Maxim Integrated / Mbed OS MAXREFDES155#

DeepCover Embedded Security in IoT: Public-key Secured Data Paths

Dependencies:   MaximInterface

The MAXREFDES155# is an internet-of-things (IoT) embedded-security reference design, built to authenticate and control a sensing node using elliptic-curve-based public-key cryptography with control and notification from a web server.

The hardware includes an ARM® mbed™ shield and attached sensor endpoint. The shield contains a DS2476 DeepCover® ECDSA/SHA-2 coprocessor, Wifi communication, LCD push-button controls, and status LEDs. The sensor endpoint is attached to the shield using a 300mm cable and contains a DS28C36 DeepCover ECDSA/SHA-2 authenticator, IR-thermal sensor, and aiming laser for the IR sensor. The MAXREFDES155# is equipped with a standard Arduino® form-factor shield connector for immediate testing using an mbed board such as the MAX32600MBED#. The combination of these two devices represent an IoT device. Communication to the web server is accomplished with the shield Wifi circuitry. Communication from the shield to the attached sensor module is accomplished over I2C . The sensor module represents an IoT endpoint that generates small data with a requirement for message authenticity/integrity and secure on/off operational control.

The design is hierarchical with each mbed platform and shield communicating data from the sensor node to a web server that maintains a centralized log and dispatches notifications as necessary. The simplicity of this design enables rapid integration into any star-topology IoT network to provide security with the low overhead and cost provided by the ECDSA-P256 asymmetric-key and SHA-256 symmetric-key algorithms.

More information about the MAXREFDES155# is available on the Maxim Integrated website.

SensorNode.cpp@15:75404fab3615, 2018-01-19 (annotated)

Committer:
IanBenzMaxim
Date:
Fri Jan 19 10:28:27 2018 -0600
Revision:
15:75404fab3615
Parent:
14:dc839a69379b 
Updated MaximInterface revision.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
IanBenzMaxim 0:33d4e66780c0 1 /*******************************************************************************
IanBenzMaxim 0:33d4e66780c0 2 * Copyright (C) 2017 Maxim Integrated Products, Inc., All Rights Reserved.
IanBenzMaxim 0:33d4e66780c0 3 *
IanBenzMaxim 0:33d4e66780c0 4 * Permission is hereby granted, free of charge, to any person obtaining a
IanBenzMaxim 0:33d4e66780c0 5 * copy of this software and associated documentation files (the "Software"),
IanBenzMaxim 0:33d4e66780c0 6 * to deal in the Software without restriction, including without limitation
IanBenzMaxim 0:33d4e66780c0 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
IanBenzMaxim 0:33d4e66780c0 8 * and/or sell copies of the Software, and to permit persons to whom the
IanBenzMaxim 0:33d4e66780c0 9 * Software is furnished to do so, subject to the following conditions:
IanBenzMaxim 0:33d4e66780c0 10 *
IanBenzMaxim 0:33d4e66780c0 11 * The above copyright notice and this permission notice shall be included
IanBenzMaxim 0:33d4e66780c0 12 * in all copies or substantial portions of the Software.
IanBenzMaxim 0:33d4e66780c0 13 *
IanBenzMaxim 0:33d4e66780c0 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
IanBenzMaxim 0:33d4e66780c0 15 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
IanBenzMaxim 0:33d4e66780c0 16 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IanBenzMaxim 0:33d4e66780c0 17 * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
IanBenzMaxim 0:33d4e66780c0 18 * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
IanBenzMaxim 0:33d4e66780c0 19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
IanBenzMaxim 0:33d4e66780c0 20 * OTHER DEALINGS IN THE SOFTWARE.
IanBenzMaxim 0:33d4e66780c0 21 *
IanBenzMaxim 0:33d4e66780c0 22 * Except as contained in this notice, the name of Maxim Integrated
IanBenzMaxim 0:33d4e66780c0 23 * Products, Inc. shall not be used except as stated in the Maxim Integrated
IanBenzMaxim 0:33d4e66780c0 24 * Products, Inc. Branding Policy.
IanBenzMaxim 0:33d4e66780c0 25 *
IanBenzMaxim 0:33d4e66780c0 26 * The mere transfer of this software does not imply any licenses
IanBenzMaxim 0:33d4e66780c0 27 * of trade secrets, proprietary technology, copyrights, patents,
IanBenzMaxim 0:33d4e66780c0 28 * trademarks, maskwork rights, or any other form of intellectual
IanBenzMaxim 0:33d4e66780c0 29 * property whatsoever. Maxim Integrated Products, Inc. retains all
IanBenzMaxim 0:33d4e66780c0 30 * ownership rights.
