Compute TxId for Transaction

Cargo.lock

@@ -72,6 +72,17 @@ dependencies = [
  "constant_time_eq 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "block-buffer"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "block-padding 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "byte-tools 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "byteorder 1.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "generic-array 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "block-cipher-trait"
 version = "0.5.3"
@@ -80,11 +91,24 @@ dependencies = [
  "generic-array 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "block-padding"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "byte-tools 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "byte-tools"
 version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "byte-tools"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "byteorder"
 version = "1.2.2"
@@ -108,6 +132,19 @@ dependencies = [
  "generic-array 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "digest"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "generic-array 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "fake-simd"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "ff"
 version = "0.4.0"
@@ -182,6 +219,14 @@ dependencies = [
  "typenum 1.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "generic-array"
+version = "0.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "typenum 1.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "group"
 version = "0.1.0"
@@ -280,6 +325,11 @@ name = "opaque-debug"
 version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "opaque-debug"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "pairing"
 version = "0.14.2"
@@ -376,6 +426,17 @@ dependencies = [
  "rust-crypto 0.2.36 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "sha2"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "block-buffer 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "digest 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "fake-simd 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "opaque-debug 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "stream-cipher"
 version = "0.1.1"
@@ -445,6 +506,7 @@ dependencies = [
  "pairing 0.14.2",
  "rand 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sapling-crypto 0.0.1",
+ "sha2 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -486,18 +548,24 @@ dependencies = [
 "checksum bit-vec 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)" = "02b4ff8b16e6076c3e14220b39fbc1fabb6737522281a388998046859400895f"
 "checksum bitflags 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "b3c30d3802dfb7281680d6285f2ccdaa8c2d8fee41f93805dba5c4cf50dc23cf"
 "checksum blake2-rfc 0.2.18 (git+https://github.com/gtank/blake2-rfc?rev=7a5b5fc99ae483a0043db7547fb79a6fa44b88a9)" = "<none>"
+"checksum block-buffer 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "49665c62e0e700857531fa5d3763e91b539ff1abeebd56808d378b495870d60d"
 "checksum block-cipher-trait 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)" = "370424437b9459f3dfd68428ed9376ddfe03d8b70ede29cc533b3557df186ab4"
+"checksum block-padding 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "4fc4358306e344bf9775d0197fd00d2603e5afb0771bb353538630f022068ea3"
 "checksum byte-tools 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "560c32574a12a89ecd91f5e742165893f86e3ab98d21f8ea548658eb9eef5f40"
+"checksum byte-tools 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "980479e6fde23246dfb54d47580d66b4e99202e7579c5eaa9fe10ecb5ebd2182"
 "checksum byteorder 1.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "73b5bdfe7ee3ad0b99c9801d58807a9dbc9e09196365b0203853b99889ab3c87"
 "checksum constant_time_eq 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "8ff012e225ce166d4422e0e78419d901719760f62ae2b7969ca6b564d1b54a9e"
 "checksum crossbeam 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)" = "24ce9782d4d5c53674646a6a4c1863a21a8fc0cb649b3c94dfc16e45071dea19"
