diff options
Diffstat (limited to 'src/crypto/crypto.cpp')
| -rw-r--r-- | src/crypto/crypto.cpp | 135 |
1 files changed, 129 insertions, 6 deletions
diff --git a/src/crypto/crypto.cpp b/src/crypto/crypto.cpp index 8a03f28bb..4cfe83d54 100644 --- a/src/crypto/crypto.cpp +++ b/src/crypto/crypto.cpp @@ -1,4 +1,4 @@ -// Copyright (c) 2014-2019, The Monero Project +// Copyright (c) 2014-2020, The Monero Project // // All rights reserved. // @@ -43,6 +43,8 @@ #include "crypto.h" #include "hash.h" +#include "cryptonote_config.h" + namespace { static void local_abort(const char *msg) { @@ -261,11 +263,24 @@ namespace crypto { ec_point comm; }; + // Used in v1 tx proofs + struct s_comm_2_v1 { + hash msg; + ec_point D; + ec_point X; + ec_point Y; + }; + + // Used in v1/v2 tx proofs struct s_comm_2 { hash msg; ec_point D; ec_point X; ec_point Y; + hash sep; // domain separation + ec_point R; + ec_point A; + ec_point B; }; void crypto_ops::generate_signature(const hash &prefix_hash, const public_key &pub, const secret_key &sec, signature &sig) { @@ -321,6 +336,86 @@ namespace crypto { return sc_isnonzero(&c) == 0; } + // Generate a proof of knowledge of `r` such that (`R = rG` and `D = rA`) or (`R = rB` and `D = rA`) via a Schnorr proof + // This handles use cases for both standard addresses and subaddresses + // + // NOTE: This generates old v1 proofs, and is for TESTING ONLY + void crypto_ops::generate_tx_proof_v1(const hash &prefix_hash, const public_key &R, const public_key &A, const boost::optional<public_key> &B, const public_key &D, const secret_key &r, signature &sig) { + // sanity check + ge_p3 R_p3; + ge_p3 A_p3; + ge_p3 B_p3; + ge_p3 D_p3; + if (ge_frombytes_vartime(&R_p3, &R) != 0) throw std::runtime_error("tx pubkey is invalid"); + if (ge_frombytes_vartime(&A_p3, &A) != 0) throw std::runtime_error("recipient view pubkey is invalid"); + if (B && ge_frombytes_vartime(&B_p3, &*B) != 0) throw std::runtime_error("recipient spend pubkey is invalid"); + if (ge_frombytes_vartime(&D_p3, &D) != 0) throw std::runtime_error("key derivation is invalid"); +#if !defined(NDEBUG) + { + assert(sc_check(&r) == 0); + // check R == r*G or R == r*B + public_key dbg_R; + if (B) + { + ge_p2 dbg_R_p2; + ge_scalarmult(&dbg_R_p2, &r, &B_p3); + ge_tobytes(&dbg_R, &dbg_R_p2); + } + else + { + ge_p3 dbg_R_p3; + ge_scalarmult_base(&dbg_R_p3, &r); + ge_p3_tobytes(&dbg_R, &dbg_R_p3); + } + assert(R == dbg_R); + // check D == r*A + ge_p2 dbg_D_p2; + ge_scalarmult(&dbg_D_p2, &r, &A_p3); + public_key dbg_D; + ge_tobytes(&dbg_D, &dbg_D_p2); + assert(D == dbg_D); + } +#endif + + // pick random k + ec_scalar k; + random_scalar(k); + + s_comm_2_v1 buf; + buf.msg = prefix_hash; + buf.D = D; + + if (B) + { + // compute X = k*B + ge_p2 X_p2; + ge_scalarmult(&X_p2, &k, &B_p3); + ge_tobytes(&buf.X, &X_p2); + } + else + { + // compute X = k*G + ge_p3 X_p3; + ge_scalarmult_base(&X_p3, &k); + ge_p3_tobytes(&buf.X, &X_p3); + } + + // compute Y = k*A + ge_p2 Y_p2; + ge_scalarmult(&Y_p2, &k, &A_p3); + ge_tobytes(&buf.Y, &Y_p2); + + // sig.c = Hs(Msg || D || X || Y) + hash_to_scalar(&buf, sizeof(buf), sig.c); + + // sig.r = k - sig.c*r + sc_mulsub(&sig.r, &sig.c, &unwrap(r), &k); + } + + // Generate a proof of knowledge of `r` such that (`R = rG` and `D = rA`) or (`R = rB` and `D = rA`) via a Schnorr proof + // This handles use cases for both standard addresses and subaddresses + // + // Generates only proofs for InProofV2 and OutProofV2 void crypto_ops::generate_tx_proof(const hash &prefix_hash, const public_key &R, const public_key &A, const boost::optional<public_key> &B, const public_key &D, const secret_key &r, signature &sig) { // sanity check ge_p3 R_p3; @@ -362,10 +457,20 @@ namespace crypto { ec_scalar k; random_scalar(k); + // if B is not present + static const ec_point zero = {{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }}; + s_comm_2 buf; buf.msg = prefix_hash; buf.D = D; - + buf.R = R; + buf.A = A; + if (B) + buf.B = *B; + else + buf.B = zero; + cn_fast_hash(config::HASH_KEY_TXPROOF_V2, sizeof(config::HASH_KEY_TXPROOF_V2)-1, buf.sep); + if (B) { // compute X = k*B @@ -386,7 +491,7 @@ namespace crypto { ge_scalarmult(&Y_p2, &k, &A_p3); ge_tobytes(&buf.Y, &Y_p2); - // sig.c = Hs(Msg || D || X || Y) + // sig.c = Hs(Msg || D || X || Y || sep || R || A || B) hash_to_scalar(&buf, sizeof(buf), sig.c); // sig.r = k - sig.c*r @@ -395,7 +500,8 @@ namespace crypto { memwipe(&k, sizeof(k)); } - bool crypto_ops::check_tx_proof(const hash &prefix_hash, const public_key &R, const public_key &A, const boost::optional<public_key> &B, const public_key &D, const signature &sig) { + // Verify a proof: either v1 (version == 1) or v2 (version == 2) + bool crypto_ops::check_tx_proof(const hash &prefix_hash, const public_key &R, const public_key &A, const boost::optional<public_key> &B, const public_key &D, const signature &sig, const int version) { // sanity check ge_p3 R_p3; ge_p3 A_p3; @@ -467,14 +573,31 @@ namespace crypto { ge_p2 Y_p2; ge_p1p1_to_p2(&Y_p2, &Y_p1p1); - // compute c2 = Hs(Msg || D || X || Y) + // Compute hash challenge + // for v1, c2 = Hs(Msg || D || X || Y) + // for v2, c2 = Hs(Msg || D || X || Y || sep || R || A || B) + + // if B is not present + static const ec_point zero = {{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }}; + s_comm_2 buf; buf.msg = prefix_hash; buf.D = D; + buf.R = R; + buf.A = A; + if (B) + buf.B = *B; + else + buf.B = zero; + cn_fast_hash(config::HASH_KEY_TXPROOF_V2, sizeof(config::HASH_KEY_TXPROOF_V2)-1, buf.sep); ge_tobytes(&buf.X, &X_p2); ge_tobytes(&buf.Y, &Y_p2); ec_scalar c2; - hash_to_scalar(&buf, sizeof(s_comm_2), c2); + + // Hash depends on version + if (version == 1) hash_to_scalar(&buf, sizeof(s_comm_2) - 3*sizeof(ec_point) - sizeof(hash), c2); + else if (version == 2) hash_to_scalar(&buf, sizeof(s_comm_2), c2); + else return false; // test if c2 == sig.c sc_sub(&c2, &c2, &sig.c); |