encrypted payment ids are now 64 bit, instead of 256 bit

Pros:
 - smaller on the blockchain
 - shorter integrated addresses

Cons:
 - less sparseness
 - less ability to embed actual information

The boolean argument to encrypt payment ids is now gone from the
RPC calls, since the decision is made based on the length of the
payment id passed.

7 files changed, 51 insertions, 27 deletions

diff --git a/src/cryptonote_core/account.cpp b/src/cryptonote_core/account.cpp
index eb79f5949..fe8dbd1e8 100644
--- a/src/cryptonote_core/account.cpp
+++ b/src/cryptonote_core/account.cpp
@@ -120,7 +120,7 @@ DISABLE_VS_WARNINGS(4244 4345)
     return get_account_address_as_str(testnet, m_keys.m_account_address);
   }
   //-----------------------------------------------------------------
-  std::string account_base::get_public_integrated_address_str(const crypto::hash &payment_id, bool testnet) const
+  std::string account_base::get_public_integrated_address_str(const crypto::hash8 &payment_id, bool testnet) const
   {
     //TODO: change this code into base 58
     return get_account_integrated_address_as_str(testnet, m_keys.m_account_address, payment_id);
diff --git a/src/cryptonote_core/account.h b/src/cryptonote_core/account.h
index 088363bf1..732645ee4 100644
--- a/src/cryptonote_core/account.h
+++ b/src/cryptonote_core/account.h
@@ -61,7 +61,7 @@ namespace cryptonote
     void create_from_viewkey(const cryptonote::account_public_address& address, const crypto::secret_key& viewkey);
     const account_keys& get_keys() const;
     std::string get_public_address_str(bool testnet) const;
-    std::string get_public_integrated_address_str(const crypto::hash &payment_id, bool testnet) const;
+    std::string get_public_integrated_address_str(const crypto::hash8 &payment_id, bool testnet) const;
 
     uint64_t get_createtime() const { return m_creation_timestamp; }
     void set_createtime(uint64_t val) { m_creation_timestamp = val; }
diff --git a/src/cryptonote_core/cryptonote_basic.h b/src/cryptonote_core/cryptonote_basic.h
index 2be76c0de..07745bf0d 100644
--- a/src/cryptonote_core/cryptonote_basic.h
+++ b/src/cryptonote_core/cryptonote_basic.h
@@ -57,6 +57,7 @@ namespace cryptonote
 {
 
   const static crypto::hash null_hash = AUTO_VAL_INIT(null_hash);
+  const static crypto::hash8 null_hash8 = AUTO_VAL_INIT(null_hash8);
   const static crypto::public_key null_pkey = AUTO_VAL_INIT(null_pkey);
 
   typedef std::vector<crypto::signature> ring_signature;
diff --git a/src/cryptonote_core/cryptonote_basic_impl.cpp b/src/cryptonote_core/cryptonote_basic_impl.cpp
index 1319a2ef9..bd0b8a304 100644
--- a/src/cryptonote_core/cryptonote_basic_impl.cpp
+++ b/src/cryptonote_core/cryptonote_basic_impl.cpp
@@ -46,7 +46,7 @@ namespace cryptonote {
 
   struct integrated_address {
     account_public_address adr;
-    crypto::hash payment_id;
+    crypto::hash8 payment_id;
 
     BEGIN_SERIALIZE_OBJECT()
       FIELD(adr)
@@ -150,7 +150,7 @@ namespace cryptonote {
   std::string get_account_integrated_address_as_str(
       bool testnet
     , account_public_address const & adr
-    , crypto::hash const & payment_id
+    , crypto::hash8 const & payment_id
     )
   {
     uint64_t integrated_address_prefix = testnet ?
@@ -176,7 +176,7 @@ namespace cryptonote {
   bool get_account_integrated_address_from_str(
       account_public_address& adr
     , bool& has_payment_id
-    , crypto::hash& payment_id
+    , crypto::hash8& payment_id
     , bool testnet
     , std::string const & str
     )
@@ -278,7 +278,7 @@ namespace cryptonote {
     )
   {
     bool has_payment_id;
-    crypto::hash payment_id;
+    crypto::hash8 payment_id;
     return get_account_integrated_address_from_str(adr, has_payment_id, payment_id, testnet, str);
   }
 
