This repository has been archived by the owner on Jul 12, 2023. It is now read-only.
-
Notifications
You must be signed in to change notification settings - Fork 310
/
generate.go
192 lines (174 loc) · 4.95 KB
/
generate.go
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
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
// Copyright 2020 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Package util is a CLI tool for generating test exposure key data.
package util
import (
"crypto/rand"
"encoding/base64"
"log"
"math/big"
"time"
v1 "github.com/google/exposure-notifications-server/pkg/api/v1"
"github.com/google/exposure-notifications-server/pkg/base64util"
)
const (
// the length of a diagnosis key, always 16 bytes
dkLen = 16
maxIntervalCount = 144
)
// RandomIntervalCount produces a random interval.
func RandomIntervalCount() (int32, error) {
n, err := rand.Int(rand.Reader, big.NewInt(maxIntervalCount))
if err != nil {
return 0, err
}
return int32(n.Int64() + 1), nil // valid values start at 1
}
// RandomInt produces a random integer up to but not including maxValue.
func RandomInt(maxValue int) (int, error) {
n, err := rand.Int(rand.Reader, big.NewInt(int64(maxValue)))
if err != nil {
return 0, err
}
return int(n.Int64()), nil
}
// RandomIntWithMin is inclusive, [min:max].
func RandomIntWithMin(min, max int) (int, error) {
n, err := rand.Int(rand.Reader, big.NewInt(int64(max-min+1)))
if err != nil {
return 0, err
}
return int(n.Int64()) + min, nil
}
func RandomRevisedReportType() (string, error) {
n, err := RandomInt(2)
if err != nil {
return "", err
}
switch n {
case 0:
return v1.ReportTypeConfirmed, nil
case 1:
return v1.ReportTypeNegative, nil
}
return v1.ReportTypeConfirmed, nil
}
func RandomReportType() (string, error) {
n, err := RandomInt(3)
if err != nil {
return "", err
}
switch n {
case 0:
return v1.ReportTypeConfirmed, nil
case 1:
return v1.ReportTypeClinical, nil
case 2:
return v1.ReportTypeNegative, nil
}
return v1.ReportTypeConfirmed, nil
}
// RandomTransmissionRisk produces a random transmission risk score.
func RandomTransmissionRisk() (int, error) {
n, err := RandomInt(v1.MaxTransmissionRisk)
return n + 1, err
}
// RandomArrValue chooses a random element from the array.
func RandomArrValue(arr []string) (string, error) {
n, err := RandomInt(len(arr))
if err != nil {
return "", err
}
return arr[n], nil
}
// GenerateExposureKeys creates the given number of exposure keys.
func GenerateExposureKeys(numKeys, tr int, randomInterval bool) []v1.ExposureKey {
// When publishing multiple keys - they'll be on different days.
var err error
intervalCount := int32(144)
if randomInterval {
intervalCount, err = RandomIntervalCount()
if err != nil {
log.Fatalf("problem with random interval: %v", err)
}
}
// Keys will normally align to UTC day boundries.
utcDay := time.Now().UTC().Truncate(24 * time.Hour)
intervalNumber := int32(utcDay.Unix()/600) - intervalCount
exposureKeys := make([]v1.ExposureKey, numKeys)
for i := 0; i < numKeys; i++ {
transmissionRisk := tr
if transmissionRisk < 0 {
transmissionRisk, err = RandomTransmissionRisk()
if err != nil {
log.Fatalf("problem with transmission risk: %v", err)
}
}
exposureKeys[i], err = RandomExposureKey(intervalNumber, intervalCount, transmissionRisk)
if err != nil {
log.Fatalf("problem creating random exposure key: %v", err)
}
// Adjust interval math for next key.
if randomInterval {
intervalCount, err = RandomIntervalCount()
if err != nil {
log.Fatalf("problem with random interval: %v", err)
}
}
intervalNumber -= intervalCount
}
return exposureKeys
}
// RandomExposureKey creates a random exposure key.
func RandomExposureKey(intervalNumber int32, intervalCount int32, transmissionRisk int) (v1.ExposureKey, error) {
key, err := GenerateKey()
if err != nil {
return v1.ExposureKey{}, err
}
return v1.ExposureKey{
Key: key,
IntervalNumber: int32(intervalNumber),
IntervalCount: intervalCount,
TransmissionRisk: transmissionRisk,
}, nil
}
// RandomBytes generates a random byte sequence.
func RandomBytes(arrLen int) ([]byte, error) {
padding := make([]byte, arrLen)
_, err := rand.Read(padding)
if err != nil {
return nil, err
}
return padding, nil
}
// GenerateKey generates a key.
func GenerateKey() (string, error) {
b, err := RandomBytes(dkLen)
if err != nil {
return "", err
}
return ToBase64(b), nil
}
// ToBase64 encodes bytes array to base64.
func ToBase64(key []byte) string {
return base64.StdEncoding.EncodeToString(key)
}
// DecodeKey decodes base64 string to []byte.
func DecodeKey(b64key string) []byte {
k, err := base64util.DecodeString(b64key)
if err != nil {
log.Fatalf("unable to decode key: %v", err)
}
return k
}