zcash_primitives: Add OutgoingCipherKey struct
This commit is contained in:
Jack Grigg
parent
50140c521a
commit
72817b0edc
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@ -152,6 +152,21 @@ fn kdf_sapling(dhsecret: jubjub::SubgroupPoint, epk: &jubjub::SubgroupPoint) ->
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.finalize()
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}
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/// A symmetric key that can be used to recover a single Sapling output.
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pub struct OutgoingCipherKey([u8; 32]);
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impl From<[u8; 32]> for OutgoingCipherKey {
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fn from(ock: [u8; 32]) -> Self {
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OutgoingCipherKey(ock)
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}
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}
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impl AsRef<[u8]> for OutgoingCipherKey {
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fn as_ref(&self) -> &[u8] {
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&self.0
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}
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}
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/// Sapling PRF^ock.
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///
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/// Implemented per section 5.4.2 of the Zcash Protocol Specification.
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@ -160,16 +175,21 @@ pub fn prf_ock(
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cv: &jubjub::ExtendedPoint,
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cmu: &bls12_381::Scalar,
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epk: &jubjub::SubgroupPoint,
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) -> Blake2bHash {
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Blake2bParams::new()
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.hash_length(32)
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.personal(PRF_OCK_PERSONALIZATION)
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.to_state()
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.update(&ovk.0)
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.update(&cv.to_bytes())
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.update(&cmu.to_repr())
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.update(&epk.to_bytes())
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.finalize()
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) -> OutgoingCipherKey {
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OutgoingCipherKey(
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Blake2bParams::new()
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.hash_length(32)
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.personal(PRF_OCK_PERSONALIZATION)
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.to_state()
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.update(&ovk.0)
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.update(&cv.to_bytes())
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.update(&cmu.to_repr())
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.update(&epk.to_bytes())
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.finalize()
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.as_bytes()
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.try_into()
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.unwrap(),
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)
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}
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/// An API for encrypting Sapling notes.
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@ -301,7 +321,7 @@ impl SaplingNoteEncryption {
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cv: &jubjub::ExtendedPoint,
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cmu: &bls12_381::Scalar,
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) -> [u8; OUT_CIPHERTEXT_SIZE] {
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let key = prf_ock(&self.ovk, &cv, &cmu, &self.epk);
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let ock = prf_ock(&self.ovk, &cv, &cmu, &self.epk);
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let mut input = [0u8; OUT_PLAINTEXT_SIZE];
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input[0..32].copy_from_slice(&self.note.pk_d.to_bytes());
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@ -310,7 +330,7 @@ impl SaplingNoteEncryption {
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let mut output = [0u8; OUT_CIPHERTEXT_SIZE];
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assert_eq!(
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ChachaPolyIetf::aead_cipher()
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.seal_to(&mut output, &input, &[], key.as_bytes(), &[0u8; 12])
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.seal_to(&mut output, &input, &[], ock.as_ref(), &[0u8; 12])
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.unwrap(),
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OUT_CIPHERTEXT_SIZE
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);
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@ -468,7 +488,7 @@ pub fn try_sapling_compact_note_decryption<P: consensus::Parameters>(
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/// For decryption using a Full Viewing Key see [`try_sapling_output_recovery`].
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pub fn try_sapling_output_recovery_with_ock<P: consensus::Parameters>(
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height: u32,
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ock: &[u8],
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ock: &OutgoingCipherKey,
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cmu: &bls12_381::Scalar,
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epk: &jubjub::SubgroupPoint,
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enc_ciphertext: &[u8],
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@ -480,7 +500,7 @@ pub fn try_sapling_output_recovery_with_ock<P: consensus::Parameters>(
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let mut op = [0; OUT_CIPHERTEXT_SIZE];
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assert_eq!(
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ChachaPolyIetf::aead_cipher()
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.open_to(&mut op, &out_ciphertext, &[], &ock, &[0u8; 12])
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.open_to(&mut op, &out_ciphertext, &[], ock.as_ref(), &[0u8; 12])
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.ok()?,
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OUT_PLAINTEXT_SIZE
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);
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@ -583,7 +603,7 @@ pub fn try_sapling_output_recovery<P: consensus::Parameters>(
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) -> Option<(Note, PaymentAddress, Memo)> {
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try_sapling_output_recovery_with_ock::<P>(
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height,
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prf_ock(&ovk, &cv, &cmu, &epk).as_bytes(),
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&prf_ock(&ovk, &cv, &cmu, &epk),
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cmu,
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epk,
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enc_ciphertext,
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@ -593,7 +613,6 @@ pub fn try_sapling_output_recovery<P: consensus::Parameters>(
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#[cfg(test)]
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mod tests {
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use blake2b_simd::Hash as Blake2bHash;
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use crypto_api_chachapoly::ChachaPolyIetf;
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use ff::{Field, PrimeField};
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use group::Group;
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@ -606,8 +625,9 @@ mod tests {
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use super::{
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kdf_sapling, prf_ock, sapling_ka_agree, try_sapling_compact_note_decryption,
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try_sapling_note_decryption, try_sapling_output_recovery,
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try_sapling_output_recovery_with_ock, Memo, SaplingNoteEncryption, COMPACT_NOTE_SIZE,
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ENC_CIPHERTEXT_SIZE, NOTE_PLAINTEXT_SIZE, OUT_CIPHERTEXT_SIZE, OUT_PLAINTEXT_SIZE,
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try_sapling_output_recovery_with_ock, Memo, OutgoingCipherKey, SaplingNoteEncryption,
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COMPACT_NOTE_SIZE, ENC_CIPHERTEXT_SIZE, NOTE_PLAINTEXT_SIZE, OUT_CIPHERTEXT_SIZE,
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OUT_PLAINTEXT_SIZE,
