ZIP 32 APIs

Cargo.toml

@@ -29,6 +29,10 @@ rev = "7a5b5fc99ae483a0043db7547fb79a6fa44b88a9"
 git = "https://github.com/zcash-hackworks/sapling-crypto"
 rev = "21084bde2019c04bd34208e63c3560fe2c02fb0e"
 
+[dependencies.zip32]
+git = "https://github.com/zcash-hackworks/zip32"
+rev = "176470ef41583b5bd0bd749bd1b61d417aa8ec79"
+
 [profile.release]
 lto = true
 panic = 'abort'

include/librustzcash.h

@@ -270,6 +270,35 @@ extern "C" {
         uint64_t vpub_old,
         uint64_t vpub_new
     );
+
+    /// Derive the master ExtendedSpendingKey from a seed.
+    void librustzcash_zip32_xsk_master(
+        const unsigned char *seed,
+        size_t seedlen,
+        unsigned char *xsk_master
+    );
+
+    /// Derive a child ExtendedSpendingKey from a parent.
+    void librustzcash_zip32_xsk_derive(
+        const unsigned char *xsk_parent,
+        uint32_t i,
+        unsigned char *xsk_i
+    );
+
+    /// Derive a child ExtendedFullViewingKey from a parent.
+    bool librustzcash_zip32_xfvk_derive(
+        const unsigned char *xfvk_parent,
+        uint32_t i,
+        unsigned char *xfvk_i
+    );
+
+    /// Derive a PaymentAddress from an ExtendedFullViewingKey.
+    bool librustzcash_zip32_xfvk_address(
+        const unsigned char *xfvk,
+        const unsigned char *j,
+        unsigned char *j_ret,
+        unsigned char *addr_ret
+    );
 }
 
 #endif // LIBRUSTZCASH_INCLUDE_H_

src/rustzcash.rs

@@ -5,6 +5,7 @@ extern crate libc;
 extern crate pairing;
 extern crate rand;
 extern crate sapling_crypto;
+extern crate zip32;
 
 mod hashreader;
 
@@ -1567,3 +1568,86 @@ pub extern "system" fn librustzcash_sapling_proving_ctx_init() -> *mut SaplingPr
 pub extern "system" fn librustzcash_sapling_proving_ctx_free(ctx: *mut SaplingProvingContext) {
     drop(unsafe { Box::from_raw(ctx) });
 }
+
+#[no_mangle]
+pub extern "system" fn librustzcash_zip32_xsk_master(
+    seed: *const c_uchar,
+    seedlen: size_t,
+    xsk_master: *mut [c_uchar; 169],
+) {
+    let seed = unsafe { std::slice::from_raw_parts(seed, seedlen) };
+
+    let xsk = zip32::ExtendedSpendingKey::master(seed);
+
+    xsk.write(&mut (unsafe { &mut *xsk_master })[..])
+        .expect("should be able to serialize an ExtendedSpendingKey");
+}
+
+#[no_mangle]
+pub extern "system" fn librustzcash_zip32_xsk_derive(
+    xsk_parent: *const [c_uchar; 169],
+    i: uint32_t,
+    xsk_i: *mut [c_uchar; 169],
+) {
+    let xsk_parent = zip32::ExtendedSpendingKey::read(&unsafe { *xsk_parent }[..])
+        .expect("valid ExtendedSpendingKey");
+    let i = zip32::ChildIndex::from_index(i);
+
+    let xsk = xsk_parent.derive_child(i);
+
+    xsk.write(&mut (unsafe { &mut *xsk_i })[..])
+        .expect("should be able to serialize an ExtendedSpendingKey");
+}
+
+#[no_mangle]
+pub extern "system" fn librustzcash_zip32_xfvk_derive(
+    xfvk_parent: *const [c_uchar; 169],
+    i: uint32_t,
+    xfvk_i: *mut [c_uchar; 169],
+) -> bool {
+    let xfvk_parent = zip32::ExtendedFullViewingKey::read(&unsafe { *xfvk_parent }[..])
+        .expect("valid ExtendedFullViewingKey");
+    let i = zip32::ChildIndex::from_index(i);
+
+    let xfvk = match xfvk_parent.derive_child(i) {
+        Ok(xfvk) => xfvk,
+        Err(_) => return false,
+    };
+
+    xfvk.write(&mut (unsafe { &mut *xfvk_i })[..])
+        .expect("should be able to serialize an ExtendedFullViewingKey");
+
+    true
+}
+
+#[no_mangle]
+pub extern "system" fn librustzcash_zip32_xfvk_address(
+    xfvk: *const [c_uchar; 169],
+    j: *const [c_uchar; 11],
+    j_ret: *mut [c_uchar; 11],
+    addr_ret: *mut [c_uchar; 43],
+) -> bool {
+    let xfvk = zip32::ExtendedFullViewingKey::read(&unsafe { *xfvk }[..])
+        .expect("valid ExtendedFullViewingKey");
+    let j = zip32::DiversifierIndex(unsafe { *j });
+
+    let addr = match xfvk.address(j) {
+        Ok(addr) => addr,
+        Err(_) => return false,
+    };
+
+    let j_ret = unsafe { &mut *j_ret };
+    let addr_ret = unsafe { &mut *addr_ret };
+
+    j_ret.copy_from_slice(&(addr.0).0);
+    addr_ret
+        .get_mut(..11)
+        .unwrap()
+        .copy_from_slice(&addr.1.diversifier.0);
+    addr.1
+        .pk_d
+        .write(addr_ret.get_mut(11..).unwrap())
+        .expect("should be able to serialize a PaymentAddress");
+
+    true
+}