 "checksum digest 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)" = "00a49051fef47a72c9623101b19bd71924a45cca838826caae3eaa4d00772603"
+"checksum digest 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "05f47366984d3ad862010e22c7ce81a7dbcaebbdfb37241a620f8b6596ee135c"
+"checksum fake-simd 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "e88a8acf291dafb59c2d96e8f59828f3838bb1a70398823ade51a84de6a6deed"
 "checksum fpe 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ce3371c82bfbd984f624cab093f55e7336f5a6e589f8518e1258f54f011b89ad"
 "checksum fuchsia-zircon 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "2e9763c69ebaae630ba35f74888db465e49e259ba1bc0eda7d06f4a067615d82"
 "checksum fuchsia-zircon-sys 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "3dcaa9ae7725d12cdb85b3ad99a434db70b468c09ded17e012d86b5c1010f7a7"
 "checksum futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)" = "1a70b146671de62ec8c8ed572219ca5d594d9b06c0b364d5e67b722fc559b48c"
 "checksum futures-cpupool 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)" = "ab90cde24b3319636588d0c35fe03b1333857621051837ed769faefb4c2162e4"
 "checksum gcc 0.3.54 (registry+https://github.com/rust-lang/crates.io-index)" = "5e33ec290da0d127825013597dbdfc28bee4964690c7ce1166cbc2a7bd08b1bb"
+"checksum generic-array 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3c0f28c2f5bfb5960175af447a2da7c18900693738343dc896ffbcabd9839592"
 "checksum generic-array 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ef25c5683767570c2bbd7deba372926a55eaae9982d7726ee2a1050239d45b9d"
 "checksum hex 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)" = "805026a5d0141ffc30abb3be3173848ad46a1b1664fe632428479619a3644d77"
 "checksum hex-literal 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "4da5f0e01bd8a71a224a4eedecaacfcabda388dbb7a80faf04d3514287572d95"
@@ -510,6 +578,7 @@ dependencies = [
 "checksum num-traits 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)" = "630de1ef5cc79d0cdd78b7e33b81f083cbfe90de0f4b2b2f07f905867c70e9fe"
 "checksum num_cpus 1.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "c51a3322e4bca9d212ad9a158a02abc6934d005490c054a2778df73a70aa0a30"
 "checksum opaque-debug 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "d620c9c26834b34f039489ac0dfdb12c7ac15ccaf818350a64c9b5334a452ad7"
+"checksum opaque-debug 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "93f5bb2e8e8dec81642920ccff6b61f1eb94fa3020c5a325c9851ff604152409"
 "checksum proc-macro-hack 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3ba8d4f9257b85eb6cdf13f055cea3190520aab1409ca2ab43493ea4820c25f0"
 "checksum proc-macro-hack-impl 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d5cb6f960ad471404618e9817c0e5d10b1ae74cfdf01fab89ea0641fe7fb2892"
 "checksum proc-macro2 0.4.14 (registry+https://github.com/rust-lang/crates.io-index)" = "b331c6ad3411474cd55540398dc7ad89fc41488e64ec71fdecc9c9b86de96fb0"
@@ -519,6 +588,7 @@ dependencies = [
 "checksum redox_syscall 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)" = "c214e91d3ecf43e9a4e41e578973adeb14b474f2bee858742d127af75a0112b1"
 "checksum rust-crypto 0.2.36 (registry+https://github.com/rust-lang/crates.io-index)" = "f76d05d3993fd5f4af9434e8e436db163a12a9d40e1a58a726f27a01dfd12a2a"
 "checksum rustc-serialize 0.3.24 (registry+https://github.com/rust-lang/crates.io-index)" = "dcf128d1287d2ea9d80910b5f1120d0b8eede3fbf1abe91c40d39ea7d51e6fda"
+"checksum sha2 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7b4d8bfd0e469f417657573d8451fb33d16cfe0989359b93baf3a1ffc639543d"
 "checksum stream-cipher 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "30dc6118470d69ce0fdcf7e6f95e95853f7f4f72f80d835d4519577c323814ab"
 "checksum syn 0.14.9 (registry+https://github.com/rust-lang/crates.io-index)" = "261ae9ecaa397c42b960649561949d69311f08eeaea86a65696e6e46517cf741"
 "checksum time 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)" = "d825be0eb33fda1a7e68012d51e9c7f451dc1a69391e7fdc197060bb8c56667b"

