diff --git a/src/test_vectors.rs b/src/test_vectors.rs index 042f3b913..b1ef91eec 100644 --- a/src/test_vectors.rs +++ b/src/test_vectors.rs @@ -2,3 +2,4 @@ pub(crate) mod commitment_tree; pub(crate) mod keys; pub(crate) mod merkle_path; pub(crate) mod note_encryption; +pub(crate) mod zip32; diff --git a/src/test_vectors/zip32.rs b/src/test_vectors/zip32.rs new file mode 100644 index 000000000..755294dc9 --- /dev/null +++ b/src/test_vectors/zip32.rs @@ -0,0 +1,112 @@ +//! Test vectors for Orchard ZIP 32 key derivation. + +pub(crate) struct TestVector { + pub(crate) sk: [u8; 32], + pub(crate) c: [u8; 32], + pub(crate) xsk: [u8; 73], + pub(crate) fp: [u8; 32], +} + +// From https://github.com/zcash-hackworks/zcash-test-vectors/blob/master/orchard_zip32.py +pub(crate) const TEST_VECTORS: &[TestVector] = &[ + TestVector { + sk: [ + 0x7e, 0xee, 0x3c, 0x10, 0x17, 0x87, 0x09, 0x90, 0xa3, 0xdd, 0x68, 0x91, 0xb8, 0x2f, + 0x80, 0xbe, 0x89, 0x76, 0xc1, 0xe7, 0xdc, 0x20, 0xd6, 0x08, 0x17, 0xa5, 0xe8, 0x8e, + 0x8b, 0x2c, 0xd4, 0xb8, + ], + c: [ + 0xab, 0x8b, 0x7a, 0x00, 0x50, 0x9e, 0xf2, 0x0e, 0x46, 0x9b, 0x52, 0x92, 0xb6, 0x1d, + 0x47, 0x4b, 0x7c, 0xff, 0xcb, 0x16, 0x57, 0x92, 0x4c, 0xda, 0x72, 0x02, 0x50, 0xae, + 0x40, 0x52, 0x66, 0x77, + ], + xsk: [ + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xab, 0x8b, 0x7a, 0x00, 0x50, + 0x9e, 0xf2, 0x0e, 0x46, 0x9b, 0x52, 0x92, 0xb6, 0x1d, 0x47, 0x4b, 0x7c, 0xff, 0xcb, + 0x16, 0x57, 0x92, 0x4c, 0xda, 0x72, 0x02, 0x50, 0xae, 0x40, 0x52, 0x66, 0x77, 0x7e, + 0xee, 0x3c, 0x10, 0x17, 0x87, 0x09, 0x90, 0xa3, 0xdd, 0x68, 0x91, 0xb8, 0x2f, 0x80, + 0xbe, 0x89, 0x76, 0xc1, 0xe7, 0xdc, 0x20, 0xd6, 0x08, 0x17, 0xa5, 0xe8, 0x8e, 0x8b, + 0x2c, 0xd4, 0xb8, + ], + fp: [ + 0xff, 0x4c, 0xda, 0x50, 0x02, 0xc8, 0xd1, 0x82, 0x05, 0x88, 0x07, 0xb8, 0x4e, 0x61, + 0x6b, 0x6d, 0x33, 0x9e, 0x1b, 0xbe, 0xec, 0xea, 0x01, 0x65, 0x05, 0x68, 0xd8, 0x91, + 0xa4, 0x38, 0xe7, 0x06, + ], + }, + TestVector { + sk: [ + 0x98, 0xd7, 0x03, 0xfc, 0xb4, 0x05, 0x04, 0xc9, 0x5b, 0x3b, 0x6e, 0xd1, 0x0e, 0xcd, + 0x50, 0x08, 0x2c, 0xff, 0x97, 0xdf, 0xd1, 0xdd, 0x9a, 0xa0, 0x91, 0x3c, 0x78, 0xf9, + 0x77, 0xc9, 0x62, 0xaf, + ], + c: [ + 0x6a, 0x04, 0x1d, 0xfb, 0x9c, 0xfe, 0xbe, 0xe9, 0x7c, 0xb1, 0x85, 0x4f, 0xdc, 0x48, + 0x1c, 0xc0, 0x4f, 0x02, 0xc9, 0x57, 0x7a, 0xa6, 0xf1, 0x3b, 0x2c, 0x44, 0x5b, 0x80, + 0xa9, 0x66, 0x9a, 0x22, + ], + xsk: [ + 0x01, 0xff, 0x4c, 0xda, 0x50, 0x01, 0x00, 0x00, 0x80, 0x6a, 0x04, 0x1d, 0xfb, 0x9c, + 0xfe, 0xbe, 0xe9, 0x7c, 0xb1, 0x85, 0x4f, 0xdc, 0x48, 0x1c, 0xc0, 0x4f, 0x02, 0xc9, + 0x57, 0x7a, 0xa6, 0xf1, 0x3b, 0x2c, 0x44, 0x5b, 0x80, 0xa9, 