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};
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use crate::{
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consensus::{
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@ -741,7 +761,7 @@ mod tests {
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mut rng: &mut R,
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) -> (
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OutgoingViewingKey,
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Blake2bHash,
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OutgoingCipherKey,
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jubjub::Fr,
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jubjub::ExtendedPoint,
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bls12_381::Scalar,
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@ -782,7 +802,7 @@ mod tests {
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);
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let ock_output_recovery = try_sapling_output_recovery_with_ock::<TestNetwork>(
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height,
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ock.as_bytes(),
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&ock,
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&cmu,
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&epk,
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&enc_ciphertext,
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@ -801,7 +821,7 @@ mod tests {
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mut rng: &mut R,
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) -> (
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OutgoingViewingKey,
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Blake2bHash,
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OutgoingCipherKey,
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jubjub::Fr,
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jubjub::ExtendedPoint,
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bls12_381::Scalar,
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@ -859,7 +879,7 @@ mod tests {
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let mut op = [0; OUT_CIPHERTEXT_SIZE];
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assert_eq!(
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ChachaPolyIetf::aead_cipher()
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.open_to(&mut op, out_ciphertext, &[], ock.as_bytes(), &[0u8; 12])
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.open_to(&mut op, out_ciphertext, &[], ock.as_ref(), &[0u8; 12])
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.unwrap(),
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OUT_PLAINTEXT_SIZE
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);
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@ -1351,7 +1371,7 @@ mod tests {
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assert_eq!(
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try_sapling_output_recovery_with_ock::<TestNetwork>(
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height,
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&[0u8; 32],
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&OutgoingCipherKey([0u8; 32]),
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&cmu,
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&epk,
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&enc_ciphertext,
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@ -1416,7 +1436,7 @@ mod tests {
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assert_eq!(
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try_sapling_output_recovery_with_ock::<TestNetwork>(
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height,
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&ock.as_bytes(),
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&ock,
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&bls12_381::Scalar::random(&mut rng),
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&epk,
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&enc_ctext,
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@ -1454,7 +1474,7 @@ mod tests {
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assert_eq!(
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try_sapling_output_recovery_with_ock::<TestNetwork>(
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height,
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&ock.as_bytes(),
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&ock,
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&cmu,
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&jubjub::SubgroupPoint::random(&mut rng),
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&enc_ciphertext,
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@ -1493,7 +1513,7 @@ mod tests {
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assert_eq!(
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try_sapling_output_recovery_with_ock::<TestNetwork>(
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height,
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&ock.as_bytes(),
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&ock,
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&cmu,
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&epk,
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&enc_ciphertext,
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@ -1532,7 +1552,7 @@ mod tests {
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assert_eq!(
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try_sapling_output_recovery_with_ock::<TestNetwork>(
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height,
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&ock.as_bytes(),
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&ock,
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&cmu,
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&epk,
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&enc_ciphertext,
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@ -1582,7 +1602,7 @@ mod tests {
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assert_eq!(
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try_sapling_output_recovery_with_ock::<TestNetwork>(
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height,
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&ock.as_bytes(),
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&ock,
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&cmu,
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&epk,
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&enc_ciphertext,
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@ -1629,7 +1649,7 @@ mod tests {
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assert_eq!(
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try_sapling_output_recovery_with_ock::<TestNetwork>(
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height,
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&ock.as_bytes(),
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&ock,
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&cmu,
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&epk,
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&enc_ciphertext,
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@ -1676,7 +1696,7 @@ mod tests {
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assert_eq!(
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try_sapling_output_recovery_with_ock::<TestNetwork>(
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height,
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&ock.as_bytes(),
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&ock,
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&cmu,
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&epk,
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&enc_ciphertext,
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@ -1715,7 +1735,7 @@ mod tests {
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assert_eq!(
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try_sapling_output_recovery_with_ock::<TestNetwork>(
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height,
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&ock.as_bytes(),
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&ock,
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&cmu,
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&epk,
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&enc_ciphertext,
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@ -1776,7 +1796,7 @@ mod tests {
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let ovk = OutgoingViewingKey(tv.ovk);
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let ock = prf_ock(&ovk, &cv, &cmu, &epk);
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assert_eq!(ock.as_bytes(), tv.ock);
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assert_eq!(ock.as_ref(), tv.ock);
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let to = PaymentAddress::from_parts(Diversifier(tv.default_d), pk_d).unwrap();
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let note = to.create_note(tv.v, Rseed::BeforeZip212(rcm)).unwrap();
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