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librustzcash/zcash_primitives/src/note_encryption.rs

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use blake2_rfc::blake2b::{Blake2b, Blake2bResult};
use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
use crypto_api_chachapoly::{ChaCha20Ietf, ChachaPolyIetf};
use ff::{PrimeField, PrimeFieldRepr};
use pairing::bls12_381::{Bls12, Fr};
use rand::{OsRng, Rng};
use sapling_crypto::{
jubjub::{
edwards,
fs::{Fs, FsRepr},
PrimeOrder, ToUniform, Unknown,
},
primitives::{Diversifier, Note, PaymentAddress},
};
use std::fmt;
use std::str;
use crate::{keys::OutgoingViewingKey, JUBJUB};
pub const KDF_SAPLING_PERSONALIZATION: &'static [u8; 16] = b"Zcash_SaplingKDF";
pub const PRF_OCK_PERSONALIZATION: &'static [u8; 16] = b"Zcash_Derive_ock";
const COMPACT_NOTE_SIZE: usize = (
1 + // version
11 + // diversifier
8 + // value
32
// rcv
);
const NOTE_PLAINTEXT_SIZE: usize = COMPACT_NOTE_SIZE + 512;
const OUT_PLAINTEXT_SIZE: usize = (
32 + // pk_d
32
// esk
);
const ENC_CIPHERTEXT_SIZE: usize = NOTE_PLAINTEXT_SIZE + 16;
const OUT_CIPHERTEXT_SIZE: usize = OUT_PLAINTEXT_SIZE + 16;
/// Format a byte array as a colon-delimited hex string.
///
/// Source: https://github.com/tendermint/signatory
/// License: MIT / Apache 2.0
fn fmt_colon_delimited_hex<B>(f: &mut fmt::Formatter<'_>, bytes: B) -> fmt::Result
where
B: AsRef<[u8]>,
{
let len = bytes.as_ref().len();
for (i, byte) in bytes.as_ref().iter().enumerate() {
write!(f, "{:02x}", byte)?;
if i != len - 1 {
write!(f, ":")?;
}
}
Ok(())
}
#[derive(Clone)]
pub struct Memo([u8; 512]);
impl fmt::Debug for Memo {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "Memo(")?;
match self.to_utf8() {
Some(Ok(memo)) => write!(f, "{}", memo)?,
_ => fmt_colon_delimited_hex(f, &self.0[..])?,
}
write!(f, ")")
}
}
impl Default for Memo {
fn default() -> Self {
// Empty memo field indication per ZIP 302
let mut memo = [0u8; 512];
memo[0] = 0xF6;
Memo(memo)
}
}
impl PartialEq for Memo {
fn eq(&self, rhs: &Memo) -> bool {
&self.0[..] == &rhs.0[..]
}
}
impl Memo {
/// Returns a Memo containing the given slice, appending with zero bytes if necessary,
/// or None if the slice is too long. If the slice is empty, Memo::default() is
/// returned.
pub fn from_bytes(memo: &[u8]) -> Option<Memo> {
if memo.is_empty() {
Some(Memo::default())
} else if memo.len() <= 512 {
let mut data = [0; 512];
data[0..memo.len()].copy_from_slice(memo);
Some(Memo(data))
} else {
// memo is too long
None
}
}
/// Returns a Memo containing the given string, or None if the string is too long.
pub fn from_str(memo: &str) -> Option<Memo> {
Memo::from_bytes(memo.as_bytes())
}
pub fn as_bytes(&self) -> &[u8] {
&self.0[..]