IanBenzMaxim 0:33d4e66780c0 31 *******************************************************************************/
IanBenzMaxim 0:33d4e66780c0 32
IanBenzMaxim 0:33d4e66780c0 33 #include <string>
IanBenzMaxim 0:33d4e66780c0 34 #include <I2C.h>
IanBenzMaxim 13:6a6225690c2e 35 #include <MaximInterface/Utilities/RomId.hpp>
IanBenzMaxim 13:6a6225690c2e 36 #include <MaximInterface/Utilities/ManId.hpp>
IanBenzMaxim 13:6a6225690c2e 37 #include <MaximInterface/Utilities/HexConversions.hpp>
IanBenzMaxim 13:6a6225690c2e 38 #include <MaximInterface/Platforms/mbed/Sleep.hpp>
IanBenzMaxim 0:33d4e66780c0 39 #include "Factory.hpp"
IanBenzMaxim 0:33d4e66780c0 40 #include "SensorNode.hpp"
IanBenzMaxim 0:33d4e66780c0 41
IanBenzMaxim 13:6a6225690c2e 42 using namespace MaximInterface;
IanBenzMaxim 13:6a6225690c2e 43
IanBenzMaxim 0:33d4e66780c0 44 // I2C address of the MLX90614.
IanBenzMaxim 0:33d4e66780c0 45 static const uint8_t mlx90614Addr = 0xB4;
IanBenzMaxim 0:33d4e66780c0 46
IanBenzMaxim 13:6a6225690c2e 47 SensorNode::SensorNode(I2CMaster & i2c, DS2476 & ds2476)
IanBenzMaxim 13:6a6225690c2e 48 : i2c(i2c), ds28c36(MaximInterface::mbed::Sleep::instance(), i2c),
IanBenzMaxim 13:6a6225690c2e 49 ds2476(ds2476) {}
IanBenzMaxim 13:6a6225690c2e 50
IanBenzMaxim 13:6a6225690c2e 51 std::pair<SensorNode::State, error_code> SensorNode::detect() {
IanBenzMaxim 13:6a6225690c2e 52 std::pair<State, error_code> result;
IanBenzMaxim 13:6a6225690c2e 53 result.second = readRomIdAndManId(ds28c36, &romId, &manId);
IanBenzMaxim 13:6a6225690c2e 54 if (result.second || !valid(romId)) {
IanBenzMaxim 13:6a6225690c2e 55 result.first = Disconnected;
IanBenzMaxim 13:6a6225690c2e 56 return result;
IanBenzMaxim 13:6a6225690c2e 57 }
IanBenzMaxim 13:6a6225690c2e 58
IanBenzMaxim 13:6a6225690c2e 59 bool provisioned;
IanBenzMaxim 13:6a6225690c2e 60 result.second = getProvisioned(provisioned);
IanBenzMaxim 13:6a6225690c2e 61 if (result.second) {
IanBenzMaxim 13:6a6225690c2e 62 result.first = Disconnected;
IanBenzMaxim 13:6a6225690c2e 63 return result;
IanBenzMaxim 13:6a6225690c2e 64 }
IanBenzMaxim 13:6a6225690c2e 65 if (!provisioned) {
IanBenzMaxim 13:6a6225690c2e 66 result.first = NotProvisioned;
IanBenzMaxim 13:6a6225690c2e 67 return result;
IanBenzMaxim 13:6a6225690c2e 68 }
IanBenzMaxim 13:6a6225690c2e 69
IanBenzMaxim 13:6a6225690c2e 70 result.second = authenticate();
IanBenzMaxim 13:6a6225690c2e 71 if (result.second) {
IanBenzMaxim 13:6a6225690c2e 72 result.first =
IanBenzMaxim 13:6a6225690c2e 73 (result.second == make_error_code(DS28C36::AuthenticationError))
IanBenzMaxim 13:6a6225690c2e 74 ? Invalid
IanBenzMaxim 13:6a6225690c2e 75 : Disconnected;
IanBenzMaxim 13:6a6225690c2e 76 return result;
IanBenzMaxim 13:6a6225690c2e 77 }
IanBenzMaxim 13:6a6225690c2e 78
IanBenzMaxim 13:6a6225690c2e 79 bool laserEnabled;
IanBenzMaxim 13:6a6225690c2e 80 result.second = getLaserEnabled(laserEnabled);
IanBenzMaxim 13:6a6225690c2e 81 if (result.second) {
IanBenzMaxim 13:6a6225690c2e 82 result.first = Disconnected;
IanBenzMaxim 13:6a6225690c2e 83 } else {
