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Arm Mbed TLS provides a comprehensive SSL/TLS solution and makes it easy for developers to include cryptographic and SSL/TLS capabilities in their software and embedded products. As an SSL library, it provides an intuitive API, readable source code and a minimal and highly configurable code footprint.

Note: Mbed TLS needs a secure source of random numbers; make sure that your target board has one and that it is fully ported to Arm Mbed OS. You can read more about this in our porting guide.

Mbed TLS examples

You can try the following examples:

  1. TLS client: Downloads a file from an HTTPS server (os.mbed.com) and looks for a specific string in that file.

  2. Benchmark: Measures the time taken to perform basic cryptographic functions used in the library.

  3. Hashing: Demonstrates the various APIs for computing hashes of data (also known as message digests) with SHA-256.

  4. Authenticated encryption: Demonstrates using the Cipher API for encrypting and authenticating data with AES-CCM.

Each of them comes with complete usage instructions as a readme file in the repository.

Configuring Mbed TLS features

Mbed TLS simplifies enabling and disabling features to meet the needs of a particular project, through compilation options. The list of compilation flags is available in the fully documented configuration file, config.h.

For example, in an application called myapp, if you want to enable the EC J-PAKE key exchange and disable the CBC cipher mode, you can create a file named mbedtls-config-changes.h in the myapp directory containing the following lines:



Then create a file named mbed_app.json at the root of your application with the following contents:

    "macros": ["MBEDTLS_USER_CONFIG_FILE=\"mbedtls-config-changes.h\""]

Other resources

The Mbed TLS website contains many other useful resources for developers, such as developer documentation, knowledge base articles and a support forum.

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