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.

src/Bitmap.cpp@16:a004191a79ab, 2019-10-03 (annotated)

Committer:
IanBenzMaxim
Date:
Thu Oct 03 11:40:13 2019 -0500
Revision:
16:a004191a79ab
Parent:
Bitmap.cpp@13:6a6225690c2e 
Updated MaximInterface to version 2.0. Updated mbed-os to version 5.5.7. Cleaned up code styling.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
IanBenzMaxim 0:33d4e66780c0 1 /*******************************************************************************
IanBenzMaxim 16:a004191a79ab 2 * Copyright (C) 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 <algorithm>
IanBenzMaxim 0:33d4e66780c0 34 #include "Bitmap.hpp"
IanBenzMaxim 0:33d4e66780c0 35
IanBenzMaxim 0:33d4e66780c0 36 static const int minWidthHeight = 1;
IanBenzMaxim 11:989eabe2a376 37 static const int pixelsPerSegment = 8;
IanBenzMaxim 0:33d4e66780c0 38
IanBenzMaxim 0:33d4e66780c0 39 template <typename T>
IanBenzMaxim 13:6a6225690c2e 40 static T divideRoundUp(const T dividend, const T divisor) {
IanBenzMaxim 13:6a6225690c2e 41 return (dividend / divisor) + (((dividend % divisor) == 0) ? 0 : 1);
IanBenzMaxim 0:33d4e66780c0 42 }
IanBenzMaxim 0:33d4e66780c0 43
IanBenzMaxim 13:6a6225690c2e 44 static int calculateSegmentsPerLine(int width) {
IanBenzMaxim 13:6a6225690c2e 45 return divideRoundUp(width, pixelsPerSegment);
IanBenzMaxim 11:989eabe2a376 46 }
IanBenzMaxim 11:989eabe2a376 47
IanBenzMaxim 13:6a6225690c2e 48 static int calculateHeight(size_t size, int width) {
IanBenzMaxim 16:a004191a79ab 49 return divideRoundUp<size_t>(size, calculateSegmentsPerLine(width));
IanBenzMaxim 11:989eabe2a376 50 }
IanBenzMaxim 11:989eabe2a376 51
IanBenzMaxim 13:6a6225690c2e 52 static int calculateSegmentIndex(int x, int y, int width) {
IanBenzMaxim 13:6a6225690c2e 53 return y * calculateSegmentsPerLine(width) + x / pixelsPerSegment;
IanBenzMaxim 0:33d4e66780c0 54 }
IanBenzMaxim 0:33d4e66780c0 55
IanBenzMaxim 16:a004191a79ab 56 static unsigned int calculatePixelMask(int x) {
IanBenzMaxim 13:6a6225690c2e 57 return 1 << (pixelsPerSegment - 1 - (x % pixelsPerSegment));
IanBenzMaxim 11:989eabe2a376 58 }
IanBenzMaxim 11:989eabe2a376 59
IanBenzMaxim 13:6a6225690c2e 60 Bitmap::Bitmap(int width, int height)
IanBenzMaxim 16:a004191a79ab 61 : width_(std::max(width, minWidthHeight)),
IanBenzMaxim 16:a004191a79ab 62 height_(std::max(height, minWidthHeight)),
IanBenzMaxim 16:a004191a79ab 63 data_(calculateSegmentsPerLine(width_) * height_, 0x00) {}
IanBenzMaxim 11:989eabe2a376 64
IanBenzMaxim 13:6a6225690c2e 65 Bitmap::Bitmap(const uint8_t * data, size_t size, int width)
IanBenzMaxim 16:a004191a79ab 66 : width_(std::max(width, minWidthHeight)),
IanBenzMaxim 16:a004191a79ab 67 height_(std::max(calculateHeight(size, width), minWidthHeight)),
IanBenzMaxim 16:a004191a79ab 68 data_(calculateSegmentsPerLine(width_) * height_, 0x00) {
IanBenzMaxim 16:a004191a79ab 69 std::copy(data, data + size, data_.begin());
IanBenzMaxim 0:33d4e66780c0 70 }
IanBenzMaxim 0:33d4e66780c0 71
IanBenzMaxim 13:6a6225690c2e 72 bool Bitmap::pixelEnabled(int x, int y) const {
IanBenzMaxim 13:6a6225690c2e 73 bool enabled = false;
IanBenzMaxim 16:a004191a79ab 74 if ((x >= 0) && (x < width_) && (y >= 0) && (y < height_)) {
IanBenzMaxim 13:6a6225690c2e 75 enabled =
IanBenzMaxim 16:a004191a79ab 76 data_[calculateSegmentIndex(x, y, width_)] & calculatePixelMask(x);
IanBenzMaxim 13:6a6225690c2e 77 }
IanBenzMaxim 13:6a6225690c2e 78 return enabled;
IanBenzMaxim 0:33d4e66780c0 79 }
IanBenzMaxim 0:33d4e66780c0 80
IanBenzMaxim 13:6a6225690c2e 81 void Bitmap::setPixelEnabled(int x, int y, bool enabled) {
IanBenzMaxim 16:a004191a79ab 82 if ((x >= 0) && (x < width_) && (y >= 0) && (y < height_)) {
