Updates InProofV1, OutProofV1, and ReserveProofV1 to new V2 variants that include all public proof parameters in Schnorr challenges, along with hash function domain separators. Includes new randomized unit tests.

4 files changed, 167 insertions, 26 deletions

diff --git a/src/crypto/crypto.cpp b/src/crypto/crypto.cpp
index 1e4a6d33f..4cfe83d54 100644
--- a/src/crypto/crypto.cpp
+++ b/src/crypto/crypto.cpp
@@ -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);
diff --git a/src/crypto/crypto.h b/src/crypto/crypto.h
index 70d463a16..7ddc0150f 100644
--- a/src/crypto/crypto.h
+++ b/src/crypto/crypto.h
@@ -132,8 +132,10 @@ namespace crypto {
     friend bool check_signature(const hash &, const public_key &, const signature &);
     static void generate_tx_proof(const hash &, const public_key &, const public_key &, const boost::optional<public_key> &, const public_key &, const secret_key &, signature &);
     friend void generate_tx_proof(const hash &, const public_key &, const public_key &, const boost::optional<public_key> &, const public_key &, const secret_key &, signature &);
-    static bool check_tx_proof(const hash &, const public_key &, const public_key &, const boost::optional<public_key> &, const public_key &, const signature &);
-    friend bool check_tx_proof(const hash &, const public_key &, const public_key &, const boost::optional<public_key> &, const public_key &, const signature &);
+    static void generate_tx_proof_v1(const hash &, const public_key &, const public_key &, const boost::optional<public_key> &, const public_key &, const secret_key &, signature &);
+    friend void generate_tx_proof_v1(const hash &, const public_key &, const public_key &, const boost::optional<public_key> &, const public_key &, const secret_key &, signature &);
+    static bool check_tx_proof(const hash &, const public_key &, const public_key &, const boost::optional<public_key> &, const public_key &, const signature &, const int);
+    friend bool check_tx_proof(const hash &, const public_key &, const public_key &, const boost::optional<public_key> &, const public_key &, const signature &, const int);
     static void generate_key_image(const public_key &, const secret_key &, key_image &);
     friend void generate_key_image(const public_key &, const secret_key &, key_image &);
     static void generate_ring_signature(const hash &, const key_image &,
@@ -248,8 +250,11 @@ namespace crypto {
   inline void 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) {
     crypto_ops::generate_tx_proof(prefix_hash, R, A, B, D, r, sig);
   }
-  inline bool 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) {
-    return crypto_ops::check_tx_proof(prefix_hash, R, A, B, D, sig);
+  inline void 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) {
+    crypto_ops::generate_tx_proof_v1(prefix_hash, R, A, B, D, r, sig);
+  }
+  inline bool 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) {
+    return crypto_ops::check_tx_proof(prefix_hash, R, A, B, D, sig, version);
   }
 
   /* To send money to a key:
diff --git a/src/cryptonote_config.h b/src/cryptonote_config.h
index 87bb4e15a..7dc883c90 100644
--- a/src/cryptonote_config.h
+++ b/src/cryptonote_config.h
@@ -219,6 +219,7 @@ namespace config
   const unsigned char HASH_KEY_RPC_PAYMENT_NONCE = 0x58;
   const unsigned char HASH_KEY_MEMORY = 'k';
   const unsigned char HASH_KEY_MULTISIG[] = {'M', 'u', 'l', 't' , 'i', 's', 'i', 'g', 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
+  const unsigned char HASH_KEY_TXPROOF_V2[] = "TXPROOF_V2";
 
   namespace testnet
   {
diff --git a/src/wallet/wallet2.cpp b/src/wallet/wallet2.cpp
index d7ed3e999..760693b60 100644
--- a/src/wallet/wallet2.cpp
+++ b/src/wallet/wallet2.cpp
@@ -11425,7 +11425,7 @@ std::string wallet2::get_tx_proof(const cryptonote::transaction &tx, const crypt
         hwdev.generate_tx_proof(prefix_hash, tx_pub_key, address.m_view_public_key, boost::none, shared_secret[i], additional_tx_keys[i - 1], sig[i]);
       }
     }
-    sig_str = std::string("OutProofV1");
+    sig_str = std::string("OutProofV2");
   }
   else
   {
@@ -11461,7 +11461,7 @@ std::string wallet2::get_tx_proof(const cryptonote::transaction &tx, const crypt
         hwdev.generate_tx_proof(prefix_hash, address.m_view_public_key, additional_tx_pub_keys[i - 1], boost::none, shared_secret[i], a, sig[i]);
       }
     }
-    sig_str = std::string("InProofV1");
+    sig_str = std::string("InProofV2");
   }
   const size_t num_sigs = shared_secret.size();
 
