feat: use recoverable signature to reduce tx size

.gitignore

@@ -54,3 +54,6 @@ dkms.conf
 build/
 c/flatbuffers_common_reader.h
 c/protocol_reader.h
+
+tests/target
+tests/tmp

.travis.yml

@@ -0,0 +1,26 @@
+language: rust
+rust: 1.34.2
+dist: xenial
+sudo: true
+cache:
+  cargo: true
+  timeout: 1024
+
+git:
+  depth: 2
+
+env:
+  global:
+    - RUST_BACKTRACE=full
+
+before_install:
+  - cargo sweep --version || cargo install --git https://github.com/holmgr/cargo-sweep --rev 4770deda37a2203c783e301b8c0c895964e8971e
+  - cargo sweep -s
+
+script: make ci
+
+before_cache:
+  - rm -rf ./target/release
+  - rm -rf ./target/debug/incremental/
+  - cargo sweep -f
+

Makefile

@@ -14,7 +14,7 @@ build/secp256k1_blake160_sighash_all: c/secp256k1_blake160_sighash_all.c c/proto
 $(SECP256K1_LIB):
 	cd deps/secp256k1 && \
 		./autogen.sh && \
-		CC=$(CC) LD=$(LD) ./configure --with-bignum=no --enable-ecmult-static-precomputation --enable-endomorphism --host=$(TARGET) && \
+		CC=$(CC) LD=$(LD) ./configure --with-bignum=no --enable-ecmult-static-precomputation --enable-endomorphism --enable-module-recovery --host=$(TARGET) && \
 		make libsecp256k1.la
 
 c/protocol_reader.h: c/protocol.fbs $(FLATCC)
@@ -24,6 +24,12 @@ c/protocol_reader.h: c/protocol.fbs $(FLATCC)
 $(FLATCC):
 	cd deps/flatcc && scripts/initbuild.sh make && scripts/build.sh
 
+ci:
+	docker run --rm -v `pwd`:/code xxuejie/riscv-gnu-toolchain-rv64imac:xenial-20190606 bash -c "cd /code && make"
+	mkdir -p tests/tmp
+	cp build/secp256k1_blake160_sighash_all tests/tmp/
+	cd tests && cargo test
+
 clean:
 	rm -rf build/secp256k1_blake160_sighash_all
 	cd deps/flatcc && scripts/cleanall.sh

README.md

@@ -1,2 +1,4 @@
 # ckb-contracts
+[![Build Status](https://travis-ci.com/nervosnetwork/ckb-system-scripts.svg?branch=master)](https://travis-ci.com/nervosnetwork/ckb-system-scripts)
+
 CKB's official smart contracts. Those contracts will be included in system cells in genesis blocks

c/secp256k1_blake160_sighash_all.c

@@ -11,16 +11,17 @@
 #define ERROR_SYSCALL -4
 #define ERROR_SECP_ABORT -5
 #define ERROR_SECP_INITIALIZE -6
-#define ERROR_SECP_PARSE_PUBKEY -7
+#define ERROR_SECP_RECOVER_PUBKEY -7
 #define ERROR_SECP_PARSE_SIGNATURE -8
-#define ERROR_SECP_VERIFICATION -9
+#define ERROR_SECP_SERIALIZE_PUBKEY -9
 #define ERROR_BUFFER_NOT_ENOUGH -10
 #define ERROR_ENCODING -11
 
 #define BLAKE2B_BLOCK_SIZE 32
 #define BLAKE160_SIZE 20
 #define PUBKEY_SIZE 33
 #define TEMP_SIZE 1024
+#define RECID_INDEX 64
 /* 32 KB */
 #define WITNESS_SIZE 32768
 
@@ -71,13 +72,13 @@ static int extract_bytes(ns(Bytes_table_t) bytes, unsigned char *buffer, volatil
  * pubkey in lock script.
  *
  * Witness:
- * 2. pubkey, real pubkey used to identify token owner
- * 3. signature, signature used to present ownership
- * 4. signature size, in little endian 64 bit unsigned integer
+ * 1. signature, signature used to present ownership
+ * 2. signature size, in little endian 64 bit unsigned integer
  */
 int main(int argc, char* argv[])
 {
   int ret;
+  int recid;
   size_t index = 0;
   uint64_t signature_size = 0;
   volatile uint64_t len = 0;
@@ -131,52 +132,28 @@ int main(int argc, char* argv[])
       return ERROR_ENCODING;
     }
     args = ns(Witness_data(witness_table));
-    if (ns(Bytes_vec_len(args)) < 2) {
+    if (ns(Bytes_vec_len(args)) < 1) {
       return ERROR_WRONG_NUMBER_OF_ARGUMENTS;
     }
 
