noteencryption.h

Go to the documentation of this file.

// Copyright (c) 2016-2020 The ZCash developers
// Copyright (c) 2021 The PIVX Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or https://www.opensource.org/licenses/mit-license.php.
 
/*
See the Zcash protocol specification for more information.
https://github.com/zcash/zips/blob/master/protocol/protocol.pdf
*/
 
#ifndef PIVX_SAPLING_NOTEENCRYPTION_H
#define PIVX_SAPLING_NOTEENCRYPTION_H
 
#include "optional.h"
#include "sapling/sapling.h"
#include "uint256.h"
 
#include <array>
 
namespace libzcash {
 
// Ciphertext for the recipient to decrypt
typedef std::array<unsigned char, ZC_SAPLING_ENCCIPHERTEXT_SIZE> SaplingEncCiphertext;
typedef std::array<unsigned char, ZC_SAPLING_ENCPLAINTEXT_SIZE> SaplingEncPlaintext;
 
// Ciphertext for outgoing viewing key to decrypt
typedef std::array<unsigned char, ZC_SAPLING_OUTCIPHERTEXT_SIZE> SaplingOutCiphertext;
typedef std::array<unsigned char, ZC_SAPLING_OUTPLAINTEXT_SIZE> SaplingOutPlaintext;
 
class SaplingNoteEncryption {
protected:
    // Ephemeral public key
    uint256 epk;
 
    // Ephemeral secret key
    uint256 esk;
 
    bool already_encrypted_enc;
    bool already_encrypted_out;
 
    SaplingNoteEncryption(uint256 epk, uint256 esk) : epk(epk), esk(esk), already_encrypted_enc(false), already_encrypted_out(false) {
 
    }
 
public:
 
    static Optional<SaplingNoteEncryption> FromDiversifier(diversifier_t d);
 
    Optional<SaplingEncCiphertext> encrypt_to_recipient(
        const uint256 &pk_d,
        const SaplingEncPlaintext &message
    );
 
    SaplingOutCiphertext encrypt_to_ourselves(
        const uint256 &ovk,
        const uint256 &cv,
        const uint256 &cm,
        const SaplingOutPlaintext &message
    );
 
    uint256 get_epk() const {
        return epk;
    }
 
    uint256 get_esk() const {
        return esk;
    }
};
 
// Attempts to decrypt a Sapling note. This will not check that the contents
// of the ciphertext are correct.
Optional<SaplingEncPlaintext> AttemptSaplingEncDecryption(
    const SaplingEncCiphertext &ciphertext,
    const uint256 &ivk,
    const uint256 &epk
);
 
// Attempts to decrypt a Sapling note using outgoing plaintext.
// This will not check that the contents of the ciphertext are correct.
Optional<SaplingEncPlaintext> AttemptSaplingEncDecryption (
    const SaplingEncCiphertext &ciphertext,
    const uint256 &epk,
    const uint256 &esk,
    const uint256 &pk_d
);
 
// Attempts to decrypt a Sapling note. This will not check that the contents
// of the ciphertext are correct.
Optional<SaplingOutPlaintext> AttemptSaplingOutDecryption(
    const SaplingOutCiphertext &ciphertext,
    const uint256 &ovk,
    const uint256 &cv,
    const uint256 &cm,
    const uint256 &epk
);
 
}
 
#endif // PIVX_SAPLING_NOTEENCRYPTION_H