; if (!generate_keypair(method, &x0, &y0, &pub[0]) || !generate_keypair(method, &x1, &y1, &pub[1]) || !generate_keypair(method, &xs, &ys, &pub[2])) { OPENSSL_PUT_ERROR(TRUST_TOKEN, TRUST_TOKEN_R_KEYGEN_FAILURE); return 0; } const EC_SCALAR *scalars[] = {&x0, &y0, &x1, &y1, &xs, &ys}; size_t scalar_len = BN_num_bytes(&group->order); for (size_t i = 0; i < OPENSSL_ARRAY_SIZE(scalars); i++) { uint8_t *buf; if (!CBB_add_space(out_private, &buf, scalar_len)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, TRUST_TOKEN_R_BUFFER_TOO_SMALL); return 0; } ec_scalar_to_bytes(group, buf, &scalar_len, scalars[i]); } EC_AFFINE pub_affine[3]; if (!ec_jacobian_to_affine_batch(group, pub_affine, pub, 3)) { return 0; } if (!cbb_add_prefixed_point(out_public, group, &pub_affine[0], method->prefix_point) || !cbb_add_prefixed_point(out_public, group, &pub_affine[1], method->prefix_point) || !cbb_add_prefixed_point(out_public, group, &pub_affine[2], method->prefix_point)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, TRUST_TOKEN_R_BUFFER_TOO_SMALL); return 0; } return 1; } static int pmbtoken_client_key_from_bytes(const PMBTOKEN_METHOD *method, TRUST_TOKEN_CLIENT_KEY *key, const uint8_t *in, size_t len) { CBS cbs; CBS_init(&cbs, in, len); if (!cbs_get_prefixed_point(&cbs, method->group, &key->pub0, method->prefix_point) || !cbs_get_prefixed_point(&cbs, method->group, &key->pub1, method->prefix_point) || !cbs_get_prefixed_point(&cbs, method->group, &key->pubs, method->prefix_point) || CBS_len(&cbs) != 0) { OPENSSL_PUT_ERROR(TRUST_TOKEN, TRUST_TOKEN_R_DECODE_FAILURE); return 0; } return 1; } static int pmbtoken_issuer_key_from_bytes(const PMBTOKEN_METHOD *method, TRUST_TOKEN_ISSUER_KEY *key, const uint8_t *in, size_t len) { const EC_GROUP *group = method->group; CBS cbs, tmp; CBS_init(&cbs, in, len); size_t scalar_len = BN_num_bytes(&group->order); EC_SCALAR *scalars[] = {&key->x0, &key->y0, &key->x1, &key->y1, &key->xs, &key->ys}; for (size_t i = 0; i < OPENSSL_ARRAY_SIZE(scalars); i++) { if (!CBS_get_bytes(&cbs, &tmp, scalar_len) || !ec_scalar_from_bytes(group, scalars[i], CBS_data(&tmp), CBS_len(&tmp))) { OPENSSL_PUT_ERROR(TRUST_TOKEN, TRUST_TOKEN_R_DECODE_FAILURE); return 0; } } // Recompute the public key. EC_RAW_POINT pub[3]; EC_AFFINE pub_affine[3]; if (!ec_point_mul_scalar_precomp(group, &pub[0], &method->g_precomp, &key->x0, &method->h_precomp, &key->y0, NULL, NULL) || !ec_init_precomp(group, &key->pub0_precomp, &pub[0]) || !ec_point_mul_scalar_precomp(group, &pub[1], &method->g_precomp, &key->x1, &method->h_precomp, &key->y1, NULL, NULL) || !ec_init_precomp(group, &key->pub1_precomp, &pub[1]) || !ec_point_mul_scalar_precomp(group, &pub[2], &method->g_precomp, &key->xs, &method->h_precomp, &key->ys, NULL, NULL) || !ec_init_precomp(group, &key->pubs_precomp, &pub[2]) || !ec_jacobian_to_affine_batch(group, pub_affine, pub, 3)) { return 0; } key->pub0 = pub_affine[0]; key->pub1 = pub_affine[1]; key->pubs = pub_affine[2]; return 1; } static STACK_OF(TRUST_TOKEN_PRETOKEN) * pmbtoken_blind(const PMBTOKEN_METHOD *method, CBB *cbb, size_t count) { const EC_GROUP *group = method->group; STACK_OF(TRUST_TOKEN_PRETOKEN) *pretokens = sk_TRUST_TOKEN_PRETOKEN_new_null(); if (pretokens == NULL) { OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_MALLOC_FAILURE); goto err; } for (size_t i = 0; i < count; i++) { // Insert |pretoken| into |pretokens| early to simplify error-handling. TRUST_TOKEN_PRETOKEN *pretoken = OPENSSL_malloc(sizeof(TRUST_TOKEN_PRETOKEN)); if (pretoken == NULL || !sk_TRUST_TOKEN_PRETOKEN_push(pretokens, pretoken)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_MALLOC_FAILURE); TRUST_TOKEN_PRETOKEN_free(pretoken); goto err; } RAND_bytes(pretoken->t, sizeof(pretoken->t)); // We sample |pretoken->r| in Montgomery form to simplify inverting. if (!ec_random_nonzero_scalar(group, &pretoken->r, kDefaultAdditionalData)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_MALLOC_FAILURE); goto err; } EC_SCALAR rinv; ec_scalar_inv0_montgomery(group, &rinv, &pretoken->r); // Convert both out of Montgomery form. ec_scalar_from_montgomery(group, &pretoken->r, &pretoken->r); ec_scalar_from_montgomery(group, &rinv, &rinv); EC_RAW_POINT T, Tp; if (!method->hash_t(group, &T, pretoken->t) || !ec_point_mul_scalar(group, &Tp, &T, &rinv) || !ec_jacobian_to_affine(group, &pretoken->Tp, &Tp)) { goto err; } if (!cbb_add_prefixed_point(cbb, group, &pretoken->Tp, method->prefix_point)) { goto err; } } return pretokens; err: sk_TRUST_TOKEN_PRETOKEN_pop_free(pretokens, TRUST_TOKEN_PRETOKEN_free); return NULL; } static int scalar_to_cbb(CBB *out, const EC_GROUP *group, const EC_SCALAR *scalar) { uint8_t *buf; size_t scalar_len = BN_num_bytes(&group->order); if (!CBB_add_space(out, &buf, scalar_len)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_MALLOC_FAILURE); return 0; } ec_scalar_to_bytes(group, buf, &scalar_len, scalar); return 1; } static int scalar_from_cbs(CBS *cbs, const EC_GROUP *group, EC_SCALAR *out) { size_t scalar_len = BN_num_bytes(&group->order); CBS tmp; if (!CBS_get_bytes(cbs, &tmp, scalar_len)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, TRUST_TOKEN_R_DECODE_FAILURE); return 0; } ec_scalar_from_bytes(group, out, CBS_data(&tmp), CBS_len(&tmp)); return 1; } static int hash_c_dleq(const PMBTOKEN_METHOD *method, EC_SCALAR *out, const EC_AFFINE *X, const EC_AFFINE *T, const EC_AFFINE *S, const EC_AFFINE *W, const EC_AFFINE *K0, const EC_AFFINE *K1) { static const uint8_t kDLEQ2Label[] = "DLEQ2"; int ok = 0; CBB cbb; CBB_zero(&cbb); uint8_t *buf = NULL; size_t len; if (!CBB_init(&cbb, 0) || !CBB_add_bytes(&cbb, kDLEQ2Label, sizeof(kDLEQ2Label)) || !point_to_cbb(&cbb, method->group, X) || !point_to_cbb(&cbb, method->group, T) || !point_to_cbb(&cbb, method->group, S) || !point_to_cbb(&cbb, method->group, W) || !point_to_cbb(&cbb, method->group, K0) || !point_to_cbb(&cbb, method->group, K1) || !CBB_finish(&cbb, &buf, &len) || !method->hash_c(method->group, out, buf, len)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_MALLOC_FAILURE); goto err; } ok = 1; err: CBB_cleanup(&cbb); OPENSSL_free(buf); return ok; } static int hash_c_dleqor(const PMBTOKEN_METHOD *method, EC_SCALAR *out, const EC_AFFINE *X0, const EC_AFFINE *X1, const EC_AFFINE *T, const EC_AFFINE *S, const EC_AFFINE *W, const EC_AFFINE *K00, const EC_AFFINE *K01, const EC_AFFINE *K10, const EC_AFFINE *K11) { static const uint8_t kDLEQOR2Label[] = "DLEQOR2"; int ok = 0; CBB cbb; CBB_zero(&cbb); uint8_t *buf = NULL; size_t len; if (!CBB_init(&cbb, 0) || !CBB_add_bytes(&cbb, kDLEQOR2Label, sizeof(kDLEQOR2Label)) || !point_to_cbb(&cbb, method->group, X0) || !point_to_cbb(&cbb, method->group, X1) || !point_to_cbb(&cbb, method->group, T) || !point_to_cbb(&cbb, method->group, S) || !point_to_cbb(&cbb, method->group, W) || !point_to_cbb(&cbb, method->group, K00) || !point_to_cbb(&cbb, method->group, K01) || !point_to_cbb(&cbb, method->group, K10) || !point_to_cbb(&cbb, method->group, K11) || !CBB_finish(&cbb, &buf, &len) || !method->hash_c(method->group, out, buf, len)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_MALLOC_FAILURE); goto err; } ok = 1; err: CBB_cleanup(&cbb); OPENSSL_free(buf); return ok; } static int hash_c_batch(const PMBTOKEN_METHOD *method, EC_SCALAR *out, const CBB *points, size_t index) { static const uint8_t kDLEQBatchLabel[] = "DLEQ BATCH"; if (index > 0xffff) { // The protocol supports only two-byte batches. OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_OVERFLOW); return 0; } int ok = 0; CBB cbb; CBB_zero(&cbb); uint8_t *buf = NULL; size_t len; if (!CBB_init(&cbb, 0) || !CBB_add_bytes(&cbb, kDLEQBatchLabel, sizeof(kDLEQBatchLabel)) || !CBB_add_bytes(&cbb, CBB_data(points), CBB_len(points)) || !CBB_add_u16(&cbb, (uint16_t)index) || !CBB_finish(&cbb, &buf, &len) || !method->hash_c(method->group, out, buf, len)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_MALLOC_FAILURE); goto err; } ok = 1; err: CBB_cleanup(&cbb); OPENSSL_free(buf); return ok; } // The DLEQ2 and DLEQOR2 constructions are described in appendix B of // https://eprint.iacr.org/2020/072/20200324:214215. DLEQ2 is an instance of // DLEQOR2 with only one value (n=1). static int dleq_generate(const PMBTOKEN_METHOD *method, CBB *cbb, const TRUST_TOKEN_ISSUER_KEY *priv, const EC_RAW_POINT *T, const EC_RAW_POINT *S, const EC_RAW_POINT *W, const EC_RAW_POINT *Ws, uint8_t private_metadata) { const EC_GROUP *group = method->group; // We generate a DLEQ proof for the validity token and a DLEQOR2 proof for the // private metadata token. To allow amortizing Jacobian-to-affine conversions, // we compute Ki for both proofs first. enum { idx_T, idx_S, idx_W, idx_Ws, idx_Ks0, idx_Ks1, idx_Kb0, idx_Kb1, idx_Ko0, idx_Ko1, num_idx, }; EC_RAW_POINT jacobians[num_idx]; // Setup the DLEQ proof. EC_SCALAR ks0, ks1; if (// ks0, ks1 <- Zp !ec_random_nonzero_scalar(group, &ks0, kDefaultAdditionalData) || !ec_random_nonzero_scalar(group, &ks1, kDefaultAdditionalData) || // Ks = ks0*(G;T) + ks1*(H;S) !ec_point_mul_scalar_precomp(group, &jacobians[idx_Ks0], &method->g_precomp, &ks0, &method->h_precomp, &ks1, NULL, NULL) || !ec_point_mul_scalar_batch(group, &jacobians[idx_Ks1], T, &ks0, S, &ks1, NULL, NULL)) { return 0; } // Setup the DLEQOR proof. First, select values of xb, yb (keys corresponding // to the