IanBenzMaxim 13:6a6225690c2e 84 result.first = laserEnabled ? ValidLaserEnabled : ValidLaserDisabled;
IanBenzMaxim 13:6a6225690c2e 85 }
IanBenzMaxim 13:6a6225690c2e 86 return result;
IanBenzMaxim 0:33d4e66780c0 87 }
IanBenzMaxim 0:33d4e66780c0 88
IanBenzMaxim 13:6a6225690c2e 89 bool SensorNode::readTemp(TempStyle style, double & temp) {
IanBenzMaxim 13:6a6225690c2e 90 uint8_t data[2];
IanBenzMaxim 13:6a6225690c2e 91 switch (style) {
IanBenzMaxim 13:6a6225690c2e 92 case ObjectTemp:
IanBenzMaxim 13:6a6225690c2e 93 default:
IanBenzMaxim 13:6a6225690c2e 94 data[0] = 0x07;
IanBenzMaxim 13:6a6225690c2e 95 break;
IanBenzMaxim 0:33d4e66780c0 96
IanBenzMaxim 13:6a6225690c2e 97 case AmbientTemp:
IanBenzMaxim 13:6a6225690c2e 98 data[0] = 0x06;
IanBenzMaxim 13:6a6225690c2e 99 break;
IanBenzMaxim 13:6a6225690c2e 100 }
IanBenzMaxim 13:6a6225690c2e 101 error_code result = i2c.writePacket(mlx90614Addr, data, 1, false);
IanBenzMaxim 13:6a6225690c2e 102 if (result) {
IanBenzMaxim 13:6a6225690c2e 103 i2c.stop();
IanBenzMaxim 13:6a6225690c2e 104 return false;
IanBenzMaxim 13:6a6225690c2e 105 }
IanBenzMaxim 13:6a6225690c2e 106 result = i2c.readPacket(mlx90614Addr, data, 2, true);
IanBenzMaxim 13:6a6225690c2e 107 if (result) {
IanBenzMaxim 13:6a6225690c2e 108 i2c.stop();
IanBenzMaxim 13:6a6225690c2e 109 return false;
IanBenzMaxim 13:6a6225690c2e 110 }
IanBenzMaxim 13:6a6225690c2e 111 temp = ((static_cast<uint_fast16_t>(data[1]) << 8) | data[0]) * 0.02 - 273.15;
IanBenzMaxim 13:6a6225690c2e 112 return true;
IanBenzMaxim 0:33d4e66780c0 113 }
IanBenzMaxim 0:33d4e66780c0 114
IanBenzMaxim 13:6a6225690c2e 115 error_code SensorNode::getProvisioned(bool & provisioned) {
IanBenzMaxim 13:6a6225690c2e 116 return checkAuthenticatorProvisioned(ds28c36, provisioned);
IanBenzMaxim 0:33d4e66780c0 117 }
IanBenzMaxim 0:33d4e66780c0 118
IanBenzMaxim 13:6a6225690c2e 119 error_code SensorNode::provision() { return provisionAuthenticator(ds28c36); }
IanBenzMaxim 13:6a6225690c2e 120
IanBenzMaxim 13:6a6225690c2e 121 error_code SensorNode::authenticate() {
IanBenzMaxim 13:6a6225690c2e 122 // Compute slave secret on coprocessor.
IanBenzMaxim 13:6a6225690c2e 123 DS28C36::Page page;
IanBenzMaxim 13:6a6225690c2e 124 error_code result = ds28c36.readMemory(DS28C36::UserData0, page);
IanBenzMaxim 13:6a6225690c2e 125 if (result)
IanBenzMaxim 13:6a6225690c2e 126 return result;
IanBenzMaxim 13:6a6225690c2e 127 DS28C36::Page challenge = {};
IanBenzMaxim 13:6a6225690c2e 128 DS2476::PageAuthenticationData message = DS2476::createPageAuthenticationData(
IanBenzMaxim 13:6a6225690c2e 129 romId, page, challenge, DS28C36::UserData0, manId);
IanBenzMaxim 13:6a6225690c2e 130 result = ds2476.writeBuffer(message.data(), message.size());
IanBenzMaxim 13:6a6225690c2e 131 if (result)
IanBenzMaxim 13:6a6225690c2e 132 return result;
IanBenzMaxim 13:6a6225690c2e 133 result = ds2476.computeSha2UniqueSecret(DS2476::SecretNumA);
IanBenzMaxim 13:6a6225690c2e 134 if (result)
IanBenzMaxim 13:6a6225690c2e 135 return result;
IanBenzMaxim 13:6a6225690c2e 136
IanBenzMaxim 13:6a6225690c2e 137 // Compute HMAC on coprocessor.