@@ -11540,8 +11540,14 @@ bool wallet2::check_tx_proof(const crypto::hash &txid, const cryptonote::account
 
 bool wallet2::check_tx_proof(const cryptonote::transaction &tx, const cryptonote::account_public_address &address, bool is_subaddress, const std::string &message, const std::string &sig_str, uint64_t &received) const
 {
+  // InProofV1, InProofV2, OutProofV1, OutProofV2
   const bool is_out = sig_str.substr(0, 3) == "Out";
-  const std::string header = is_out ? "OutProofV1" : "InProofV1";
+  const std::string header = is_out ? sig_str.substr(0,10) : sig_str.substr(0,9);
+  int version = 2; // InProofV2
+  if (is_out && sig_str.substr(8,2) == "V1") version = 1; // OutProofV1
+  else if (is_out) version = 2; // OutProofV2
+  else if (sig_str.substr(7,2) == "V1") version = 1; // InProofV1
+
   const size_t header_len = header.size();
   THROW_WALLET_EXCEPTION_IF(sig_str.size() < header_len || sig_str.substr(0, header_len) != header, error::wallet_internal_error,
     "Signature header check error");
@@ -11588,27 +11594,27 @@ bool wallet2::check_tx_proof(const cryptonote::transaction &tx, const cryptonote
   if (is_out)
   {
     good_signature[0] = is_subaddress ?
-      crypto::check_tx_proof(prefix_hash, tx_pub_key, address.m_view_public_key, address.m_spend_public_key, shared_secret[0], sig[0]) :
-      crypto::check_tx_proof(prefix_hash, tx_pub_key, address.m_view_public_key, boost::none, shared_secret[0], sig[0]);
+      crypto::check_tx_proof(prefix_hash, tx_pub_key, address.m_view_public_key, address.m_spend_public_key, shared_secret[0], sig[0], version) :
+      crypto::check_tx_proof(prefix_hash, tx_pub_key, address.m_view_public_key, boost::none, shared_secret[0], sig[0], version);
 
     for (size_t i = 0; i < additional_tx_pub_keys.size(); ++i)
     {
       good_signature[i + 1] = is_subaddress ?
-        crypto::check_tx_proof(prefix_hash, additional_tx_pub_keys[i], address.m_view_public_key, address.m_spend_public_key, shared_secret[i + 1], sig[i + 1]) :
-        crypto::check_tx_proof(prefix_hash, additional_tx_pub_keys[i], address.m_view_public_key, boost::none, shared_secret[i + 1], sig[i + 1]);
+        crypto::check_tx_proof(prefix_hash, additional_tx_pub_keys[i], address.m_view_public_key, address.m_spend_public_key, shared_secret[i + 1], sig[i + 1], version) :
+        crypto::check_tx_proof(prefix_hash, additional_tx_pub_keys[i], address.m_view_public_key, boost::none, shared_secret[i + 1], sig[i + 1], version);
     }
   }
   else
   {
     good_signature[0] = is_subaddress ?
-      crypto::check_tx_proof(prefix_hash, address.m_view_public_key, tx_pub_key, address.m_spend_public_key, shared_secret[0], sig[0]) :
-      crypto::check_tx_proof(prefix_hash, address.m_view_public_key, tx_pub_key, boost::none, shared_secret[0], sig[0]);
+      crypto::check_tx_proof(prefix_hash, address.m_view_public_key, tx_pub_key, address.m_spend_public_key, shared_secret[0], sig[0], version) :
+      crypto::check_tx_proof(prefix_hash, address.m_view_public_key, tx_pub_key, boost::none, shared_secret[0], sig[0], version);
 