diff --git a/src/cryptonote_core/cryptonote_basic_impl.h b/src/cryptonote_core/cryptonote_basic_impl.h
index 87d6f1024..5c442d558 100644
--- a/src/cryptonote_core/cryptonote_basic_impl.h
+++ b/src/cryptonote_core/cryptonote_basic_impl.h
@@ -60,7 +60,7 @@ namespace cryptonote {
   {
     uint8_t m_ver;
     account_public_address m_address;
-    crypto::hash payment_id;
+    crypto::hash8 payment_id;
     uint8_t check_sum;
   };
 #pragma pack (pop)
@@ -83,13 +83,13 @@ namespace cryptonote {
   std::string get_account_integrated_address_as_str(
       bool testnet
     , const account_public_address& adr
-    , const crypto::hash& payment_id
+    , const crypto::hash8& payment_id
     );
 
   bool get_account_integrated_address_from_str(
       account_public_address& adr
     , bool& has_payment_id
-    , crypto::hash& payment_id
+    , crypto::hash8& payment_id
     , bool testnet
     , const std::string& str
     );
@@ -110,6 +110,10 @@ template <class T>
 std::ostream &print256(std::ostream &o, const T &v) {
   return o << "<" << epee::string_tools::pod_to_hex(v) << ">";
 }
+template <class T>
+std::ostream &print64(std::ostream &o, const T &v) {
+  return o << "<" << epee::string_tools::pod_to_hex(v) << ">";
+}
 
 bool parse_hash256(const std::string str_hash, crypto::hash& hash);
 