}
/// Returns:
/// - None if the memo is not text
/// - Some(Ok(memo)) if the memo contains a valid UTF8 string
/// - Some(Err(e)) if the memo contains invalid UTF8
pub fn to_utf8(&self) -> Option<Result<String, str::Utf8Error>> {
// Check if it is a text or binary memo
if self.0[0] < 0xF5 {
// Drop trailing zeroes
let mut data = &self.0[..];
while let Some((0, next)) = data.split_last() {
data = next;
}
// Check if it is valid UTF8
Some(str::from_utf8(data).map(|memo| memo.to_owned()))
} else {
None
}
}
}
fn generate_esk() -> Fs {
// create random 64 byte buffer
let mut rng = OsRng::new().expect("should be able to construct RNG");
let mut buffer = [0u8; 64];
for i in 0..buffer.len() {
buffer[i] = rng.gen();
}
// reduce to uniform value
Fs::to_uniform(&buffer[..])
}
pub fn sapling_ka_agree<'a, P>(esk: &Fs, pk_d: &'a P) -> [u8; 32]
where
edwards::Point<Bls12, Unknown>: From<&'a P>,
{
let p: edwards::Point<Bls12, Unknown> = pk_d.into();
// Multiply by 8
let p = p.mul_by_cofactor(&JUBJUB);
// Multiply by esk
let p = p.mul(*esk, &JUBJUB);
// Produce result
let mut result = [0; 32];
p.write(&mut result[..]).expect("length is not 32 bytes");
result
}
fn kdf_sapling(dhsecret: &[u8], epk: &edwards::Point<Bls12, PrimeOrder>) -> Blake2bResult {
let mut input = [0u8; 64];
input[0..32].copy_from_slice(&dhsecret);
epk.write(&mut input[32..64]).unwrap();
let mut h = Blake2b::with_params(32, &[], &[], KDF_SAPLING_PERSONALIZATION);
h.update(&input);
h.finalize()
}
fn prf_ock(
ovk: &OutgoingViewingKey,
cv: &edwards::Point<Bls12, Unknown>,
cmu: &Fr,
epk: &edwards::Point<Bls12, PrimeOrder>,
) -> Blake2bResult {
let mut ock_input = [0u8; 128];
ock_input[0..32].copy_from_slice(&ovk.0);
cv.write(&mut ock_input[32..64]).unwrap();
cmu.into_repr().write_le(&mut ock_input[64..96]).unwrap();
epk.write(&mut ock_input[96..128]).unwrap();
let mut h = Blake2b::with_params(32, &[], &[], PRF_OCK_PERSONALIZATION);
h.update(&ock_input);
h.finalize()
}
pub struct SaplingNoteEncryption {
epk: edwards::Point<Bls12, PrimeOrder>,
esk: Fs,
note: Note<Bls12>,
to: PaymentAddress<Bls12>,
memo: Memo,
ovk: OutgoingViewingKey,
}
impl SaplingNoteEncryption {
pub fn new(
ovk: OutgoingViewingKey,
note: Note<Bls12>,
to: PaymentAddress<Bls12>,
memo: Memo,
) -> SaplingNoteEncryption {
let esk = generate_esk();
let epk = note.g_d.mul(esk, &JUBJUB);
SaplingNoteEncryption {
epk,
esk,
note,
to,
memo,
ovk,
}
}
pub fn esk(&self) -> &Fs {
&self.esk
}
pub fn epk(&self) -> &edwards::Point<Bls12, PrimeOrder> {
&self.epk
}
pub fn encrypt_note_plaintext(&self) -> [u8; ENC_CIPHERTEXT_SIZE] {
let shared_secret = sapling_ka_agree(&self.esk, &self.to.pk_d);
let key = kdf_sapling(&shared_secret, &self.epk);
let mut input = Vec::with_capacity(NOTE_PLAINTEXT_SIZE);
input.push(1);
input.extend_from_slice(&self.to.diversifier.0);
(&mut input)