IanBenzMaxim 16:a004191a79ab 83 uint8_t & dataSegment = data_[calculateSegmentIndex(x, y, width_)];
IanBenzMaxim 16:a004191a79ab 84 const unsigned int dataMask = calculatePixelMask(x);
IanBenzMaxim 13:6a6225690c2e 85 if (enabled) {
IanBenzMaxim 13:6a6225690c2e 86 dataSegment |= dataMask;
IanBenzMaxim 13:6a6225690c2e 87 } else {
IanBenzMaxim 13:6a6225690c2e 88 dataSegment &= ~dataMask;
IanBenzMaxim 0:33d4e66780c0 89 }
IanBenzMaxim 13:6a6225690c2e 90 }
IanBenzMaxim 0:33d4e66780c0 91 }
IanBenzMaxim 0:33d4e66780c0 92
IanBenzMaxim 13:6a6225690c2e 93 void Bitmap::overlay(int x, int y, const uint8_t * data, size_t size,
IanBenzMaxim 13:6a6225690c2e 94 int width) {
IanBenzMaxim 13:6a6225690c2e 95 if (width < minWidthHeight) {
IanBenzMaxim 13:6a6225690c2e 96 return;
IanBenzMaxim 13:6a6225690c2e 97 }
IanBenzMaxim 11:989eabe2a376 98
IanBenzMaxim 13:6a6225690c2e 99 const int segmentsPerLine = calculateSegmentsPerLine(width);
IanBenzMaxim 16:a004191a79ab 100 for (size_t segment = 0; segment < size; ++segment) {
IanBenzMaxim 13:6a6225690c2e 101 const int curY = segment / segmentsPerLine;
IanBenzMaxim 16:a004191a79ab 102 if (!((y + curY) < height_)) {
IanBenzMaxim 13:6a6225690c2e 103 break;
IanBenzMaxim 0:33d4e66780c0 104 }
IanBenzMaxim 16:a004191a79ab 105 for (int pixel = 0; pixel < pixelsPerSegment; ++pixel) {
IanBenzMaxim 13:6a6225690c2e 106 const int curX = (segment % segmentsPerLine) * pixelsPerSegment + pixel;
IanBenzMaxim 16:a004191a79ab 107 if (!(((x + curX) < width_) && (curX < width))) {
IanBenzMaxim 13:6a6225690c2e 108 break;
IanBenzMaxim 13:6a6225690c2e 109 }
IanBenzMaxim 13:6a6225690c2e 110 setPixelEnabled(x + curX, y + curY,
IanBenzMaxim 13:6a6225690c2e 111 data[segment] & (1 << (pixelsPerSegment - 1 - pixel)));
IanBenzMaxim 13:6a6225690c2e 112 }
IanBenzMaxim 13:6a6225690c2e 113 }
IanBenzMaxim 0:33d4e66780c0 114 }
IanBenzMaxim 10:71359af61af8 115
IanBenzMaxim 13:6a6225690c2e 116 void Bitmap::overlay(int x, int y, const Bitmap & src) {
IanBenzMaxim 16:a004191a79ab 117 overlay(x, y, &src.data_[0], src.data_.size(), src.width_);
IanBenzMaxim 10:71359af61af8 118 }
IanBenzMaxim 10:71359af61af8 119
IanBenzMaxim 16:a004191a79ab 120 void Bitmap::clear() { std::fill(data_.begin(), data_.end(), 0); }
IanBenzMaxim 13:6a6225690c2e 121
IanBenzMaxim 13:6a6225690c2e 122 void Bitmap::clear(int x, int y, int width, int height) {
IanBenzMaxim 16:a004191a79ab 123 if (!((x >= 0) && (x < width_) && (y >= 0) && (y < height_))) {
IanBenzMaxim 13:6a6225690c2e 124 return;
IanBenzMaxim 13:6a6225690c2e 125 }
IanBenzMaxim 16:a004191a79ab 126 if ((x + width) > width_) {
IanBenzMaxim 16:a004191a79ab 127 width = width_ - x;
IanBenzMaxim 13:6a6225690c2e 128 }
IanBenzMaxim 16:a004191a79ab 129 if ((y + height) > height_) {
IanBenzMaxim 16:a004191a79ab 130 height = height_ - y;
IanBenzMaxim 13:6a6225690c2e 131 }
IanBenzMaxim 13:6a6225690c2e 132
IanBenzMaxim 13:6a6225690c2e 133 const int startX = x;
IanBenzMaxim 13:6a6225690c2e 134 const int startY = y;
IanBenzMaxim 13:6a6225690c2e 135 while (y < (startY + height)) {
IanBenzMaxim 13:6a6225690c2e 136 x = startX;
IanBenzMaxim 13:6a6225690c2e 137 while (x < (startX + width)) {
IanBenzMaxim 13:6a6225690c2e 138 if (((x % pixelsPerSegment) == 0) &&
IanBenzMaxim 13:6a6225690c2e 139 ((x + pixelsPerSegment) < (startX + width))) {
IanBenzMaxim 16:a004191a79ab 140 data_[calculateSegmentIndex(x, y, width_)] = 0;
IanBenzMaxim 13:6a6225690c2e 141 x += pixelsPerSegment;
IanBenzMaxim 13:6a6225690c2e 142 } else {
IanBenzMaxim 13:6a6225690c2e 143 setPixelEnabled(x, y, false);
IanBenzMaxim 16:a004191a79ab 144 ++x;
IanBenzMaxim 13:6a6225690c2e 145 }
IanBenzMaxim 10:71359af61af8 146 }
IanBenzMaxim 16:a004191a79ab 147 ++y;
IanBenzMaxim 13:6a6225690c2e 148 }
IanBenzMaxim 10:71359af61af8 149 }