0x66, 0x9a, 0x22, 0x98, + 0xd7, 0x03, 0xfc, 0xb4, 0x05, 0x04, 0xc9, 0x5b, 0x3b, 0x6e, 0xd1, 0x0e, 0xcd, 0x50, + 0x08, 0x2c, 0xff, 0x97, 0xdf, 0xd1, 0xdd, 0x9a, 0xa0, 0x91, 0x3c, 0x78, 0xf9, 0x77, + 0xc9, 0x62, 0xaf, + ], + fp: [ + 0x32, 0xbb, 0xdc, 0x92, 0x1d, 0x06, 0x6f, 0x23, 0x5d, 0xc9, 0x3e, 0x91, 0x3b, 0x8f, + 0xe1, 0xfd, 0x5b, 0x9f, 0x7f, 0x6a, 0x13, 0xd5, 0x6f, 0x18, 0xec, 0x0d, 0x36, 0x20, + 0xd1, 0xf7, 0xb9, 0xa6, + ], + }, + TestVector { + sk: [ + 0x99, 0xaf, 0xd8, 0x89, 0x4b, 0xaa, 0xd5, 0x87, 0x84, 0xd0, 0xec, 0x08, 0xf5, 0x14, + 0x8e, 0xe2, 0xc2, 0xa1, 0x7b, 0x2b, 0x29, 0x4b, 0x08, 0xef, 0x9e, 0x0a, 0x0c, 0xf1, + 0x4b, 0xcc, 0x09, 0x20, + ], + c: [ + 0x6d, 0xa8, 0xb5, 0x7a, 0x36, 0xc7, 0x7a, 0xd6, 0x41, 0x2a, 0x9d, 0xc0, 0x11, 0x5f, + 0x12, 0xac, 0xed, 0x0e, 0xe0, 0x1c, 0x40, 0x2a, 0x0c, 0xf0, 0xa5, 0x07, 0xcb, 0x17, + 0xfc, 0x7b, 0xbd, 0x1d, + ], + xsk: [ + 0x02, 0x32, 0xbb, 0xdc, 0x92, 0x02, 0x00, 0x00, 0x80, 0x6d, 0xa8, 0xb5, 0x7a, 0x36, + 0xc7, 0x7a, 0xd6, 0x41, 0x2a, 0x9d, 0xc0, 0x11, 0x5f, 0x12, 0xac, 0xed, 0x0e, 0xe0, + 0x1c, 0x40, 0x2a, 0x0c, 0xf0, 0xa5, 0x07, 0xcb, 0x17, 0xfc, 0x7b, 0xbd, 0x1d, 0x99, + 0xaf, 0xd8, 0x89, 0x4b, 0xaa, 0xd5, 0x87, 0x84, 0xd0, 0xec, 0x08, 0xf5, 0x14, 0x8e, + 0xe2, 0xc2, 0xa1, 0x7b, 0x2b, 0x29, 0x4b, 0x08, 0xef, 0x9e, 0x0a, 0x0c, 0xf1, 0x4b, + 0xcc, 0x09, 0x20, + ], + fp: [ + 0x36, 0xa5, 0x7c, 0x4f, 0xc5, 0xb8, 0xb4, 0xa3, 0xd6, 0x2f, 0x22, 0xa5, 0x50, 0x08, + 0x78, 0xf3, 0x93, 0x85, 0x6b, 0x7e, 0xcc, 0xe7, 0x71, 0xad, 0x59, 0x7c, 0xa9, 0x64, + 0xb9, 0x86, 0x37, 0xd9, + ], + }, + TestVector { + sk: [ + 0x96, 0x43, 0x9e, 0xa3, 0x48, 0xa4, 0xb2, 0xce, 0x4e, 0xc7, 0xbe, 0xb4, 0x54, 0x3c, + 0x70, 0x27, 0x4c, 0x8f, 0x76, 0x49, 0x5d, 0x60, 0xc5, 0xfa, 0x5f, 0x01, 0x8b, 0x68, + 0xf3, 0xc3, 0x23, 0x67, + ], + c: [ + 0xb1, 0x96, 0xe9, 0xb5, 0x80, 0x9d, 0x76, 0x57, 0x7a, 0x89, 0x44, 0xc3, 0xf8, 0xc8, + 0xa8, 0x3f, 0x93, 0xf0, 0xc8, 0xf5, 0xac, 0xe6, 0xe7, 0xbc, 0x9c, 0xe4, 0x39, 0x6c, + 0x03, 0x4d, 0x93, 0xfe, + ], + xsk: [ + 0x03, 0x36, 0xa5, 0x7c, 0x4f, 0x03, 0x00, 0x00, 0x80, 0xb1, 0x96, 0xe9, 0xb5, 0x80, + 0x9d, 0x76, 0x57, 0x7a, 0x89, 0x44, 0xc3, 0xf8, 0xc8, 0xa8, 0x3f, 0x93, 0xf0, 0xc8, + 0xf5, 0xac, 0xe6, 0xe7, 0xbc, 0x9c, 0xe4, 0x39, 0x6c, 0x03, 0x4d, 0x93, 0xfe, 0x96, + 0x43, 0x9e, 0xa3, 0x48, 0xa4, 0xb2, 0xce, 0x4e, 0xc7, 0xbe, 0xb4, 0x54, 0x3c, 0x70, + 0x27, 0x4c, 0x8f, 0x76, 0x49, 0x5d, 0x60, 0xc5, 0xfa, 0x5f, 0x01, 0x8b, 0x68, 0xf3, + 0xc3, 0x23, 0x67, + ], + fp: [ + 0xbe, 0x1a, 0x1b, 0x66, 0x1d, 0x2c, 0xa3, 0x19, 0x82, 0x2a, 0x32, 0x55, 0x0d, 0x6d, + 0xc4, 0x88, 0xb6, 0x57, 0x1e, 0x0c, 0xd7, 0x81, 0xd5, 