.write_u64::<LittleEndian>(self.note.value)
.unwrap();
self.note.r.into_repr().write_le(&mut input).unwrap();
input.extend_from_slice(&self.memo.0);
assert_eq!(input.len(), NOTE_PLAINTEXT_SIZE);
let mut output = [0u8; ENC_CIPHERTEXT_SIZE];
assert_eq!(
ChachaPolyIetf::aead_cipher()
.seal_to(&mut output, &input, &[], &key.as_bytes(), &[0u8; 12])
.unwrap(),
ENC_CIPHERTEXT_SIZE
);
output
}
pub fn encrypt_outgoing_plaintext(
&self,
cv: &edwards::Point<Bls12, Unknown>,
cmu: &Fr,
) -> [u8; OUT_CIPHERTEXT_SIZE] {
let key = prf_ock(&self.ovk, &cv, &cmu, &self.epk);
let mut buf = [0u8; OUT_CIPHERTEXT_SIZE];
self.note.pk_d.write(&mut buf[0..32]).unwrap();
self.esk
.into_repr()
.write_le(&mut buf[32..OUT_PLAINTEXT_SIZE])
.unwrap();
assert_eq!(
ChachaPolyIetf::aead_cipher()
.seal(
&mut buf,
OUT_PLAINTEXT_SIZE,
&[],
key.as_bytes(),
&[0u8; 12]
)
.unwrap(),
OUT_CIPHERTEXT_SIZE
);
buf
}
}
fn parse_note_plaintext_minus_memo(
ivk: &Fs,
cmu: &Fr,
plaintext: &[u8],
) -> Option<(Note<Bls12>, PaymentAddress<Bls12>)> {
let mut d = [0u8; 11];
d.copy_from_slice(&plaintext[1..12]);
let v = (&plaintext[12..20]).read_u64::<LittleEndian>().ok()?;
let mut rcm = FsRepr::default();
rcm.read_le(&plaintext[20..COMPACT_NOTE_SIZE]).ok()?;
let rcm = Fs::from_repr(rcm).ok()?;
let diversifier = Diversifier(d);
let pk_d = diversifier
.g_d::<Bls12>(&JUBJUB)?
.mul(ivk.into_repr(), &JUBJUB);
let to = PaymentAddress { pk_d, diversifier };
let note = to.create_note(v, rcm, &JUBJUB).unwrap();
if note.cm(&JUBJUB) != *cmu {
// Published commitment doesn't match calculated commitment
return None;
}
Some((note, to))
}
/// Attempts to decrypt and validate the given `enc_ciphertext` using the given `ivk`.
/// If successful, the corresponding Sapling note and memo are returned, along with the
/// `PaymentAddress` to which the note was sent.
///
/// Implements section 4.17.2 of the Zcash Protocol Specification.
pub fn try_sapling_note_decryption(
ivk: &Fs,
epk: &edwards::Point<Bls12, PrimeOrder>,
cmu: &Fr,
enc_ciphertext: &[u8],
) -> Option<(Note<Bls12>, PaymentAddress<Bls12>, Memo)> {
assert_eq!(enc_ciphertext.len(), ENC_CIPHERTEXT_SIZE);
let shared_secret = sapling_ka_agree(ivk, epk);
let key = kdf_sapling(&shared_secret, &epk);
let mut plaintext = vec![0; ENC_CIPHERTEXT_SIZE];
assert_eq!(
ChachaPolyIetf::aead_cipher()
.open_to(
&mut plaintext,
&enc_ciphertext,
&[],
key.as_bytes(),
&[0u8; 12]
)
.ok()?,
NOTE_PLAINTEXT_SIZE
);
let (note, to) = parse_note_plaintext_minus_memo(ivk, cmu, &plaintext)?;
let mut memo = [0u8; 512];
memo.copy_from_slice(&plaintext[COMPACT_NOTE_SIZE..NOTE_PLAINTEXT_SIZE]);
Some((note, to, Memo(memo)))
}
/// Attempts to decrypt and validate the first 52 bytes of `enc_ciphertext` using the
/// given `ivk`. If successful, the corresponding Sapling note is returned, along with the
/// `PaymentAddress` to which the note was sent.
