NoteEncryption implementation and integration, removal of ECIES and crypto++ dependencies.

src/zcash/NoteEncryption.hpp

@@ -0,0 +1,79 @@
+/*
+See the Zcash protocol specification for more information.
+https://github.com/zcash/zips/blob/master/protocol/protocol.pdf
+*/
+
+#ifndef ZC_NOTE_ENCRYPTION_H_
+#define ZC_NOTE_ENCRYPTION_H_
+
+#include <boost/array.hpp>
+#include "uint256.h"
+
+#include "zerocash/Zerocash.h"
+
+namespace libzcash {
+
+#define NOTEENCRYPTION_AUTH_BYTES 16
+
+template<size_t MLEN>
+class NoteEncryption {
+protected:
+    enum { CLEN=MLEN+NOTEENCRYPTION_AUTH_BYTES };
+    uint256 epk;
+    uint256 esk;
+    unsigned char nonce;
+    uint256 hSig;
+
+public:
+    typedef boost::array<unsigned char, CLEN> Ciphertext;
+    typedef boost::array<unsigned char, MLEN> Plaintext;
+
+    NoteEncryption(uint256 hSig);
+
+    // Gets the ephemeral public key
+    uint256 get_epk() {
+        return epk;
+    }
+
+    // Encrypts `message` with `pk_enc` and returns the ciphertext.
+    // This can only be called twice for a given instantiation before
+    // the nonce-space runs out.
+    Ciphertext encrypt(const uint256 &pk_enc,
+                       const Plaintext &message
+                      );
+
+    // Creates a NoteEncryption private key
+    static uint256 generate_privkey(const uint256 &a_sk);
+
+    // Creates a NoteEncryption public key from a private key
+    static uint256 generate_pubkey(const uint256 &sk_enc);
+};
+
+template<size_t MLEN>
+class NoteDecryption {
+protected:
+    enum { CLEN=MLEN+NOTEENCRYPTION_AUTH_BYTES };
+    uint256 sk_enc;
+    uint256 pk_enc;
+
+public:
+    typedef boost::array<unsigned char, CLEN> Ciphertext;
+    typedef boost::array<unsigned char, MLEN> Plaintext;
+
+    NoteDecryption(uint256 sk_enc);
+
+    Plaintext decrypt(const Ciphertext &ciphertext,
+                      const uint256 &epk,
+                      const uint256 &hSig,
+                      unsigned char nonce
+                     ) const;
+};
+
+uint256 random_uint256();
+
+}
+
+typedef libzcash::NoteEncryption<ZC_V_SIZE + ZC_RHO_SIZE + ZC_R_SIZE + ZC_MEMO_SIZE> ZCNoteEncryption;
+typedef libzcash::NoteDecryption<ZC_V_SIZE + ZC_RHO_SIZE + ZC_R_SIZE + ZC_MEMO_SIZE> ZCNoteDecryption;
+
+#endif /* ZC_NOTE_ENCRYPTION_H_ */