IanBenzMaxim 13:6a6225690c2e 138 // ROM ID, Page 0, and MAN ID are already in message.
IanBenzMaxim 14:dc839a69379b 139 result = ds2476.readRng(challenge.data(), challenge.size());
IanBenzMaxim 13:6a6225690c2e 140 if (result)
IanBenzMaxim 13:6a6225690c2e 141 return result;
IanBenzMaxim 13:6a6225690c2e 142 std::copy(challenge.begin(), challenge.end(), message.begin() + 40);
IanBenzMaxim 13:6a6225690c2e 143 result = ds2476.writeBuffer(message.data(), message.size());
IanBenzMaxim 13:6a6225690c2e 144 if (result)
IanBenzMaxim 13:6a6225690c2e 145 return result;
IanBenzMaxim 13:6a6225690c2e 146 Sha256::Hash computedHmac;
IanBenzMaxim 13:6a6225690c2e 147 result = ds2476.computeSha2Hmac(computedHmac);
IanBenzMaxim 13:6a6225690c2e 148 if (result)
IanBenzMaxim 13:6a6225690c2e 149 return result;
IanBenzMaxim 13:6a6225690c2e 150
IanBenzMaxim 13:6a6225690c2e 151 // Compute HMAC on device.
IanBenzMaxim 13:6a6225690c2e 152 result = ds28c36.writeBuffer(challenge.data(), challenge.size());
IanBenzMaxim 13:6a6225690c2e 153 if (result)
IanBenzMaxim 13:6a6225690c2e 154 return result;
IanBenzMaxim 13:6a6225690c2e 155 Sha256::Hash deviceHmac;
IanBenzMaxim 13:6a6225690c2e 156 result = ds28c36.computeAndReadHmacPageAuthentication(
IanBenzMaxim 13:6a6225690c2e 157 DS28C36::UserData0, DS28C36::SecretNumA, deviceHmac);
IanBenzMaxim 13:6a6225690c2e 158 if (result)
IanBenzMaxim 13:6a6225690c2e 159 return result;
IanBenzMaxim 13:6a6225690c2e 160
IanBenzMaxim 13:6a6225690c2e 161 if (computedHmac != deviceHmac)
IanBenzMaxim 13:6a6225690c2e 162 result = make_error_code(DS28C36::AuthenticationError);
IanBenzMaxim 13:6a6225690c2e 163 return result;
IanBenzMaxim 0:33d4e66780c0 164 }
IanBenzMaxim 0:33d4e66780c0 165
IanBenzMaxim 13:6a6225690c2e 166 error_code SensorNode::setLaserEnabled(bool enabled,
IanBenzMaxim 13:6a6225690c2e 167 const PrintHandler & print) {
IanBenzMaxim 13:6a6225690c2e 168 if (print) {
IanBenzMaxim 13:6a6225690c2e 169 print((std::string(enabled ? "Enabling" : "Disabling") + " laser").c_str());
IanBenzMaxim 13:6a6225690c2e 170 }
IanBenzMaxim 13:6a6225690c2e 171
IanBenzMaxim 13:6a6225690c2e 172 // Compute write HMAC.
IanBenzMaxim 13:6a6225690c2e 173 // ROM ID and MAN ID are already in message.