///
/// Implements the procedure specified in ZIP 307.
pub fn try_sapling_compact_note_decryption(
ivk: &Fs,
epk: &edwards::Point<Bls12, PrimeOrder>,
cmu: &Fr,
enc_ciphertext: &[u8],
) -> Option<(Note<Bls12>, PaymentAddress<Bls12>)> {
assert_eq!(enc_ciphertext.len(), COMPACT_NOTE_SIZE);
let shared_secret = sapling_ka_agree(ivk, epk);
let key = kdf_sapling(&shared_secret, &epk);
// Prefix plaintext with 64 zero-bytes to skip over Poly1305 keying output
const CHACHA20_BLOCK_SIZE: usize = 64;
let mut plaintext = Vec::with_capacity(CHACHA20_BLOCK_SIZE + COMPACT_NOTE_SIZE);
plaintext.extend_from_slice(&[0; CHACHA20_BLOCK_SIZE]);
plaintext.extend_from_slice(&enc_ciphertext[0..COMPACT_NOTE_SIZE]);
assert_eq!(
ChaCha20Ietf::cipher()
.decrypt(
&mut plaintext,
CHACHA20_BLOCK_SIZE + COMPACT_NOTE_SIZE,
key.as_bytes(),
&[0u8; 12],
)
.ok()?,
CHACHA20_BLOCK_SIZE + COMPACT_NOTE_SIZE
);
parse_note_plaintext_minus_memo(ivk, cmu, &plaintext[CHACHA20_BLOCK_SIZE..])
}
/// Attempts to decrypt and validate the given `enc_ciphertext` using the given `ovk`.
/// If successful, the corresponding Sapling note and memo are returned, along with the
/// `PaymentAddress` to which the note was sent.
///
/// Implements section 4.17.3 of the Zcash Protocol Specification.
pub fn try_sapling_output_recovery(
ovk: &OutgoingViewingKey,
cv: &edwards::Point<Bls12, Unknown>,
cmu: &Fr,
epk: &edwards::Point<Bls12, PrimeOrder>,
enc_ciphertext: &[u8],
out_ciphertext: &[u8],
) -> Option<(Note<Bls12>, PaymentAddress<Bls12>, Memo)> {
assert_eq!(enc_ciphertext.len(), ENC_CIPHERTEXT_SIZE);
assert_eq!(out_ciphertext.len(), OUT_CIPHERTEXT_SIZE);
let ock = prf_ock(&ovk, &cv, &cmu, &epk);
let mut op = vec![0; OUT_CIPHERTEXT_SIZE];
assert_eq!(
ChachaPolyIetf::aead_cipher()
.open_to(&mut op, &out_ciphertext, &[], ock.as_bytes(), &[0u8; 12])
.ok()?,
OUT_PLAINTEXT_SIZE
);
let pk_d = edwards::Point::<Bls12, _>::read(&op[0..32], &JUBJUB)
.ok()?
.as_prime_order(&JUBJUB)?;
let mut esk = FsRepr::default();
esk.read_le(&op[32..OUT_PLAINTEXT_SIZE]).ok()?;
let esk = Fs::from_repr(esk).ok()?;
let shared_secret = sapling_ka_agree(&esk, &pk_d);
let key = kdf_sapling(&shared_secret, &epk);
let mut plaintext = vec![0; ENC_CIPHERTEXT_SIZE];
assert_eq!(
ChachaPolyIetf::aead_cipher()
.open_to(
&mut plaintext,
&enc_ciphertext,
&[],
key.as_bytes(),
&[0u8; 12]
)
.ok()?,
NOTE_PLAINTEXT_SIZE
);
let mut d = [0u8; 11];
d.copy_from_slice(&plaintext[1..12]);
let v = (&plaintext[12..20]).read_u64::<LittleEndian>().ok()?;
let mut rcm = FsRepr::default();
rcm.read_le(&plaintext[20..COMPACT_NOTE_SIZE]).ok()?;
let rcm = Fs::from_repr(rcm).ok()?;
let mut memo = [0u8; 512];
memo.copy_from_slice(&plaintext[COMPACT_NOTE_SIZE..NOTE_PLAINTEXT_SIZE]);
let diversifier = Diversifier(d);
if diversifier
.g_d::<Bls12>(&JUBJUB)?
