Signature proving payment to destination by only revealing key derivation, not the actual tx secret key

1 files changed, 14 insertions, 0 deletions

diff --git a/src/crypto/crypto.h b/src/crypto/crypto.h
index 3b8c7996b..e99b6651f 100644
--- a/src/crypto/crypto.h
+++ b/src/crypto/crypto.h
@@ -123,6 +123,10 @@ namespace crypto {
     friend void generate_signature(const hash &, const public_key &, const secret_key &, signature &);
     static bool check_signature(const hash &, const public_key &, const signature &);
     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 public_key &, const secret_key &, signature &);
+    friend void generate_tx_proof(const hash &, const public_key &, const public_key &, const public_key &, const secret_key &, signature &);
+    static bool check_tx_proof(const hash &, const public_key &, const public_key &, const public_key &, const signature &);
+    friend bool check_tx_proof(const hash &, const public_key &, const public_key &, const public_key &, const signature &);
     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 &,
@@ -200,6 +204,16 @@ namespace crypto {
     return crypto_ops::check_signature(prefix_hash, pub, sig);
   }
 
+  /* Generation and checking of a tx proof; given a tx pubkey R, the recipient's view pubkey A, and the key 
+   * derivation D, the signature proves the knowledge of the tx secret key r such that R=r*G and D=r*A
+   */
+  inline void generate_tx_proof(const hash &prefix_hash, const public_key &R, const public_key &A, const public_key &D, const secret_key &r, signature &sig) {
+    crypto_ops::generate_tx_proof(prefix_hash, R, A, D, r, sig);
+  }
+  inline bool check_tx_proof(const hash &prefix_hash, const public_key &R, const public_key &A, const public_key &D, const signature &sig) {
+    return crypto_ops::check_tx_proof(prefix_hash, R, A, D, sig);
+  }
+
   /* To send money to a key:
    * * The sender generates an ephemeral key and includes it in transaction output.
    * * To spend the money, the receiver generates a key image from it.