1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50

// Copyright (C) 2019-2022 Aleo Systems Inc.
// This file is part of the snarkVM library.

// The snarkVM library is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// The snarkVM library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with the snarkVM library. If not, see <https://www.gnu.org/licenses/>.

use super::*;

impl<N: Network> Plaintext<N> {
    /// Encrypts `self` to the given address under the given randomizer.
    pub fn encrypt(&self, address: &Address<N>, randomizer: Scalar<N>) -> Result<Ciphertext<N>> {
        // Compute the plaintext view key.
        let plaintext_view_key = (**address * randomizer).to_x_coordinate();
        // Encrypt the plaintext.
        self.encrypt_symmetric(plaintext_view_key)
    }

    /// Encrypts `self` under the given plaintext view key.
    pub fn encrypt_symmetric(&self, plaintext_view_key: Field<N>) -> Result<Ciphertext<N>> {
        // Determine the number of randomizers needed to encrypt the plaintext.
        let num_randomizers = self.num_randomizers()?;
        // Prepare a randomizer for each field element.
        let randomizers = N::hash_many_psd8(&[N::encryption_domain(), plaintext_view_key], num_randomizers);
        // Encrypt the plaintext.
        self.encrypt_with_randomizers(&randomizers)
    }

    /// Encrypts `self` under the given randomizers.
    pub(crate) fn encrypt_with_randomizers(&self, randomizers: &[Field<N>]) -> Result<Ciphertext<N>> {
        // Encrypt the plaintext.
        Ciphertext::from_fields(
            &self
                .to_fields()?
                .into_iter()
                .zip_eq(randomizers)
                .map(|(plaintext, randomizer)| plaintext + randomizer)
                .collect::<Vec<_>>(),
        )
    }
}