.mul(esk.into_repr(), &JUBJUB)
!= *epk
{
// Published epk doesn't match calculated epk
return None;
}
let to = PaymentAddress { pk_d, diversifier };
let note = to.create_note(v, rcm, &JUBJUB).unwrap();
if note.cm(&JUBJUB) != *cmu {
// Published commitment doesn't match calculated commitment
return None;
}
Some((note, to, Memo(memo)))
}
#[cfg(test)]
mod tests {
use ff::{PrimeField, PrimeFieldRepr};
use pairing::bls12_381::{Bls12, Fr, FrRepr};
use rand::{thread_rng, Rand, Rng};
use sapling_crypto::{
jubjub::{
edwards,
fs::{Fs, FsRepr},
PrimeOrder, Unknown,
},
primitives::{Diversifier, PaymentAddress, ValueCommitment},
};
use super::{
kdf_sapling, prf_ock, sapling_ka_agree, try_sapling_compact_note_decryption,
try_sapling_note_decryption, try_sapling_output_recovery, Memo, SaplingNoteEncryption,
COMPACT_NOTE_SIZE, ENC_CIPHERTEXT_SIZE, OUT_CIPHERTEXT_SIZE,
};
use crate::{keys::OutgoingViewingKey, JUBJUB};
#[test]
fn memo_from_str() {
assert_eq!(
Memo::from_str("").unwrap(),
Memo([
0xf6, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
])
);
assert_eq!(
Memo::from_str(
"thiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiis \
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiis \
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa \
veeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeryyyyyyyyyyyyyyyyyyyyyyyyyy \
looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong \
meeeeeeeeeeeeeeeeeeemooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo \
but it's just short enough"
)
.unwrap(),
Memo([
0x74, 0x68, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69,
0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69,
0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69,
0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69,
0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69,
0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x73, 0x20, 0x69, 0x69, 0x69,
0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69,
0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69,
0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69,
0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69,
0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x69,
0x69, 0x69, 0x69, 0x69, 0x69, 0x69, 0x73, 0x20, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61,
0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61,
0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61,
0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61,
0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61,
0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61, 0x61,
0x61, 0x61, 0x61, 0x61, 0x20, 0x76, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65,
0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65,
0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65,
0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65,
0x65, 0x65, 0x72, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79,
0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79,
0x79, 0x20, 0x6c, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f,
0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f,
0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f,