@@ -120,4 +124,5 @@ namespace crypto {
   inline std::ostream &operator <<(std::ostream &o, const crypto::key_image &v) { return print256(o, v); }
   inline std::ostream &operator <<(std::ostream &o, const crypto::signature &v) { return print256(o, v); }
   inline std::ostream &operator <<(std::ostream &o, const crypto::hash &v) { return print256(o, v); }
+  inline std::ostream &operator <<(std::ostream &o, const crypto::hash8 &v) { return print64(o, v); }
 }
diff --git a/src/cryptonote_core/cryptonote_format_utils.cpp b/src/cryptonote_core/cryptonote_format_utils.cpp
index a79c3cdd3..af8e703bf 100644
--- a/src/cryptonote_core/cryptonote_format_utils.cpp
+++ b/src/cryptonote_core/cryptonote_format_utils.cpp
@@ -334,26 +334,43 @@ namespace cryptonote
     return true;
   }
   //---------------------------------------------------------------
-  void set_payment_id_to_tx_extra_nonce(blobdata& extra_nonce, const crypto::hash& payment_id, bool encrypted)
+  void set_payment_id_to_tx_extra_nonce(blobdata& extra_nonce, const crypto::hash& payment_id)
   {
     extra_nonce.clear();
-    extra_nonce.push_back(encrypted ? TX_EXTRA_NONCE_ENCRYPTED_PAYMENT_ID : TX_EXTRA_NONCE_PAYMENT_ID);
+    extra_nonce.push_back(TX_EXTRA_NONCE_PAYMENT_ID);
     const uint8_t* payment_id_ptr = reinterpret_cast<const uint8_t*>(&payment_id);
     std::copy(payment_id_ptr, payment_id_ptr + sizeof(payment_id), std::back_inserter(extra_nonce));
   }
   //---------------------------------------------------------------
-  bool get_payment_id_from_tx_extra_nonce(const blobdata& extra_nonce, crypto::hash& payment_id, bool &encrypted)
+  void set_encrypted_payment_id_to_tx_extra_nonce(blobdata& extra_nonce, const crypto::hash8& payment_id)
+  {
+    extra_nonce.clear();
+    extra_nonce.push_back(TX_EXTRA_NONCE_ENCRYPTED_PAYMENT_ID);
+    const uint8_t* payment_id_ptr = reinterpret_cast<const uint8_t*>(&payment_id);
+    std::copy(payment_id_ptr, payment_id_ptr + sizeof(payment_id), std::back_inserter(extra_nonce));
+  }
+  //---------------------------------------------------------------
+  bool get_payment_id_from_tx_extra_nonce(const blobdata& extra_nonce, crypto::hash& payment_id)
   {
     if(sizeof(crypto::hash) + 1 != extra_nonce.size())
       return false;
-    if(TX_EXTRA_NONCE_PAYMENT_ID != extra_nonce[0] && TX_EXTRA_NONCE_ENCRYPTED_PAYMENT_ID != extra_nonce[0])
+    if(TX_EXTRA_NONCE_PAYMENT_ID != extra_nonce[0])
       return false;
     payment_id = *reinterpret_cast<const crypto::hash*>(extra_nonce.data() + 1);
-    encrypted = TX_EXTRA_NONCE_ENCRYPTED_PAYMENT_ID == extra_nonce[0];
     return true;
   }
   //---------------------------------------------------------------
-  crypto::public_key get_destination_view_key_pub(const std::vector<tx_destination_entry> &destinations)
+  bool get_encrypted_payment_id_from_tx_extra_nonce(const blobdata& extra_nonce, crypto::hash8& payment_id)
+  {
+    if(sizeof(crypto::hash8) + 1 != extra_nonce.size())
+      return false;
+    if (TX_EXTRA_NONCE_ENCRYPTED_PAYMENT_ID != extra_nonce[0])
+      return false;
+    payment_id = *reinterpret_cast<const crypto::hash8*>(extra_nonce.data() + 1);
+    return true;
+  }
+  //---------------------------------------------------------------
+  crypto::public_key get_destination_view_key_pub(const std::vector<tx_destination_entry> &destinations, const account_keys &sender_keys)
   {
     if (destinations.empty())
       return null_pkey;
@@ -367,7 +384,7 @@ namespace cryptonote
     return destinations[0].addr.m_view_public_key;
   }
   //---------------------------------------------------------------
-  bool encrypt_payment_id(crypto::hash &payment_id, const crypto::public_key &public_key, const crypto::secret_key &secret_key)
+  bool encrypt_payment_id(crypto::hash8 &payment_id, const crypto::public_key &public_key, const crypto::secret_key &secret_key)
   {
     crypto::key_derivation derivation;
     crypto::hash hash;
@@ -380,12 +397,12 @@ namespace cryptonote
     data[32] = ENCRYPTED_PAYMENT_ID_TAIL;
     cn_fast_hash(data, 33, hash);
 
-    for (size_t b = 0; b < 32; ++b)
+    for (size_t b = 0; b < 8; ++b)
       payment_id.data[b] ^= hash.data[b];
 
     return true;
   }
-  bool decrypt_payment_id(crypto::hash &payment_id, const crypto::public_key &public_key, const crypto::secret_key &secret_key)
+  bool decrypt_payment_id(crypto::hash8 &payment_id, const crypto::public_key &public_key, const crypto::secret_key &secret_key)
   {
     // Encryption and decryption are the same operation (xor with a key)
     return encrypt_payment_id(payment_id, public_key, secret_key);
@@ -411,13 +428,12 @@ namespace cryptonote
       tx_extra_nonce extra_nonce;
       if (find_tx_extra_field_by_type(tx_extra_fields, extra_nonce))
       {
-        crypto::hash payment_id = null_hash;
-        bool encrypted;
-        if (get_payment_id_from_tx_extra_nonce(extra_nonce.nonce, payment_id, encrypted) && encrypted)
+        crypto::hash8 payment_id = null_hash8;
+        if (get_encrypted_payment_id_from_tx_extra_nonce(extra_nonce.nonce, payment_id))
         {
           LOG_PRINT_L2("Encrypting payment id " << payment_id);
           crypto::key_derivation derivation;
-          crypto::public_key view_key_pub = get_destination_view_key_pub(destinations);
+          crypto::public_key view_key_pub = get_destination_view_key_pub(destinations, sender_account_keys);
           if (view_key_pub == null_pkey)
           {
             LOG_ERROR("Destinations have to have exactly one output to support encrypted payment ids");
@@ -431,7 +447,7 @@ namespace cryptonote
           }
 