zcash_primitives/Cargo.toml

@@ -13,6 +13,7 @@ lazy_static = "1"
 pairing = { path = "../pairing" }
 rand = "0.4"
 sapling-crypto = { path = "../sapling-crypto" }
+sha2 = "0.8"
 
 [dependencies.blake2-rfc]
 git = "https://github.com/gtank/blake2-rfc"

zcash_primitives/src/lib.rs

@@ -8,6 +8,7 @@ extern crate hex;
 extern crate pairing;
 extern crate rand;
 extern crate sapling_crypto;
+extern crate sha2;
 
 use sapling_crypto::jubjub::JubjubBls12;
 

zcash_primitives/src/transaction/mod.rs

@@ -1,6 +1,7 @@
 use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
 use hex;
 use sapling_crypto::redjubjub::Signature;
+use sha2::{Digest, Sha256};
 use std::fmt;
 use std::io::{self, Read, Write};
 use std::ops::Deref;
@@ -35,7 +36,7 @@ impl fmt::Display for TxId {
 
 /// A Zcash transaction.
 #[derive(Debug)]
-pub struct Transaction(TransactionData);
+pub struct Transaction(TransactionData, TxId);
 
 impl Deref for Transaction {
     type Target = TransactionData;
@@ -125,12 +126,26 @@ impl TransactionData {
         header
     }
 
-    pub fn freeze(self) -> Transaction {
-        Transaction(self)
+    pub fn freeze(self) -> io::Result<Transaction> {
+        Transaction::from_data(self)
     }
 }
 
 impl Transaction {
+    fn from_data(data: TransactionData) -> io::Result<Self> {
+        let mut tx = Transaction(data, TxId([0; 32]));
+        let mut raw = vec![];
+        tx.write(&mut raw)?;
+        (tx.1)
+            .0
+            .copy_from_slice(&Sha256::digest(&Sha256::digest(&raw)));
+        Ok(tx)
+    }
+
+    pub fn txid(&self) -> TxId {
+        self.1
+    }
+
     pub fn read<R: Read>(mut reader: R) -> io::Result<Self> {
         let header = reader.read_u32::<LittleEndian>()?;
         let overwintered = (header >> 31) == 1;
@@ -195,7 +210,7 @@ impl Transaction {
                 false => None,
             };
 
-        Ok(Transaction(TransactionData {
+        Transaction::from_data(TransactionData {
             overwintered,
             version,
             version_group_id,
@@ -210,7 +225,7 @@ impl Transaction {
             joinsplit_pubkey,
             joinsplit_sig,
             binding_sig,
-        }))
+        })
     }
 
     pub fn write<W: Write>(&self, mut writer: W) -> io::Result<()> {

zcash_primitives/src/transaction/tests.rs

@@ -159,51 +159,33 @@ fn tx_read_write() {
 #[test]
 fn tx_write_rejects_unexpected_joinsplit_pubkey() {
     // Succeeds without a JoinSplit pubkey
-    {
-        let tx = TransactionData::new().freeze();
-        let mut encoded = Vec::new();
-        assert!(tx.write(&mut encoded).is_ok());
-    }
+    assert!(TransactionData::new().freeze().is_ok());
 
     // Fails with an unexpected JoinSplit pubkey
     {
         let mut tx = TransactionData::new();
         tx.joinsplit_pubkey = Some([0; 32]);
-        let tx = tx.freeze();
-
-        let mut encoded = Vec::new();
-        assert!(tx.write(&mut encoded).is_err());
+        assert!(tx.freeze().is_err());
     }
 }
 
 #[test]
 fn tx_write_rejects_unexpected_joinsplit_sig() {
     // Succeeds without a JoinSplit signature
-    {
-        let tx = TransactionData::new().freeze();
-        let mut encoded = Vec::new();
-        assert!(tx.write(&mut encoded).is_ok());
-    }
+    assert!(TransactionData::new().freeze().is_ok());
 
     // Fails with an unexpected JoinSplit signature
     {
         let mut tx = TransactionData::new();
         tx.joinsplit_sig = Some([0; 64]);
-        let tx = tx.freeze();
-
-        let mut encoded = Vec::new();
-        assert!(tx.write(&mut encoded).is_err());
+        assert!(tx.freeze().is_err());
     }
 }
 
 #[test]
 fn tx_write_rejects_unexpected_binding_sig() {
     // Succeeds without a binding signature
-    {
-        let tx = TransactionData::new().freeze();
-        let mut encoded = Vec::new();
-        assert!(tx.write(&mut encoded).is_ok());
-    }
+    assert!(TransactionData::new().freeze().is_ok());
 
     // Fails with an unexpected binding signature
     {
@@ -218,10 +200,7 @@ fn tx_write_rejects_unexpected_binding_sig() {
 
         let mut tx = TransactionData::new();
         tx.binding_sig = Some(sig);
-        let tx = tx.freeze();
-
-        let mut encoded = Vec::new();
-        assert!(tx.write(&mut encoded).is_err());
+        assert!(tx.freeze().is_err());
     }
 }