private metadata value) and pubo (public key corresponding to the // other value) in constant time. BN_ULONG mask = ((BN_ULONG)0) - (private_metadata & 1); EC_PRECOMP pubo_precomp; EC_SCALAR xb, yb; ec_scalar_select(group, &xb, mask, &priv->x1, &priv->x0); ec_scalar_select(group, &yb, mask, &priv->y1, &priv->y0); ec_precomp_select(group, &pubo_precomp, mask, &priv->pub0_precomp, &priv->pub1_precomp); EC_SCALAR k0, k1, minus_co, uo, vo; if (// k0, k1 <- Zp !ec_random_nonzero_scalar(group, &k0, kDefaultAdditionalData) || !ec_random_nonzero_scalar(group, &k1, kDefaultAdditionalData) || // Kb = k0*(G;T) + k1*(H;S) !ec_point_mul_scalar_precomp(group, &jacobians[idx_Kb0], &method->g_precomp, &k0, &method->h_precomp, &k1, NULL, NULL) || !ec_point_mul_scalar_batch(group, &jacobians[idx_Kb1], T, &k0, S, &k1, NULL, NULL) || // co, uo, vo <- Zp !ec_random_nonzero_scalar(group, &minus_co, kDefaultAdditionalData) || !ec_random_nonzero_scalar(group, &uo, kDefaultAdditionalData) || !ec_random_nonzero_scalar(group, &vo, kDefaultAdditionalData) || // Ko = uo*(G;T) + vo*(H;S) - co*(pubo;W) !ec_point_mul_scalar_precomp(group, &jacobians[idx_Ko0], &method->g_precomp, &uo, &method->h_precomp, &vo, &pubo_precomp, &minus_co) || !ec_point_mul_scalar_batch(group, &jacobians[idx_Ko1], T, &uo, S, &vo, W, &minus_co)) { return 0; } EC_AFFINE affines[num_idx]; jacobians[idx_T] = *T; jacobians[idx_S] = *S; jacobians[idx_W] = *W; jacobians[idx_Ws] = *Ws; if (!ec_jacobian_to_affine_batch(group, affines, jacobians, num_idx)) { return 0; } // Select the K corresponding to K0 and K1 in constant-time. EC_AFFINE K00, K01, K10, K11; ec_affine_select(group, &K00, mask, &affines[idx_Ko0], &affines[idx_Kb0]); ec_affine_select(group, &K01, mask, &affines[idx_Ko1], &affines[idx_Kb1]); ec_affine_select(group, &K10, mask, &affines[idx_Kb0], &affines[idx_Ko0]); ec_affine_select(group, &K11, mask, &affines[idx_Kb1], &affines[idx_Ko1]); // Compute c = Hc(...) for the two proofs. EC_SCALAR cs, c; if (!hash_c_dleq(method, &cs, &priv->pubs, &affines[idx_T], &affines[idx_S], &affines[idx_Ws], &affines[idx_Ks0], &affines[idx_Ks1]) || !hash_c_dleqor(method, &c, &priv->pub0, &priv->pub1, &affines[idx_T], &affines[idx_S], &affines[idx_W], &K00, &K01, &K10, &K11)) { return 0; } // Compute cb, ub, and ub for the two proofs. In each of these products, only // one operand is in Montgomery form, so the product does not need to be // converted. EC_SCALAR cs_mont; ec_scalar_to_montgomery(group, &cs_mont, &cs); // us = ks0 + cs*xs EC_SCALAR us, vs; ec_scalar_mul_montgomery(group, &us, &priv->xs, &cs_mont); ec_scalar_add(group, &us, &ks0, &us); // vs = ks1 + cs*ys ec_scalar_mul_montgomery(group, &vs, &priv->ys, &cs_mont); ec_scalar_add(group, &vs, &ks1, &vs); // Store DLEQ2 proof in transcript. if (!scalar_to_cbb(cbb, group, &cs) || !scalar_to_cbb(cbb, group, &us) || !scalar_to_cbb(cbb, group, &vs)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_MALLOC_FAILURE); return 0; } // cb = c - co EC_SCALAR cb, ub, vb; ec_scalar_add(group, &cb, &c, &minus_co); EC_SCALAR cb_mont; ec_scalar_to_montgomery(group, &cb_mont, &cb); // ub = k0 + cb*xb ec_scalar_mul_montgomery(group, &ub, &xb, &cb_mont); ec_scalar_add(group, &ub, &k0, &ub); // vb = k1 + cb*yb ec_scalar_mul_montgomery(group, &vb, &yb, &cb_mont); ec_scalar_add(group, &vb, &k1, &vb); // Select c, u, v in constant-time. EC_SCALAR co, c0, c1, u0, u1, v0, v1; ec_scalar_neg(group, &co, &minus_co); ec_scalar_select(group, &c0, mask, &co, &cb); ec_scalar_select(group, &u0, mask, &uo, &ub); ec_scalar_select(group, &v0, mask, &vo, &vb); ec_scalar_select(group, &c1, mask, &cb, &co); ec_scalar_select(group, &u1, mask, &ub, &uo); ec_scalar_select(group, &v1, mask, &vb, &vo); // Store DLEQOR2 proof in transcript. if (!scalar_to_cbb(cbb, group, &c0) || !scalar_to_cbb(cbb, group, &c1) || !scalar_to_cbb(cbb, group, &u0) || !scalar_to_cbb(cbb, group, &u1) || !scalar_to_cbb(cbb, group, &v0) || !scalar_to_cbb(cbb, group, &v1)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_MALLOC_FAILURE); return 0; } return 1; } static int dleq_verify(const PMBTOKEN_METHOD *method, CBS *cbs, const TRUST_TOKEN_CLIENT_KEY *pub, const EC_RAW_POINT *T, const EC_RAW_POINT *S, const EC_RAW_POINT *W, const EC_RAW_POINT *Ws) { const EC_GROUP *group = method->group; const EC_RAW_POINT *g = &group->generator->raw; // We verify a DLEQ proof for the validity token and a DLEQOR2 proof for the // private metadata token. To allow amortizing Jacobian-to-affine conversions, // we compute Ki for both proofs first. Additionally, all inputs to this // function are public, so we can use the faster variable-time // multiplications. enum { idx_T, idx_S, idx_W, idx_Ws, idx_Ks0, idx_Ks1, idx_K00, idx_K01, idx_K10, idx_K11, num_idx, }; EC_RAW_POINT jacobians[num_idx]; // Decode the DLEQ proof. EC_SCALAR cs, us, vs; if (!scalar_from_cbs(cbs, group, &cs) || !scalar_from_cbs(cbs, group, &us) || !scalar_from_cbs(cbs, group, &vs)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, TRUST_TOKEN_R_DECODE_FAILURE); return 0; } // Ks = us*(G;T) + vs*(H;S) - cs*(pubs;Ws) EC_RAW_POINT pubs; ec_affine_to_jacobian(group, &pubs, &pub->pubs); EC_SCALAR minus_cs; ec_scalar_neg(group, &minus_cs, &cs); if (!mul_public_3(group, &jacobians[idx_Ks0], g, &us, &method->h, &vs, &pubs, &minus_cs) || !mul_public_3(group, &jacobians[idx_Ks1], T, &us, S, &vs, Ws, &minus_cs)) { return 0; } // Decode the DLEQOR proof. EC_SCALAR c0, c1, u0, u1, v0, v1; if (!scalar_from_cbs(cbs, group, &c0) || !scalar_from_cbs(cbs, group, &c1) || !scalar_from_cbs(cbs, group, &u0) || !scalar_from_cbs(cbs, group, &u1) || !scalar_from_cbs(cbs, group, &v0) || !scalar_from_cbs(cbs, group, &v1)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, TRUST_TOKEN_R_DECODE_FAILURE); return 0; } EC_RAW_POINT pub0, pub1; ec_affine_to_jacobian(group, &pub0, &pub->pub0); ec_affine_to_jacobian(group, &pub1, &pub->pub1); EC_SCALAR minus_c0, minus_c1; ec_scalar_neg(group, &minus_c0, &c0); ec_scalar_neg(group, &minus_c1, &c1); if (// K0 = u0*(G;T) + v0*(H;S) - c0*(pub0;W) !mul_public_3(group, &jacobians[idx_K00], g, &u0, &method->h, &v0, &pub0, &minus_c0) || !mul_public_3(group, &jacobians[idx_K01], T, &u0, S, &v0, W, &minus_c0) || // K1 = u1*(G;T) + v1*(H;S) - c1*(pub1;W) !mul_public_3(group, &jacobians[idx_K10], g, &u1, &method->h, &v1, &pub1, &minus_c1) || !mul_public_3(group, &jacobians[idx_K11], T, &u1, S, &v1, W, &minus_c1)) { return 0; } EC_AFFINE affines[num_idx]; jacobians[idx_T] = *T; jacobians[idx_S] = *S; jacobians[idx_W] = *W; jacobians[idx_Ws] = *Ws; if (!ec_jacobian_to_affine_batch(group, affines, jacobians, num_idx)) { return 0; } // Check the DLEQ proof. EC_SCALAR calculated; if (!hash_c_dleq(method, &calculated, &pub->pubs, &affines[idx_T], &affines[idx_S], &affines[idx_Ws], &affines[idx_Ks0], &affines[idx_Ks1])) { return 0; } // cs == calculated if (!ec_scalar_equal_vartime(group, &cs, &calculated)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, TRUST_TOKEN_R_INVALID_PROOF); return 0; } // Check the DLEQOR proof. if (!hash_c_dleqor(method, &calculated, &pub->pub0, &pub->pub1, &affines[idx_T], &affines[idx_S], &affines[idx_W], &affines[idx_K00], &affines[idx_K01], &affines[idx_K10], &affines[idx_K11])) { return 0; } // c0 + c1 == calculated EC_SCALAR c; ec_scalar_add(group, &c, &c0, &c1); if (!ec_scalar_equal_vartime(group, &c, &calculated)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, TRUST_TOKEN_R_INVALID_PROOF); return 0; } return 1; } static int pmbtoken_sign(const PMBTOKEN_METHOD *method, const TRUST_TOKEN_ISSUER_KEY *key, CBB *cbb, CBS *cbs, size_t num_requested, size_t num_to_issue, uint8_t private_metadata) { const EC_GROUP *group = method->group; if (num_requested < num_to_issue) { OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_INTERNAL_ERROR); return 0; } if (num_to_issue > ((size_t)-1) / sizeof(EC_RAW_POINT) || num_to_issue > ((size_t)-1) / sizeof(EC_SCALAR)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_OVERFLOW); return 0; } int ret = 0; EC_RAW_POINT *Tps = OPENSSL_malloc(num_to_issue * sizeof(EC_RAW_POINT)); EC_RAW_POINT *Sps = OPENSSL_malloc(num_to_issue * sizeof(EC_RAW_POINT)); EC_RAW_POINT *Wps = OPENSSL_malloc(num_to_issue * sizeof(EC_RAW_POINT)); EC_RAW_POINT *Wsps = OPENSSL_malloc(num_to_issue * sizeof(EC_RAW_POINT)); EC_SCALAR *es = OPENSSL_malloc(num_to_issue * sizeof(EC_SCALAR)); CBB batch_cbb; CBB_zero(&batch_cbb); if (!Tps || !Sps || !Wps || !Wsps || !es || !CBB_init(&batch_cbb, 0) || !point_to_cbb(&batch_cbb, method->group, &key->pubs) || !point_to_cbb(&batch_cbb, method->group, &key->pub0) || !point_to_cbb(&batch_cbb, method->group, &key->pub1)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_MALLOC_FAILURE); goto err; } for (size_t i = 0; i < num_to_issue; i++) { EC_AFFINE Tp_affine; EC_RAW_POINT Tp; if (!cbs_get_prefixed_point(cbs, group, &Tp_affine, method->prefix_point)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, TRUST_TOKEN_R_DECODE_FAILURE); goto err; } ec_affine_to_jacobian(group, &Tp, &Tp_affine); EC_SCALAR xb, yb; BN_ULONG mask = ((BN_ULONG)0) - (private_metadata & 1); ec_scalar_select(group, &xb, mask, &key->x1, &key->x0); ec_scalar_select(group, &yb, mask, &key->y1, &key->y0); uint8_t s[TRUST_TOKEN_NONCE_SIZE]; RAND_bytes(s, TRUST_TOKEN_NONCE_SIZE); // The |jacobians| and |affines| contain