-    /* Check pubkey hash */
-    len = TEMP_SIZE;
-    ret = extract_bytes(ns(Bytes_vec_at(args, 0)), temp, &len);
-    if (ret != CKB_SUCCESS) {
-      return ERROR_ENCODING;
-    }
-    blake2b_state blake2b_ctx;
-    blake2b_init(&blake2b_ctx, BLAKE2B_BLOCK_SIZE);
-    blake2b_update(&blake2b_ctx, temp, len);
-    blake2b_final(&blake2b_ctx, temp, BLAKE2B_BLOCK_SIZE);
-
-    if (memcmp(argv[1], temp, BLAKE160_SIZE) != 0) {
-      return ERROR_PUBKEY_BLAKE160_HASH;
-    }
-
-    /* load pubkey */
-    len = TEMP_SIZE;
-    ret = extract_bytes(ns(Bytes_vec_at(args, 0)), temp, &len);
-    if (ret != CKB_SUCCESS) {
-      return ERROR_ENCODING;
-    }
-
-    secp256k1_pubkey pubkey;
-    if (secp256k1_ec_pubkey_parse(&context, &pubkey, temp, len) == 0) {
-      return ERROR_SECP_PARSE_PUBKEY;
-    }
-
     /* Load signature */
     len = TEMP_SIZE;
-    ret = extract_bytes(ns(Bytes_vec_at(args, 1)), temp, &len);
+    ret = extract_bytes(ns(Bytes_vec_at(args, 0)), temp, &len);
     if (ret != CKB_SUCCESS) {
       return ERROR_ENCODING;
     }
 
-    secp256k1_ecdsa_signature signature;
-    if (secp256k1_ecdsa_signature_parse_der(&context, &signature, temp, len) == 0) {
+    /* The 65th byte is recid according to contract spec.*/
+    recid = temp[RECID_INDEX];
+    /* Recover pubkey */
+    secp256k1_ecdsa_recoverable_signature signature;
+    if (secp256k1_ecdsa_recoverable_signature_parse_compact(&context, &signature, temp, recid) == 0) {
       return ERROR_SECP_PARSE_SIGNATURE;
     }
-
+    blake2b_state blake2b_ctx;
     blake2b_init(&blake2b_ctx, BLAKE2B_BLOCK_SIZE);
     blake2b_update(&blake2b_ctx, tx_hash, BLAKE2B_BLOCK_SIZE);
-    for (size_t i = 2; i < ns(Bytes_vec_len(args)); i++) {
+    for (size_t i = 1; i < ns(Bytes_vec_len(args)); i++) {
       len = TEMP_SIZE;
       ret = extract_bytes(ns(Bytes_vec_at(args, i)), temp, &len);
       if (ret != CKB_SUCCESS) {
@@ -186,8 +163,25 @@ int main(int argc, char* argv[])
     }
     blake2b_final(&blake2b_ctx, temp, BLAKE2B_BLOCK_SIZE);
 
-    if (secp256k1_ecdsa_verify(&context, &signature, temp, &pubkey) != 1) {
-      return ERROR_SECP_VERIFICATION;
+    secp256k1_pubkey pubkey;
+
+    if (secp256k1_ecdsa_recover(&context, &pubkey, &signature, temp) != 1) {
+      return ERROR_SECP_RECOVER_PUBKEY;
+    }
+
+    /* Check pubkey hash */
+    size_t pubkey_size = PUBKEY_SIZE;
+    if (secp256k1_ec_pubkey_serialize(&context, temp, &pubkey_size, &pubkey, SECP256K1_EC_COMPRESSED) != 1 ) {
+      return ERROR_SECP_SERIALIZE_PUBKEY;
+    }
+
+    len = PUBKEY_SIZE;
+    blake2b_init(&blake2b_ctx, BLAKE2B_BLOCK_SIZE);
+    blake2b_update(&blake2b_ctx, temp, len);
+    blake2b_final(&blake2b_ctx, temp, BLAKE2B_BLOCK_SIZE);
+
+    if (memcmp(argv[1], temp, BLAKE160_SIZE) != 0) {
+      return ERROR_PUBKEY_BLAKE160_HASH;
     }
 
     index += 1;