Arbitrary M/N multisig schemes:

* support in wallet2
* support in monero-wallet-cli
* support in monero-wallet-rpc
* support in wallet api
* support in monero-gen-trusted-multisig
* unit tests for multisig wallets creation

1 files changed, 23 insertions, 1 deletions

diff --git a/src/multisig/multisig.h b/src/multisig/multisig.h
index f95611441..93a756812 100644
--- a/src/multisig/multisig.h
+++ b/src/multisig/multisig.h
@@ -41,9 +41,31 @@ namespace cryptonote
   crypto::secret_key get_multisig_blinded_secret_key(const crypto::secret_key &key);
   void generate_multisig_N_N(const account_keys &keys, const std::vector<crypto::public_key> &spend_keys, std::vector<crypto::secret_key> &multisig_keys, rct::key &spend_skey, rct::key &spend_pkey);
   void generate_multisig_N1_N(const account_keys &keys, const std::vector<crypto::public_key> &spend_keys, std::vector<crypto::secret_key> &multisig_keys, rct::key &spend_skey, rct::key &spend_pkey);
+  /**
+   * @brief generate_multisig_derivations performs common DH key derivation.
+   *    Each middle round in M/N scheme is DH exchange of public multisig keys of other participants multiplied by secret spend key of current participant.
+   *    this functions does the following: new multisig key = secret spend * public multisig key
+   * @param keys - current wallet's keys
+   * @param derivations - public multisig keys of other participants
+   * @return new public multisig keys derived from previous round. This data needs to be exchange with other participants
+   */
+  std::vector<crypto::public_key> generate_multisig_derivations(const account_keys &keys, const std::vector<crypto::public_key> &derivations);
+  crypto::secret_key calculate_multisig_signer_key(const std::vector<crypto::secret_key>& derivations);
+  /**
+   * @brief calculate_multisig_keys. Calculates secret multisig keys from others' participants ones as follows: mi = H(Mi)
+   * @param derivations - others' participants public multisig keys.
+   * @return vector of current wallet's multisig secret keys
+   */
+  std::vector<crypto::secret_key> calculate_multisig_keys(const std::vector<crypto::public_key>& derivations);
   crypto::secret_key generate_multisig_view_secret_key(const crypto::secret_key &skey, const std::vector<crypto::secret_key> &skeys);
-  crypto::public_key generate_multisig_N1_N_spend_public_key(const std::vector<crypto::public_key> &pkeys);
+  /**
+   * @brief generate_multisig_M_N_spend_public_key calculates multisig wallet's spend public key by summing all of public multisig keys
+   * @param pkeys unique public multisig keys
+   * @return multisig wallet's spend public key
+   */
+  crypto::public_key generate_multisig_M_N_spend_public_key(const std::vector<crypto::public_key> &pkeys);
   bool generate_multisig_key_image(const account_keys &keys, size_t multisig_key_index, const crypto::public_key& out_key, crypto::key_image& ki);
   void generate_multisig_LR(const crypto::public_key pkey, const crypto::secret_key &k, crypto::public_key &L, crypto::public_key &R);
   bool generate_multisig_composite_key_image(const account_keys &keys, const std::unordered_map<crypto::public_key, cryptonote::subaddress_index>& subaddresses, const crypto::public_key& out_key, const crypto::public_key &tx_public_key, const std::vector<crypto::public_key>& additional_tx_public_keys, size_t real_output_index, const std::vector<crypto::key_image> &pkis, crypto::key_image &ki);
+  uint32_t multisig_rounds_required(uint32_t participants, uint32_t threshold);
 }