Inside Bitcoin

1#!/usr/bin/env python3
2# Copyright (c) 2023 Random "Randy" Lattice and Sean Andersen
3# Distributed under the MIT software license, see the accompanying
4# file COPYING or https://www.opensource.org/licenses/mit-license.php.
5'''
6Generate a C file with ECDSA testvectors from the Wycheproof project.
7'''
8
9import json
10import sys
11
12from wycheproof_utils import to_c_array
13
14filename_input = sys.argv[1]
15
16with open(filename_input) as f:
17    doc = json.load(f)
18
19num_groups = len(doc['testGroups'])
20
21
22num_vectors = 0
23offset_msg_running, offset_pk_running, offset_sig = 0, 0, 0
24out = ""
25messages = ""
26signatures = ""
27public_keys = ""
28cache_msgs = {}
29cache_public_keys = {}
30
31for i in range(num_groups):
32    group = doc['testGroups'][i]
33    num_tests = len(group['tests'])
34    public_key = group['publicKey']
35    for j in range(num_tests):
36        test_vector = group['tests'][j]
37        # // 2 to convert hex to byte length
38        sig_size = len(test_vector['sig']) // 2
39        msg_size = len(test_vector['msg']) // 2
40
41        if test_vector['result'] == "invalid":
42            expected_verify = 0
43        elif test_vector['result'] == "valid":
44            expected_verify = 1
45        else:
46            raise ValueError("invalid result field")
47
48        if num_vectors != 0 and sig_size != 0:
49            signatures += ",\n  "
50
51        new_msg = False
52        msg = to_c_array(test_vector['msg'])
53        msg_offset = offset_msg_running
54        # check for repeated msg
55        if msg not in cache_msgs:
56            if num_vectors != 0 and msg_size != 0:
57                messages += ",\n  "
58            cache_msgs[msg] = offset_msg_running
59            messages += msg
60            new_msg = True
61        else:
62            msg_offset = cache_msgs[msg]
63
64        new_pk = False
65        pk = to_c_array(public_key['uncompressed'])
66        pk_offset = offset_pk_running
67        # check for repeated pk
68        if pk not in cache_public_keys:
69            if num_vectors != 0:
70                public_keys += ",\n  "
71            cache_public_keys[pk] = offset_pk_running
72            public_keys += pk
73            new_pk = True
74        else:
75            pk_offset = cache_public_keys[pk]
76
77        signatures += to_c_array(test_vector['sig'])
78
79        out += "  /" + "* tcId: " + str(test_vector['tcId']) + ". " + test_vector['comment'] + " *" + "/\n"
80        out += f"  {{{pk_offset}, {msg_offset}, {msg_size}, {offset_sig}, {sig_size}, {expected_verify} }},\n"
81        if new_msg:
82            offset_msg_running += msg_size
83        if new_pk:
84            offset_pk_running += 65
85        offset_sig += sig_size
86        num_vectors += 1
87
88struct_definition = """
89typedef struct {
90    size_t pk_offset;
91    size_t msg_offset;
92    size_t msg_len;
93    size_t sig_offset;
94    size_t sig_len;
95    int expected_verify;
96} wycheproof_ecdsa_testvector;
97"""
98
99
100print("/* Note: this file was autogenerated using tests_wycheproof_generate_ecdsa.py. Do not edit. */")
101print(f"#define SECP256K1_ECDSA_WYCHEPROOF_NUMBER_TESTVECTORS ({num_vectors})")
102
103print(struct_definition)
104
105print("static const unsigned char wycheproof_ecdsa_messages[]    = { " + messages + "};\n")
106print("static const unsigned char wycheproof_ecdsa_public_keys[] = { " + public_keys + "};\n")
107print("static const unsigned char wycheproof_ecdsa_signatures[]  = { " + signatures + "};\n")
108
109print("static const wycheproof_ecdsa_testvector testvectors[SECP256K1_ECDSA_WYCHEPROOF_NUMBER_TESTVECTORS] = {")
110print(out)
111print("};")
112