0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f,
0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f,
0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6e, 0x67, 0x20, 0x6d,
0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65, 0x65,
0x65, 0x65, 0x65, 0x65, 0x65, 0x6d, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f,
0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f,
0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f,
0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f,
0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x6f, 0x20, 0x62, 0x75, 0x74, 0x20,
0x69, 0x74, 0x27, 0x73, 0x20, 0x6a, 0x75, 0x73, 0x74, 0x20, 0x73, 0x68, 0x6f, 0x72,
0x74, 0x20, 0x65, 0x6e, 0x6f, 0x75, 0x67, 0x68
])
);
assert!(Memo::from_str(
"thiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiis \
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiis \
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa \
veeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeryyyyyyyyyyyyyyyyyyyyyyyyyy \
looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong \
meeeeeeeeeeeeeeeeeeemooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo \
but it's now a bit too long"
)
.is_none());
}
#[test]
fn memo_to_utf8() {
let memo = Memo::from_str("Test memo").unwrap();
assert_eq!(memo.to_utf8(), Some(Ok("Test memo".to_owned())));
assert_eq!(Memo::default().to_utf8(), None);
}
fn random_enc_ciphertext(
mut rng: &mut Rng,
) -> (
OutgoingViewingKey,
Fs,
edwards::Point<Bls12, Unknown>,
Fr,
edwards::Point<Bls12, PrimeOrder>,
[u8; ENC_CIPHERTEXT_SIZE],
[u8; OUT_CIPHERTEXT_SIZE],
) {
let diversifier = Diversifier([0; 11]);
let ivk = Fs::rand(&mut rng);
let pk_d = diversifier.g_d::<Bls12>(&JUBJUB).unwrap().mul(ivk, &JUBJUB);
let pa = PaymentAddress { diversifier, pk_d };
// Construct the value commitment for the proof instance
let value = 100;
let value_commitment = ValueCommitment::<Bls12> {
value,
randomness: Fs::rand(&mut rng),
};
let cv = value_commitment.cm(&JUBJUB).into();
let note = pa.create_note(value, Fs::rand(&mut rng), &JUBJUB).unwrap();
let cmu = note.cm(&JUBJUB);
let ovk = OutgoingViewingKey([0; 32]);
let ne = SaplingNoteEncryption::new(ovk, note, pa, Memo([0; 512]));
let epk = ne.epk();
let enc_ciphertext = ne.encrypt_note_plaintext();
let out_ciphertext = ne.encrypt_outgoing_plaintext(&cv, &cmu);
assert!(try_sapling_note_decryption(&ivk, epk, &cmu, &enc_ciphertext).is_some());
assert!(try_sapling_compact_note_decryption(
&ivk,
epk,
&cmu,
&enc_ciphertext[..COMPACT_NOTE_SIZE]
)
.is_some());
assert!(try_sapling_output_recovery(
&ovk,
&cv,
&cmu,
&epk,
&enc_ciphertext,
&out_ciphertext
)
.is_some());
(
ovk,
ivk,
cv,
cmu,
epk.clone(),
enc_ciphertext,
out_ciphertext,
)
}
#[test]
fn decryption_with_invalid_ivk() {
let mut rng = thread_rng();
let (_, _, _, cmu, epk, enc_ciphertext, _) = random_enc_ciphertext(&mut rng);
assert_eq!(
try_sapling_note_decryption(&Fs::rand(&mut rng), &epk, &cmu, &enc_ciphertext),
None
);
}
#[test]
fn decryption_with_invalid_epk() {
let mut rng = thread_rng();
let (_, ivk, _, cmu, _, enc_ciphertext, _) = random_enc_ciphertext(&mut rng);
assert_eq!(
try_sapling_note_decryption(
&ivk,
&edwards::Point::<Bls12, _>::rand(&mut rng, &JUBJUB).mul_by_cofactor(&JUBJUB),