           std::string extra_nonce;
-          set_payment_id_to_tx_extra_nonce(extra_nonce, payment_id, true);
+          set_encrypted_payment_id_to_tx_extra_nonce(extra_nonce, payment_id);
           remove_extra_nonce_tx_extra(tx.extra);
           if (!add_extra_nonce_to_tx_extra(tx.extra, extra_nonce))
           {
diff --git a/src/cryptonote_core/cryptonote_format_utils.h b/src/cryptonote_core/cryptonote_format_utils.h
index 69baa20cf..319205368 100644
--- a/src/cryptonote_core/cryptonote_format_utils.h
+++ b/src/cryptonote_core/cryptonote_format_utils.h
@@ -45,8 +45,8 @@ namespace cryptonote
   bool parse_and_validate_tx_from_blob(const blobdata& tx_blob, transaction& tx, crypto::hash& tx_hash, crypto::hash& tx_prefix_hash);
   bool parse_and_validate_tx_from_blob(const blobdata& tx_blob, transaction& tx);
   bool construct_miner_tx(size_t height, size_t median_size, uint64_t already_generated_coins, size_t current_block_size, uint64_t fee, const account_public_address &miner_address, transaction& tx, const blobdata& extra_nonce = blobdata(), size_t max_outs = 1);
-  bool encrypt_payment_id(crypto::hash &payment_id, const crypto::public_key &public_key, const crypto::secret_key &secret_key);
-  bool decrypt_payment_id(crypto::hash &payment_id, const crypto::public_key &public_key, const crypto::secret_key &secret_key);
+  bool encrypt_payment_id(crypto::hash8 &payment_id, const crypto::public_key &public_key, const crypto::secret_key &secret_key);
+  bool decrypt_payment_id(crypto::hash8 &payment_id, const crypto::public_key &public_key, const crypto::secret_key &secret_key);
 
   struct tx_source_entry
   {
@@ -88,8 +88,10 @@ namespace cryptonote
   bool add_tx_pub_key_to_extra(transaction& tx, const crypto::public_key& tx_pub_key);
   bool add_extra_nonce_to_tx_extra(std::vector<uint8_t>& tx_extra, const blobdata& extra_nonce);
   bool remove_extra_nonce_tx_extra(std::vector<uint8_t>& tx_extra);
-  void set_payment_id_to_tx_extra_nonce(blobdata& extra_nonce, const crypto::hash& payment_id, bool encrypted);
-  bool get_payment_id_from_tx_extra_nonce(const blobdata& extra_nonce, crypto::hash& payment_id, bool &encrypted);
+  void set_payment_id_to_tx_extra_nonce(blobdata& extra_nonce, const crypto::hash& payment_id);
+  void set_encrypted_payment_id_to_tx_extra_nonce(blobdata& extra_nonce, const crypto::hash8& payment_id);
+  bool get_payment_id_from_tx_extra_nonce(const blobdata& extra_nonce, crypto::hash& payment_id);
+  bool get_encrypted_payment_id_from_tx_extra_nonce(const blobdata& extra_nonce, crypto::hash8& payment_id);
   bool is_out_to_acc(const account_keys& acc, const txout_to_key& out_key, const crypto::public_key& tx_pub_key, size_t output_index);
   bool lookup_acc_outs(const account_keys& acc, const transaction& tx, const crypto::public_key& tx_pub_key, std::vector<size_t>& outs, uint64_t& money_transfered);
   bool lookup_acc_outs(const account_keys& acc, const transaction& tx, std::vector<size_t>& outs, uint64_t& money_transfered);