Sp, Wp, and Wsp. EC_RAW_POINT jacobians[3]; EC_AFFINE affines[3]; if (!method->hash_s(group, &jacobians[0], &Tp_affine, s) || !ec_point_mul_scalar_batch(group, &jacobians[1], &Tp, &xb, &jacobians[0], &yb, NULL, NULL) || !ec_point_mul_scalar_batch(group, &jacobians[2], &Tp, &key->xs, &jacobians[0], &key->ys, NULL, NULL) || !ec_jacobian_to_affine_batch(group, affines, jacobians, 3) || !CBB_add_bytes(cbb, s, TRUST_TOKEN_NONCE_SIZE) || !cbb_add_prefixed_point(cbb, group, &affines[1], method->prefix_point) || !cbb_add_prefixed_point(cbb, group, &affines[2], method->prefix_point)) { goto err; } if (!point_to_cbb(&batch_cbb, group, &Tp_affine) || !point_to_cbb(&batch_cbb, group, &affines[0]) || !point_to_cbb(&batch_cbb, group, &affines[1]) || !point_to_cbb(&batch_cbb, group, &affines[2])) { OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_MALLOC_FAILURE); goto err; } Tps[i] = Tp; Sps[i] = jacobians[0]; Wps[i] = jacobians[1]; Wsps[i] = jacobians[2]; if (!CBB_flush(cbb)) { goto err; } } // The DLEQ batching construction is described in appendix B of // https://eprint.iacr.org/2020/072/20200324:214215. Note the additional // computations all act on public inputs. for (size_t i = 0; i < num_to_issue; i++) { if (!hash_c_batch(method, &es[i], &batch_cbb, i)) { goto err; } } EC_RAW_POINT Tp_batch, Sp_batch, Wp_batch, Wsp_batch; if (!ec_point_mul_scalar_public_batch(group, &Tp_batch, /*g_scalar=*/NULL, Tps, es, num_to_issue) || !ec_point_mul_scalar_public_batch(group, &Sp_batch, /*g_scalar=*/NULL, Sps, es, num_to_issue) || !ec_point_mul_scalar_public_batch(group, &Wp_batch, /*g_scalar=*/NULL, Wps, es, num_to_issue) || !ec_point_mul_scalar_public_batch(group, &Wsp_batch, /*g_scalar=*/NULL, Wsps, es, num_to_issue)) { goto err; } CBB proof; if (!CBB_add_u16_length_prefixed(cbb, &proof) || !dleq_generate(method, &proof, key, &Tp_batch, &Sp_batch, &Wp_batch, &Wsp_batch, private_metadata) || !CBB_flush(cbb)) { goto err; } // Skip over any unused requests. size_t point_len = 1 + 2 * BN_num_bytes(&group->field); size_t token_len = point_len; if (method->prefix_point) { token_len += 2; } if (!CBS_skip(cbs, token_len * (num_requested - num_to_issue))) { OPENSSL_PUT_ERROR(TRUST_TOKEN, TRUST_TOKEN_R_DECODE_FAILURE); goto err; } ret = 1; err: OPENSSL_free(Tps); OPENSSL_free(Sps); OPENSSL_free(Wps); OPENSSL_free(Wsps); OPENSSL_free(es); CBB_cleanup(&batch_cbb); return ret; } static STACK_OF(TRUST_TOKEN) * pmbtoken_unblind(const PMBTOKEN_METHOD *method, const TRUST_TOKEN_CLIENT_KEY *key, const STACK_OF(TRUST_TOKEN_PRETOKEN) * pretokens, CBS *cbs, size_t count, uint32_t key_id) { const EC_GROUP *group = method->group; if (count > sk_TRUST_TOKEN_PRETOKEN_num(pretokens)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, TRUST_TOKEN_R_DECODE_FAILURE); return NULL; } int ok = 0; STACK_OF(TRUST_TOKEN) *ret = sk_TRUST_TOKEN_new_null(); if (ret == NULL) { OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_MALLOC_FAILURE); return NULL; } if (count > ((size_t)-1) / sizeof(EC_RAW_POINT) || count > ((size_t)-1) / sizeof(EC_SCALAR)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_OVERFLOW); return 0; } EC_RAW_POINT *Tps = OPENSSL_malloc(count * sizeof(EC_RAW_POINT)); EC_RAW_POINT *Sps = OPENSSL_malloc(count * sizeof(EC_RAW_POINT)); EC_RAW_POINT *Wps = OPENSSL_malloc(count * sizeof(EC_RAW_POINT)); EC_RAW_POINT *Wsps = OPENSSL_malloc(count * sizeof(EC_RAW_POINT)); EC_SCALAR *es = OPENSSL_malloc(count * sizeof(EC_SCALAR)); CBB batch_cbb; CBB_zero(&batch_cbb); if (!Tps || !Sps || !Wps || !Wsps || !es || !CBB_init(&batch_cbb, 0) || !point_to_cbb(&batch_cbb, method->group, &key->pubs) || !point_to_cbb(&batch_cbb, method->group, &key->pub0) || !point_to_cbb(&batch_cbb, method->group, &key->pub1)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_MALLOC_FAILURE); goto err; } for (size_t i = 0; i < count; i++) { const TRUST_TOKEN_PRETOKEN *pretoken = sk_TRUST_TOKEN_PRETOKEN_value(pretokens, i); uint8_t s[TRUST_TOKEN_NONCE_SIZE]; EC_AFFINE Wp_affine, Wsp_affine; if (!CBS_copy_bytes(cbs, s, TRUST_TOKEN_NONCE_SIZE) || !cbs_get_prefixed_point(cbs, group, &Wp_affine, method->prefix_point) || !cbs_get_prefixed_point(cbs, group, &Wsp_affine, method->prefix_point)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, TRUST_TOKEN_R_DECODE_FAILURE); goto err; } ec_affine_to_jacobian(group, &Tps[i], &pretoken->Tp); ec_affine_to_jacobian(group, &Wps[i], &Wp_affine); ec_affine_to_jacobian(group, &Wsps[i], &Wsp_affine); if (!method->hash_s(group, &Sps[i], &pretoken->Tp, s)) { goto err; } EC_AFFINE Sp_affine; if (!point_to_cbb(&batch_cbb, group, &pretoken->Tp) || !ec_jacobian_to_affine(group, &Sp_affine, &Sps[i]) || !point_to_cbb(&batch_cbb, group, &Sp_affine) || !point_to_cbb(&batch_cbb, group, &Wp_affine) || !point_to_cbb(&batch_cbb, group, &Wsp_affine)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_MALLOC_FAILURE); goto err; } // Unblind the token. EC_RAW_POINT jacobians[3]; EC_AFFINE affines[3]; if (!ec_point_mul_scalar(group, &jacobians[0], &Sps[i], &pretoken->r) || !ec_point_mul_scalar(group, &jacobians[1], &Wps[i], &pretoken->r) || !ec_point_mul_scalar(group, &jacobians[2], &Wsps[i], &pretoken->r) || !ec_jacobian_to_affine_batch(group, affines, jacobians, 3)) { goto err; } // Serialize the token. Include |key_id| to avoid an extra copy in the layer // above. CBB token_cbb; size_t point_len = 1 + 2 * BN_num_bytes(&group->field); if (!CBB_init(&token_cbb, 4 + TRUST_TOKEN_NONCE_SIZE + 3 * (2 + point_len)) || !CBB_add_u32(&token_cbb, key_id) || !CBB_add_bytes(&token_cbb, pretoken->t, TRUST_TOKEN_NONCE_SIZE) || !cbb_add_prefixed_point(&token_cbb, group, &affines[0], method->prefix_point) || !cbb_add_prefixed_point(&token_cbb, group, &affines[1], method->prefix_point) || !cbb_add_prefixed_point(&token_cbb, group, &affines[2], method->prefix_point) || !CBB_flush(&token_cbb)) { CBB_cleanup(&token_cbb); goto err; } TRUST_TOKEN *token = TRUST_TOKEN_new(CBB_data(&token_cbb), CBB_len(&token_cbb)); CBB_cleanup(&token_cbb); if (token == NULL || !sk_TRUST_TOKEN_push(ret, token)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_MALLOC_FAILURE); TRUST_TOKEN_free(token); goto err; } } // The DLEQ batching construction is described in appendix B of // https://eprint.iacr.org/2020/072/20200324:214215. Note the additional // computations all act on public inputs. for (size_t i = 0; i < count; i++) { if (!hash_c_batch(method, &es[i], &batch_cbb, i)) { goto err; } } EC_RAW_POINT Tp_batch, Sp_batch, Wp_batch, Wsp_batch; if (!ec_point_mul_scalar_public_batch(group, &Tp_batch, /*g_scalar=*/NULL, Tps, es, count) || !ec_point_mul_scalar_public_batch(group, &Sp_batch, /*g_scalar=*/NULL, Sps, es, count) || !ec_point_mul_scalar_public_batch(group, &Wp_batch, /*g_scalar=*/NULL, Wps, es, count) || !ec_point_mul_scalar_public_batch(group, &Wsp_batch, /*g_scalar=*/NULL, Wsps, es, count)) { goto err; } CBS proof; if (!CBS_get_u16_length_prefixed(cbs, &proof) || !dleq_verify(method, &proof, key, &Tp_batch, &Sp_batch, &Wp_batch, &Wsp_batch) || CBS_len(&proof) != 0) { goto err; } ok = 1; err: OPENSSL_free(Tps); OPENSSL_free(Sps); OPENSSL_free(Wps); OPENSSL_free(Wsps); OPENSSL_free(es); CBB_cleanup(&batch_cbb); if (!ok) { sk_TRUST_TOKEN_pop_free(ret, TRUST_TOKEN_free); ret = NULL; } return ret; } static int pmbtoken_read(const PMBTOKEN_METHOD *method, const TRUST_TOKEN_ISSUER_KEY *key, uint8_t out_nonce[TRUST_TOKEN_NONCE_SIZE], uint8_t *out_private_metadata, const uint8_t *token, size_t token_len) { const EC_GROUP *group = method->group; CBS cbs; CBS_init(&cbs, token, token_len); EC_AFFINE S, W, Ws; if (!CBS_copy_bytes(&cbs, out_nonce, TRUST_TOKEN_NONCE_SIZE) || !cbs_get_prefixed_point(&cbs, group, &S, method->prefix_point) || !cbs_get_prefixed_point(&cbs, group, &W, method->prefix_point) || !cbs_get_prefixed_point(&cbs, group, &Ws, method->prefix_point) || CBS_len(&cbs) != 0) { OPENSSL_PUT_ERROR(TRUST_TOKEN, TRUST_TOKEN_R_INVALID_TOKEN); return 0; } EC_RAW_POINT T; if (!method->hash_t(group, &T, out_nonce)) { return 0; } // We perform three multiplications with S and T. This is enough that it is // worth using |ec_point_mul_scalar_precomp|. EC_RAW_POINT S_jacobian; EC_PRECOMP S_precomp, T_precomp; ec_affine_to_jacobian(group, &S_jacobian, &S); if (!ec_init_precomp(group, &S_precomp, &S_jacobian) || !ec_init_precomp(group, &T_precomp, &T)) { return 0; } EC_RAW_POINT Ws_calculated; // Check the validity of the token. if (!ec_point_mul_scalar_precomp(group, &Ws_calculated, &T_precomp, &key->xs, &S_precomp, &key->ys, NULL, NULL) || !ec_affine_jacobian_equal(group, &Ws, &Ws_calculated)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, TRUST_TOKEN_R_BAD_VALIDITY_CHECK); return 0; } EC_RAW_POINT W0, W1; if (!ec_point_mul_scalar_precomp(group, &W0, &T_precomp, &key->x0, &S_precomp, &key->y0, NULL, NULL) || !ec_point_mul_scalar_precomp(group, &W1, &T_precomp, &key->x1, &S_precomp, &key->y1, NULL, NULL)) { return 0; } const int is_W0 = ec_affine_jacobian_equal(group, &W, &W0); const int is_W1 = ec_affine_jacobian_equal(group, &W, &W1); const int is_valid = is_W0 ^ is_W1; if (!is_valid) { // Invalid tokens will fail the validity check above. OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_INTERNAL_ERROR); return 0; } *out_private_metadata = is_W1; return 1; } // PMBTokens experiment v1. static int pmbtoken_exp1_hash_t(const