IanBenzMaxim 13:6a6225690c2e 174 if (print) {
IanBenzMaxim 13:6a6225690c2e 175 print("Reading GPIO Control page");
IanBenzMaxim 13:6a6225690c2e 176 print((std::string(
IanBenzMaxim 13:6a6225690c2e 177 "Modify copy of GPIO Control page to set GPIO B state to ") +
IanBenzMaxim 13:6a6225690c2e 178 (enabled ? "conducting" : "high-impedance")).c_str());
IanBenzMaxim 13:6a6225690c2e 179 }
IanBenzMaxim 13:6a6225690c2e 180 DS28C36::Page oldPage;
IanBenzMaxim 13:6a6225690c2e 181 error_code result = ds28c36.readMemory(DS28C36::GpioControl, oldPage);
IanBenzMaxim 13:6a6225690c2e 182 if (result)
IanBenzMaxim 13:6a6225690c2e 183 return result;
IanBenzMaxim 13:6a6225690c2e 184 DS28C36::Page newPage = oldPage;
IanBenzMaxim 13:6a6225690c2e 185 newPage[1] = (enabled ? 0xAA : 0x55);
IanBenzMaxim 13:6a6225690c2e 186 const DS2476::PageAuthenticationData message =
IanBenzMaxim 13:6a6225690c2e 187 DS2476::createPageAuthenticationData(romId, oldPage, newPage,
IanBenzMaxim 13:6a6225690c2e 188 DS28C36::GpioControl, manId);
IanBenzMaxim 13:6a6225690c2e 189 if (print) {
IanBenzMaxim 13:6a6225690c2e 190 print(("Creating HMAC message (ROM ID | Old Page Data | New Page Data | "
IanBenzMaxim 13:6a6225690c2e 191 "Page # | MAN ID): " +
IanBenzMaxim 13:6a6225690c2e 192 byteArrayToHexString(&message[0], message.size())).c_str());
IanBenzMaxim 13:6a6225690c2e 193 print("Writing HMAC message to DS2476 buffer");
IanBenzMaxim 13:6a6225690c2e 194 }
IanBenzMaxim 13:6a6225690c2e 195 result = ds2476.writeBuffer(message.data(), message.size());
IanBenzMaxim 13:6a6225690c2e 196 if (result)
IanBenzMaxim 13:6a6225690c2e 197 return result;
IanBenzMaxim 13:6a6225690c2e 198 Sha256::Hash hmac;
IanBenzMaxim 13:6a6225690c2e 199 result = ds2476.computeSha2Hmac(hmac);
IanBenzMaxim 13:6a6225690c2e 200 if (result)
IanBenzMaxim 13:6a6225690c2e 201 return result;
IanBenzMaxim 13:6a6225690c2e 202
IanBenzMaxim 13:6a6225690c2e 203 if (print) {
IanBenzMaxim 13:6a6225690c2e 204 print(("DS2476 computes write authentication HMAC from slave secret "
IanBenzMaxim 13:6a6225690c2e 205 "(Secret S) and message in buffer: " +
IanBenzMaxim 13:6a6225690c2e 206 byteArrayToHexString(hmac.data(), hmac.size())).c_str());
IanBenzMaxim 13:6a6225690c2e 207 print("Write authentication HMAC is written to DS28C36 buffer");
IanBenzMaxim 13:6a6225690c2e 208 print("DS28C36 computes an HMAC to compare to the write authentication "
IanBenzMaxim 13:6a6225690c2e 209 "HMAC after receiving Page # and New Page Data");
IanBenzMaxim 13:6a6225690c2e 210 }
IanBenzMaxim 13:6a6225690c2e 211
IanBenzMaxim 13:6a6225690c2e 212 // Write page data.
IanBenzMaxim 13:6a6225690c2e 213 result = ds28c36.writeBuffer(hmac.data(), hmac.size());
IanBenzMaxim 13:6a6225690c2e 214 if (result)
IanBenzMaxim 13:6a6225690c2e 215 return result;
IanBenzMaxim 13:6a6225690c2e 216 result = ds28c36.authenticatedSha2WriteMemory(DS28C36::GpioControl,
IanBenzMaxim 13:6a6225690c2e 217 DS28C36::SecretNumA, newPage);
IanBenzMaxim 13:6a6225690c2e 218 if (result)
IanBenzMaxim 13:6a6225690c2e 219 return result;
IanBenzMaxim 13:6a6225690c2e 220 if (print) {
IanBenzMaxim 13:6a6225690c2e 221 print("DS28C36 updates page data which changes GPIO B state");
IanBenzMaxim 13:6a6225690c2e 222 print((std::string("Laser is now ") + (enabled ? "enabled" : "disabled"))
IanBenzMaxim 13:6a6225690c2e 223 .c_str());
IanBenzMaxim 13:6a6225690c2e 224 }
IanBenzMaxim 13:6a6225690c2e 225 return result;
IanBenzMaxim 0:33d4e66780c0 226 }
IanBenzMaxim 0:33d4e66780c0 227
IanBenzMaxim 13:6a6225690c2e 228 error_code SensorNode::getLaserEnabled(bool & enabled) {
IanBenzMaxim 13:6a6225690c2e 229 DS28C36::Page page;
IanBenzMaxim 13:6a6225690c2e 230 const error_code result = ds28c36.readMemory(DS28C36::GpioControl, page);
IanBenzMaxim 13:6a6225690c2e 231 if (!result)
IanBenzMaxim 0:33d4e66780c0 232 enabled = (page[1] == 0xAA);
IanBenzMaxim 13:6a6225690c2e 233 return result;
IanBenzMaxim 0:33d4e66780c0 234 }