     for (size_t i = 0; i < additional_tx_pub_keys.size(); ++i)
     {
       good_signature[i + 1] = is_subaddress ?
-        crypto::check_tx_proof(prefix_hash, address.m_view_public_key, additional_tx_pub_keys[i], address.m_spend_public_key, shared_secret[i + 1], sig[i + 1]) :
-        crypto::check_tx_proof(prefix_hash, address.m_view_public_key, additional_tx_pub_keys[i], boost::none, shared_secret[i + 1], sig[i + 1]);
+        crypto::check_tx_proof(prefix_hash, address.m_view_public_key, additional_tx_pub_keys[i], address.m_spend_public_key, shared_secret[i + 1], sig[i + 1], version) :
+        crypto::check_tx_proof(prefix_hash, address.m_view_public_key, additional_tx_pub_keys[i], boost::none, shared_secret[i + 1], sig[i + 1], version);
     }
   }
 
@@ -11746,7 +11752,7 @@ std::string wallet2::get_reserve_proof(const boost::optional<std::pair<uint32_t,
   std::ostringstream oss;
   boost::archive::portable_binary_oarchive ar(oss);
   ar << proofs << subaddr_spendkeys;
-  return "ReserveProofV1" + tools::base58::encode(oss.str());
+  return "ReserveProofV2" + tools::base58::encode(oss.str());
 }
 
 bool wallet2::check_reserve_proof(const cryptonote::account_public_address &address, const std::string &message, const std::string &sig_str, uint64_t &total, uint64_t &spent)
@@ -11755,12 +11761,18 @@ bool wallet2::check_reserve_proof(const cryptonote::account_public_address &addr
   THROW_WALLET_EXCEPTION_IF(!check_connection(&rpc_version), error::wallet_internal_error, "Failed to connect to daemon: " + get_daemon_address());
   THROW_WALLET_EXCEPTION_IF(rpc_version < MAKE_CORE_RPC_VERSION(1, 0), error::wallet_internal_error, "Daemon RPC version is too old");
 
-  static constexpr char header[] = "ReserveProofV1";
-  THROW_WALLET_EXCEPTION_IF(!boost::string_ref{sig_str}.starts_with(header), error::wallet_internal_error,
+  static constexpr char header_v1[] = "ReserveProofV1";
+  static constexpr char header_v2[] = "ReserveProofV2"; // assumes same length as header_v1
+  THROW_WALLET_EXCEPTION_IF(!boost::string_ref{sig_str}.starts_with(header_v1) && !boost::string_ref{sig_str}.starts_with(header_v2), error::wallet_internal_error,
     "Signature header check error");
+  int version = 2; // assume newest version
+  if (boost::string_ref{sig_str}.starts_with(header_v1))
+      version = 1;
+  else if (boost::string_ref{sig_str}.starts_with(header_v2))
+      version = 2;
 
   std::string sig_decoded;
-  THROW_WALLET_EXCEPTION_IF(!tools::base58::decode(sig_str.substr(std::strlen(header)), sig_decoded), error::wallet_internal_error,
+  THROW_WALLET_EXCEPTION_IF(!tools::base58::decode(sig_str.substr(std::strlen(header_v1)), sig_decoded), error::wallet_internal_error,
     "Signature decoding error");
 
   std::istringstream iss(sig_decoded);
@@ -11841,9 +11853,9 @@ bool wallet2::check_reserve_proof(const cryptonote::account_public_address &addr
     const std::vector<crypto::public_key> additional_tx_pub_keys = get_additional_tx_pub_keys_from_extra(tx);
 
     // check singature for shared secret
-    ok = crypto::check_tx_proof(prefix_hash, address.m_view_public_key, tx_pub_key, boost::none, proof.shared_secret, proof.shared_secret_sig);
+    ok = crypto::check_tx_proof(prefix_hash, address.m_view_public_key, tx_pub_key, boost::none, proof.shared_secret, proof.shared_secret_sig, version);
     if (!ok && additional_tx_pub_keys.size() == tx.vout.size())
-      ok = crypto::check_tx_proof(prefix_hash, address.m_view_public_key, additional_tx_pub_keys[proof.index_in_tx], boost::none, proof.shared_secret, proof.shared_secret_sig);
+      ok = crypto::check_tx_proof(prefix_hash, address.m_view_public_key, additional_tx_pub_keys[proof.index_in_tx], boost::none, proof.shared_secret, proof.shared_secret_sig, version);
     if (!ok)
       return false;