EC_GROUP *group, EC_RAW_POINT *out, const uint8_t t[TRUST_TOKEN_NONCE_SIZE]) { const uint8_t kHashTLabel[] = "PMBTokens Experiment V1 HashT"; return ec_hash_to_curve_p384_xmd_sha512_sswu_draft07( group, out, kHashTLabel, sizeof(kHashTLabel), t, TRUST_TOKEN_NONCE_SIZE); } static int pmbtoken_exp1_hash_s(const EC_GROUP *group, EC_RAW_POINT *out, const EC_AFFINE *t, const uint8_t s[TRUST_TOKEN_NONCE_SIZE]) { const uint8_t kHashSLabel[] = "PMBTokens Experiment V1 HashS"; int ret = 0; CBB cbb; uint8_t *buf = NULL; size_t len; if (!CBB_init(&cbb, 0) || !point_to_cbb(&cbb, group, t) || !CBB_add_bytes(&cbb, s, TRUST_TOKEN_NONCE_SIZE) || !CBB_finish(&cbb, &buf, &len) || !ec_hash_to_curve_p384_xmd_sha512_sswu_draft07( group, out, kHashSLabel, sizeof(kHashSLabel), buf, len)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_MALLOC_FAILURE); goto err; } ret = 1; err: OPENSSL_free(buf); CBB_cleanup(&cbb); return ret; } static int pmbtoken_exp1_hash_c(const EC_GROUP *group, EC_SCALAR *out, uint8_t *buf, size_t len) { const uint8_t kHashCLabel[] = "PMBTokens Experiment V1 HashC"; return ec_hash_to_scalar_p384_xmd_sha512_draft07( group, out, kHashCLabel, sizeof(kHashCLabel), buf, len); } static int pmbtoken_exp1_ok = 0; static PMBTOKEN_METHOD pmbtoken_exp1_method; static CRYPTO_once_t pmbtoken_exp1_method_once = CRYPTO_ONCE_INIT; static void pmbtoken_exp1_init_method_impl(void) { // This is the output of |ec_hash_to_scalar_p384_xmd_sha512_draft07| with DST // "PMBTokens Experiment V1 HashH" and message "generator". static const uint8_t kH[] = { 0x04, 0x82, 0xd5, 0x68, 0xf5, 0x39, 0xf6, 0x08, 0x19, 0xa1, 0x75, 0x9f, 0x98, 0xb5, 0x10, 0xf5, 0x0b, 0x9d, 0x2b, 0xe1, 0x64, 0x4d, 0x02, 0x76, 0x18, 0x11, 0xf8, 0x2f, 0xd3, 0x33, 0x25, 0x1f, 0x2c, 0xb8, 0xf6, 0xf1, 0x9e, 0x93, 0x85, 0x79, 0xb3, 0xb7, 0x81, 0xa3, 0xe6, 0x23, 0xc3, 0x1c, 0xff, 0x03, 0xd9, 0x40, 0x6c, 0xec, 0xe0, 0x4d, 0xea, 0xdf, 0x9d, 0x94, 0xd1, 0x87, 0xab, 0x27, 0xf7, 0x4f, 0x53, 0xea, 0xa3, 0x18, 0x72, 0xb9, 0xd1, 0x56, 0xa0, 0x4e, 0x81, 0xaa, 0xeb, 0x1c, 0x22, 0x6d, 0x39, 0x1c, 0x5e, 0xb1, 0x27, 0xfc, 0x87, 0xc3, 0x95, 0xd0, 0x13, 0xb7, 0x0b, 0x5c, 0xc7, }; pmbtoken_exp1_ok = pmbtoken_init_method(&pmbtoken_exp1_method, NID_secp384r1, kH, sizeof(kH), pmbtoken_exp1_hash_t, pmbtoken_exp1_hash_s, pmbtoken_exp1_hash_c, 1); } static int pmbtoken_exp1_init_method(void) { CRYPTO_once(&pmbtoken_exp1_method_once, pmbtoken_exp1_init_method_impl); if (!pmbtoken_exp1_ok) { OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_INTERNAL_ERROR); return 0; } return 1; } int pmbtoken_exp1_generate_key(CBB *out_private, CBB *out_public) { if (!pmbtoken_exp1_init_method()) { return 0; } return pmbtoken_generate_key(&pmbtoken_exp1_method, out_private, out_public); } int pmbtoken_exp1_client_key_from_bytes(TRUST_TOKEN_CLIENT_KEY *key, const uint8_t *in, size_t len) { if (!pmbtoken_exp1_init_method()) { return 0; } return pmbtoken_client_key_from_bytes(&pmbtoken_exp1_method, key, in, len); } int pmbtoken_exp1_issuer_key_from_bytes(TRUST_TOKEN_ISSUER_KEY *key, const uint8_t *in, size_t len) { if (!pmbtoken_exp1_init_method()) { return 0; } return pmbtoken_issuer_key_from_bytes(&pmbtoken_exp1_method, key, in, len); } STACK_OF(TRUST_TOKEN_PRETOKEN) * pmbtoken_exp1_blind(CBB *cbb, size_t count) { if (!pmbtoken_exp1_init_method()) { return NULL; } return pmbtoken_blind(&pmbtoken_exp1_method, cbb, count); } int pmbtoken_exp1_sign(const TRUST_TOKEN_ISSUER_KEY *key, CBB *cbb, CBS *cbs, size_t num_requested, size_t num_to_issue, uint8_t private_metadata) { if (!pmbtoken_exp1_init_method()) { return 0; } return pmbtoken_sign(&pmbtoken_exp1_method, key, cbb, cbs, num_requested, num_to_issue, private_metadata); } STACK_OF(TRUST_TOKEN) * pmbtoken_exp1_unblind(const TRUST_TOKEN_CLIENT_KEY *key, const STACK_OF(TRUST_TOKEN_PRETOKEN) * pretokens, CBS *cbs, size_t count, uint32_t key_id) { if (!pmbtoken_exp1_init_method()) { return NULL; } return pmbtoken_unblind(&pmbtoken_exp1_method, key, pretokens, cbs, count, key_id); } int pmbtoken_exp1_read(const TRUST_TOKEN_ISSUER_KEY *key, uint8_t out_nonce[TRUST_TOKEN_NONCE_SIZE], uint8_t *out_private_metadata, const uint8_t *token, size_t token_len) { if (!pmbtoken_exp1_init_method()) { return 0; } return pmbtoken_read(&pmbtoken_exp1_method, key, out_nonce, out_private_metadata, token, token_len); } int pmbtoken_exp1_get_h_for_testing(uint8_t out[97]) { if (!pmbtoken_exp1_init_method()) { return 0; } EC_AFFINE h; return ec_jacobian_to_affine(pmbtoken_exp1_method.group, &h, &pmbtoken_exp1_method.h) && ec_point_to_bytes(pmbtoken_exp1_method.group, &h, POINT_CONVERSION_UNCOMPRESSED, out, 97) == 97; } // PMBTokens experiment