0x07, 0x8b, 0x8f, 0x7b, 0xa3, + 0x66, 0xdd, 0xd3, 0x68, + ], + }, +]; diff --git a/src/zip32.rs b/src/zip32.rs index 1ed510926..93b1cf5c8 100644 --- a/src/zip32.rs +++ b/src/zip32.rs @@ -4,7 +4,11 @@ use core::fmt; use blake2b_simd::Params as Blake2bParams; use subtle::{Choice, ConstantTimeEq, CtOption}; -use zip32::ChainCode; +use zcash_spec::VariableLengthSlice; +use zip32::{ + hardened_only::{self, HardenedOnlyKey}, + ChainCode, +}; use crate::{ keys::{FullViewingKey, SpendingKey}, @@ -116,6 +120,15 @@ impl KeyIndex { } } +#[derive(Clone, Copy, Debug)] +struct Orchard; + +impl hardened_only::Context for Orchard { + const MKG_DOMAIN: [u8; 16] = *ZIP32_ORCHARD_PERSONALIZATION; + const CKD_DOMAIN: PrfExpand<([u8; 32], [u8; 4], [u8; 1], VariableLengthSlice)> = + PrfExpand::ORCHARD_ZIP32_CHILD; +} + /// An Orchard extended spending key. /// /// Defined in [ZIP32: Orchard extended keys][orchardextendedkeys]. @@ -126,8 +139,7 @@ pub(crate) struct ExtendedSpendingKey { depth: u8, parent_fvk_tag: FvkTag, child_index: KeyIndex, - chain_code: ChainCode, - sk: SpendingKey, + inner: HardenedOnlyKey, } impl ConstantTimeEq for ExtendedSpendingKey { @@ -135,8 +147,7 @@ impl ConstantTimeEq for ExtendedSpendingKey { self.depth.ct_eq(&rhs.depth) & self.parent_fvk_tag.0.ct_eq(&rhs.parent_fvk_tag.0) & self.child_index.ct_eq(&rhs.child_index) - & self.chain_code.ct_eq(&rhs.chain_code) - & self.sk.ct_eq(&rhs.sk) + & self.inner.ct_eq(&rhs.inner) } } @@ -166,33 +177,19 @@ impl ExtendedSpendingKey { /// /// Panics if the seed is shorter than 32 bytes or longer than 252 bytes. fn master(seed: &[u8]) -> Result { - assert!(seed.len() >= 32 && seed.len() <= 252); - // I := BLAKE2b-512("ZcashIP32Orchard", seed) - let I: [u8; 64] = { - let mut I = Blake2bParams::new() - .hash_length(64) - .personal(ZIP32_ORCHARD_PERSONALIZATION) - .to_state(); - I.update(seed); - I.finalize().as_bytes().try_into().unwrap() - }; - // I_L is used as the master spending key sk_m. - let sk_m = SpendingKey::from_bytes(I[..32].try_into().unwrap()); - if sk_m.is_none().into() { + let m_orchard = HardenedOnlyKey::master(&[seed]); + + let sk = SpendingKey::from_bytes(*m_orchard.parts().0); + if sk.is_none().into() { return Err(Error::InvalidSpendingKey); } - let sk_m = sk_m.unwrap(); - - // I_R is used as the master chain code c_m. - let c_m = ChainCode::new(I[32..].try_into().unwrap()); // For the master extended spending key, depth is 0, parent_fvk_tag is 4 zero bytes, and i is 0. Ok(Self { depth: 0, parent_fvk_tag: FvkTag([0; 4]), child_index: KeyIndex::master(), - chain_code: c_m, - sk: sk_m, + inner: m_orchard, }) } @@ -204,24 +201,12 @@ impl ExtendedSpendingKey { /// /// Discards index if it results in an invalid sk fn derive_child(&self, index: ChildIndex) -> Result { - // I := PRF^Expand(c_par, [0x81] || sk_par || I2LEOSP(i)) - let I: [u8; 64] = PrfExpand::ORCHARD_ZIP32_CHILD.with( - self.chain_code.as_bytes(), - self.sk.to_bytes(), - &index.index().to_le_bytes(), - &[0], - &[], - ); - - // I_L is used as the child spending key sk_i. - let sk_i = SpendingKey::from_bytes(I[..32].try_into().unwrap()); - if sk_i.is_none().into() { + let child_i = self.inner.derive_child(index); + + let sk = SpendingKey::from_bytes(*child_i.parts().0); + if sk.is_none().into() { return Err(Error::InvalidSpendingKey); } - let sk_i = sk_i.unwrap(); - - // I_R is used as the child chain code c_i. - let c_i = ChainCode::new(I[32..].try_into().unwrap()); let fvk: FullViewingKey = self.into(); @@ -229,14 +214,18 @@ impl ExtendedSpendingKey { depth: self.depth + 1, parent_fvk_tag: FvkFingerprint::from(&fvk).tag(), child_index: KeyIndex::child(index), - chain_code: c_i, - sk: sk_i, + inner: child_i, }) } /// Returns sk of this ExtendedSpendingKey. pub fn sk(&self) -> SpendingKey { - self.sk + SpendingKey::from_bytes(*self.inner.parts().0).expect("checked during derivation") + } + + /// Returns the chain code for this ExtendedSpendingKey. + fn chain_code(&self) -> &ChainCode { + self.inner.parts().1 } } @@ -277,4 +266,40 @@ mod tests { .ct_eq(&xsk_5h_7) )); } + + #[test] + fn test_vectors() { + let test_vectors = crate::test_vectors::zip32::TEST_VECTORS; + + let seed = [ + 0, 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, + ]; + + let i1h = ChildIndex::hardened(1); + let i2h = ChildIndex::hardened(2); + let i3h = ChildIndex::hardened(3); + + let m = ExtendedSpendingKey::master(&seed).unwrap(); + let m_1h = m.derive_child(i1h).unwrap(); + let m_1h_2h = ExtendedSpendingKey::from_path(&seed, &[i1h, i2h]).unwrap(); + let m_1h_2h_3h = m_1h_2h.derive_child(i3h).unwrap(); + + let xsks = [m, m_1h, m_1h_2h, m_1h_2h_3h]; + assert_eq!(test_vectors.len(), xsks.len()); + + for (xsk, tv) in xsks.iter().zip(test_vectors.iter()) { + assert_eq!(xsk.sk().to_bytes(), &tv.sk); + assert_eq!(xsk.chain_code().as_bytes(), &tv.c); + + assert_eq!(xsk.depth, tv.xsk[0]); + assert_eq!(&xsk.parent_fvk_tag.0, &tv.xsk[1..5]); + assert_eq!(&xsk.child_index.index().to_le_bytes(), &tv.xsk[5..9]); + assert_eq!(xsk.chain_code().as_bytes(), &tv.xsk[9..9 + 32]); + assert_eq!(xsk.sk().to_bytes(), &tv.xsk[9 + 32..]); + + let fvk: FullViewingKey = (&xsk.sk()).into(); + assert_eq!(FvkFingerprint::from(&fvk).0, tv.fp); + } + } }