&cmu,
&enc_ciphertext
),
None
);
}
#[test]
fn decryption_with_invalid_cmu() {
let mut rng = thread_rng();
let (_, ivk, _, _, epk, enc_ciphertext, _) = random_enc_ciphertext(&mut rng);
assert_eq!(
try_sapling_note_decryption(&ivk, &epk, &Fr::rand(&mut rng), &enc_ciphertext),
None
);
}
#[test]
fn decryption_with_invalid_tag() {
let mut rng = thread_rng();
let (_, ivk, _, cmu, epk, mut enc_ciphertext, _) = random_enc_ciphertext(&mut rng);
enc_ciphertext[ENC_CIPHERTEXT_SIZE - 1] ^= 0xff;
assert_eq!(
try_sapling_note_decryption(&ivk, &epk, &cmu, &enc_ciphertext),
None
);
}
#[test]
fn compact_decryption_with_invalid_ivk() {
let mut rng = thread_rng();
let (_, _, _, cmu, epk, enc_ciphertext, _) = random_enc_ciphertext(&mut rng);
assert_eq!(
try_sapling_compact_note_decryption(
&Fs::rand(&mut rng),
&epk,
&cmu,
&enc_ciphertext[..COMPACT_NOTE_SIZE]
),
None
);
}
#[test]
fn compact_decryption_with_invalid_epk() {
let mut rng = thread_rng();
let (_, ivk, _, cmu, _, enc_ciphertext, _) = random_enc_ciphertext(&mut rng);
assert_eq!(
try_sapling_compact_note_decryption(
&ivk,
&edwards::Point::<Bls12, _>::rand(&mut rng, &JUBJUB).mul_by_cofactor(&JUBJUB),
&cmu,
&enc_ciphertext[..COMPACT_NOTE_SIZE]
),
None
);
}
#[test]
fn compact_decryption_with_invalid_cmu() {
let mut rng = thread_rng();
let (_, ivk, _, _, epk, enc_ciphertext, _) = random_enc_ciphertext(&mut rng);
assert_eq!(
try_sapling_compact_note_decryption(
&ivk,
&epk,
&Fr::rand(&mut rng),
&enc_ciphertext[..COMPACT_NOTE_SIZE]
),
None
);
}
#[test]
fn compact_decryption_with_invalid_diversifier() {
let mut rng = thread_rng();
let (_, ivk, _, cmu, epk, mut enc_ciphertext, _) = random_enc_ciphertext(&mut rng);
// In compact decryption, this will result in an altered diversifier
enc_ciphertext[1] ^= 0xff;
assert_eq!(
try_sapling_compact_note_decryption(
&ivk,
&epk,
&cmu,
&enc_ciphertext[..COMPACT_NOTE_SIZE]
),
None
);
}
#[test]
fn recovery_with_invalid_ovk() {
let mut rng = thread_rng();
let (mut ovk, _, cv, cmu, epk, enc_ciphertext, out_ciphertext) =
random_enc_ciphertext(&mut rng);
ovk.0[0] ^= 0xff;
assert_eq!(
try_sapling_output_recovery(&ovk, &cv, &cmu, &epk, &enc_ciphertext, &out_ciphertext),
None
);
}
#[test]
fn recovery_with_invalid_cv() {
let mut rng = thread_rng();
let (ovk, _, _, cmu, epk, enc_ciphertext, out_ciphertext) = random_enc_ciphertext(&mut rng);
assert_eq!(
try_sapling_output_recovery(
&ovk,
&edwards::Point::<Bls12, _>::rand(&mut rng, &JUBJUB),
&cmu,
&epk,
&enc_ciphertext,
&out_ciphertext
),
None
);
}
#[test]
fn recovery_with_invalid_cmu() {
let mut rng = thread_rng();
let (ovk, _, cv, _, epk, enc_ciphertext, out_ciphertext) = random_enc_ciphertext(&mut rng);
assert_eq!(
try_sapling_output_recovery(
&ovk,
&cv,
&Fr::rand(&mut rng),
&epk,
&enc_ciphertext,
&out_ciphertext
),
None
);
}
#[test]
fn recovery_with_invalid_epk() {
let mut rng = thread_rng();
let (ovk, _, cv, cmu, _, enc_ciphertext, out_ciphertext) = random_enc_ciphertext(&mut rng);
assert_eq!(
try_sapling_output_recovery(
&ovk,
&cv,
&cmu,
&edwards::Point::<Bls12, _>::rand(&mut rng, &JUBJUB).mul_by_cofactor(&JUBJUB),
&enc_ciphertext,
&out_ciphertext
),
None
);
}
#[test]
fn recovery_with_invalid_enc_tag() {