v2. static int pmbtoken_exp2_hash_t(const EC_GROUP *group, EC_RAW_POINT *out, const uint8_t t[TRUST_TOKEN_NONCE_SIZE]) { const uint8_t kHashTLabel[] = "PMBTokens Experiment V2 HashT"; return ec_hash_to_curve_p384_xmd_sha512_sswu_draft07( group, out, kHashTLabel, sizeof(kHashTLabel), t, TRUST_TOKEN_NONCE_SIZE); } static int pmbtoken_exp2_hash_s(const EC_GROUP *group, EC_RAW_POINT *out, const EC_AFFINE *t, const uint8_t s[TRUST_TOKEN_NONCE_SIZE]) { const uint8_t kHashSLabel[] = "PMBTokens Experiment V2 HashS"; int ret = 0; CBB cbb; uint8_t *buf = NULL; size_t len; if (!CBB_init(&cbb, 0) || !point_to_cbb(&cbb, group, t) || !CBB_add_bytes(&cbb, s, TRUST_TOKEN_NONCE_SIZE) || !CBB_finish(&cbb, &buf, &len) || !ec_hash_to_curve_p384_xmd_sha512_sswu_draft07( group, out, kHashSLabel, sizeof(kHashSLabel), buf, len)) { OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_MALLOC_FAILURE); goto err; } ret = 1; err: OPENSSL_free(buf); CBB_cleanup(&cbb); return ret; } static int pmbtoken_exp2_hash_c(const EC_GROUP *group, EC_SCALAR *out, uint8_t *buf, size_t len) { const uint8_t kHashCLabel[] = "PMBTokens Experiment V2 HashC"; return ec_hash_to_scalar_p384_xmd_sha512_draft07( group, out, kHashCLabel, sizeof(kHashCLabel), buf, len); } static int pmbtoken_exp2_ok = 0; static PMBTOKEN_METHOD pmbtoken_exp2_method; static CRYPTO_once_t pmbtoken_exp2_method_once = CRYPTO_ONCE_INIT; static void pmbtoken_exp2_init_method_impl(void) { // This is the output of |ec_hash_to_scalar_p384_xmd_sha512_draft07| with DST // "PMBTokens Experiment V2 HashH" and message "generator". static const uint8_t kH[] = { 0x04, 0xbc, 0x27, 0x24, 0x99, 0xfa, 0xc9, 0xa4, 0x74, 0x6f, 0xf9, 0x07, 0x81, 0x55, 0xf8, 0x1f, 0x6f, 0xda, 0x09, 0xe7, 0x8c, 0x5d, 0x9e, 0x4e, 0x14, 0x7c, 0x53, 0x14, 0xbc, 0x7e, 0x29, 0x57, 0x92, 0x17, 0x94, 0x6e, 0xd2, 0xdf, 0xa5, 0x31, 0x1b, 0x4e, 0xb7, 0xfc, 0x93, 0xe3, 0x6e, 0x14, 0x1f, 0x4f, 0x14, 0xf3, 0xe5, 0x47, 0x61, 0x1c, 0x2c, 0x72, 0x25, 0xf0, 0x4a, 0x45, 0x23, 0x2d, 0x57, 0x93, 0x0e, 0xb2, 0x55, 0xb8, 0x57, 0x25, 0x4c, 0x1e, 0xdb, 0xfd, 0x58, 0x70, 0x17, 0x9a, 0xbb, 0x9e, 0x5e, 0x93, 0x9e, 0x92, 0xd3, 0xe8, 0x25, 0x62, 0xbf, 0x59, 0xb2, 0xd2, 0x3d, 0x71, 0xff }; pmbtoken_exp2_ok = pmbtoken_init_method(&pmbtoken_exp2_method, NID_secp384r1, kH, sizeof(kH), pmbtoken_exp2_hash_t, pmbtoken_exp2_hash_s, pmbtoken_exp2_hash_c, 0); } static int pmbtoken_exp2_init_method(void) { CRYPTO_once(&pmbtoken_exp2_method_once, pmbtoken_exp2_init_method_impl); if (!pmbtoken_exp2_ok) { OPENSSL_PUT_ERROR(TRUST_TOKEN, ERR_R_INTERNAL_ERROR); return 0; } return 1; } int pmbtoken_exp2_generate_key(CBB *out_private, CBB *out_public) { if (!pmbtoken_exp2_init_method()) { return 0; } return pmbtoken_generate_key(&pmbtoken_exp2_method, out_private, out_public); } int pmbtoken_exp2_client_key_from_bytes(TRUST_TOKEN_CLIENT_KEY *key, const uint8_t *in, size_t len) { if (!pmbtoken_exp2_init_method()) { return 0; } return pmbtoken_client_key_from_bytes(&pmbtoken_exp2_method, key, in, len); } int pmbtoken_exp2_issuer_key_from_bytes(TRUST_TOKEN_ISSUER_KEY *key, const uint8_t *in, size_t len) { if (!pmbtoken_exp2_init_method()) { return 0; } return pmbtoken_issuer_key_from_bytes(&pmbtoken_exp2_method, key, in, len); } STACK_OF(TRUST_TOKEN_PRETOKEN) * pmbtoken_exp2_blind(CBB *cbb, size_t count) { if (!pmbtoken_exp2_init_method()) { return NULL; } return pmbtoken_blind(&pmbtoken_exp2_method, cbb, count); } int pmbtoken_exp2_sign(const TRUST_TOKEN_ISSUER_KEY *key, CBB *cbb, CBS *cbs, size_t num_requested, size_t num_to_issue, uint8_t private_metadata) { if (!pmbtoken_exp2_init_method()) { return 0; } return pmbtoken_sign(&pmbtoken_exp2_method, key, cbb, cbs, num_requested, num_to_issue, private_metadata); } STACK_OF(TRUST_TOKEN) * pmbtoken_exp2_unblind(const TRUST_TOKEN_CLIENT_KEY *key, const STACK_OF(TRUST_TOKEN_PRETOKEN) * pretokens, CBS *cbs, size_t count, uint32_t key_id) { if (!pmbtoken_exp2_init_method()) { return NULL; } return pmbtoken_unblind(&pmbtoken_exp2_method, key, pretokens, cbs, count, key_id); } int pmbtoken_exp2_read(const TRUST_TOKEN_ISSUER_KEY *key, uint8_t out_nonce[TRUST_TOKEN_NONCE_SIZE], uint8_t *out_private_metadata, const uint8_t *token, size_t token_len) { if (!pmbtoken_exp2_init_method()) { return 0; } return pmbtoken_read(&pmbtoken_exp2_method, key, out_nonce, out_private_metadata, token, token_len); } int pmbtoken_exp2_get_h_for_testing(uint8_t out[97]) { if (!pmbtoken_exp2_init_method()) { return 0; } EC_AFFINE h; return ec_jacobian_to_affine(pmbtoken_exp2_method.group, &h, &pmbtoken_exp2_method.h) && ec_point_to_bytes(pmbtoken_exp2_method.group, &h, POINT_CONVERSION_UNCOMPRESSED, out, 97) == 97; }