70 lines
2.8 KiB
Markdown
70 lines
2.8 KiB
Markdown
# Authenticated encryption example
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This application performs authenticated encryption and authenticated decryption of a buffer. It serves as a tutorial for the basic authenticated encryption functions of mbed TLS.
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## Pre-requisites
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To build and run this example the requirements below are necessary:
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* A computer with the following software installed:
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* [CMake](http://www.cmake.org/download/).
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* [yotta](https://github.com/ARMmbed/yotta). Please note that **yotta has its own set of dependencies**, listed in the [installation instructions](http://armmbed.github.io/yotta/#installing-on-windows).
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* [Python](https://www.python.org/downloads/).
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* [ARM GCC toolchain](https://launchpad.net/gcc-arm-embedded).
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* A serial terminal emulator (e.g. screen, pySerial, cu).
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* An [FRDM-K64F](http://developer.mbed.org/platforms/FRDM-K64F/) development board, or another board supported by mbed OS (in that case you'll have to substitute frdm-k64f-gcc with the appropriate target below).
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* A micro-USB cable.
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* If your OS is Windows, please follow the installation instructions [for the serial port driver](https://developer.mbed.org/handbook/Windows-serial-configuration).
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## Getting started
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1. Connect the FRDM-K64F to the computer with the micro-USB cable, being careful to use the micro-usb port labeled "OpenSDA".
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2. Navigate to the mbedtls directory supplied with your release and open a terminal.
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3. Set the yotta target:
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```
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yotta target frdm-k64f-gcc
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```
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4. Check that there are no missing dependencies:
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```
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$ yt ls
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```
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If there are, yotta will list them in the terminal. Please install them before proceeding.
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5. Build mbedtls and the examples. This will take a long time if it is the first time:
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```
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$ yt build
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```
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6. Copy `build/frdm-k64f-gcc/test/mbedtls-test-example-authcrypt.bin` to your mbed board and wait until the LED next to the USB port stops blinking.
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7. Start the serial terminal emulator and connect to the virtual serial port presented by FRDM-K64F. For settings, use 9600 baud, 8N1, no flow control.
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8. Press the reset button on the board.
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9. The output in the terminal window should look like:
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```
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{{timeout;10}}
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{{host_test_name;default}}
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{{description;mbed TLS example authcrypt}}
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{{test_id;MBEDTLS_EX_AUTHCRYPT}}
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{{start}}
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plaintext message: 536f6d65207468696e67732061726520626574746572206c65667420756e7265616400
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ciphertext: c57f7afb94f14c7977d785d08682a2596bd62ee9dcf216b8cccd997afee9b402f5de1739e8e6467aa363749ef39392e5c66622b01c7203ec0a3d14
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decrypted: 536f6d65207468696e67732061726520626574746572206c65667420756e7265616400
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DONE
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{{success}}
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{{end}}
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```
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The actual output for the ciphertext line will vary on each run due to the use of a random nonce in the encryption process.
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