let mut rng = thread_rng();
let (ovk, _, cv, cmu, epk, mut enc_ciphertext, out_ciphertext) =
random_enc_ciphertext(&mut rng);
enc_ciphertext[ENC_CIPHERTEXT_SIZE - 1] ^= 0xff;
assert_eq!(
try_sapling_output_recovery(&ovk, &cv, &cmu, &epk, &enc_ciphertext, &out_ciphertext),
None
);
}
#[test]
fn recovery_with_invalid_out_tag() {
let mut rng = thread_rng();
let (ovk, _, cv, cmu, epk, enc_ciphertext, mut out_ciphertext) =
random_enc_ciphertext(&mut rng);
out_ciphertext[OUT_CIPHERTEXT_SIZE - 1] ^= 0xff;
assert_eq!(
try_sapling_output_recovery(&ovk, &cv, &cmu, &epk, &enc_ciphertext, &out_ciphertext),
None
);
}
#[test]
fn test_vectors() {
let test_vectors = crate::test_vectors::note_encryption::make_test_vectors();
macro_rules! read_fr {
($field:expr) => {{
let mut repr = FrRepr::default();
repr.read_le(&$field[..]).unwrap();
Fr::from_repr(repr).unwrap()
}};
}
macro_rules! read_fs {
($field:expr) => {{
let mut repr = FsRepr::default();
repr.read_le(&$field[..]).unwrap();
Fs::from_repr(repr).unwrap()
}};
}
macro_rules! read_point {
($field:expr) => {
edwards::Point::<Bls12, _>::read(&$field[..], &JUBJUB).unwrap()
};
}
for tv in test_vectors {
//
// Load the test vector components
//
let ivk = read_fs!(tv.ivk);
let pk_d = read_point!(tv.default_pk_d)
.as_prime_order(&JUBJUB)
.unwrap();
let rcm = read_fs!(tv.rcm);
let cv = read_point!(tv.cv);
let cmu = read_fr!(tv.cmu);
let esk = read_fs!(tv.esk);
let epk = read_point!(tv.epk).as_prime_order(&JUBJUB).unwrap();
//
// Test the individual components
//
let shared_secret = sapling_ka_agree(&esk, &pk_d);
assert_eq!(shared_secret, tv.shared_secret);
let k_enc = kdf_sapling(&shared_secret, &epk);
assert_eq!(k_enc.as_bytes(), tv.k_enc);
let ovk = OutgoingViewingKey(tv.ovk);
let ock = prf_ock(&ovk, &cv, &cmu, &epk);
assert_eq!(ock.as_bytes(), tv.ock);
let to = PaymentAddress {
pk_d,
diversifier: Diversifier(tv.default_d),
};
let note = to.create_note(tv.v, rcm, &JUBJUB).unwrap();
assert_eq!(note.cm(&JUBJUB), cmu);
//
// Test decryption
// (Tested first because it only requires immutable references.)
//
match try_sapling_note_decryption(&ivk, &epk, &cmu, &tv.c_enc) {
Some((decrypted_note, decrypted_to, decrypted_memo)) => {
assert_eq!(decrypted_note, note);
assert_eq!(decrypted_to, to);
assert_eq!(&decrypted_memo.0[..], &tv.memo[..]);
}
None => panic!("Note decryption failed"),
}
match try_sapling_compact_note_decryption(
&ivk,
&epk,
&cmu,
&tv.c_enc[..COMPACT_NOTE_SIZE],
) {
Some((decrypted_note, decrypted_to)) => {
assert_eq!(decrypted_note, note);
assert_eq!(decrypted_to, to);
}
None => panic!("Compact note decryption failed"),
}
match try_sapling_output_recovery(&ovk, &cv, &cmu, &epk, &tv.c_enc, &tv.c_out) {
Some((decrypted_note, decrypted_to, decrypted_memo)) => {
assert_eq!(decrypted_note, note);
assert_eq!(decrypted_to, to);
assert_eq!(&decrypted_memo.0[..], &tv.memo[..]);
}
None => panic!("Output recovery failed"),
}
//
// Test encryption
//
let mut ne = SaplingNoteEncryption::new(ovk, note, to, Memo(tv.memo));
// Swap in the ephemeral keypair from the test vectors
ne.esk = esk;
ne.epk = epk;
assert_eq!(&ne.encrypt_note_plaintext()[..], &tv.c_enc[..]);
assert_eq!(&ne.encrypt_outgoing_plaintext(&cv, &cmu)[..], &tv.c_out[..]);
}
}
}