Sha256 Hashes in Modelica

Here’s the translation of the SHA256 Hashes example to Modelica, formatted in Markdown suitable for Hugo:

In Modelica, cryptographic operations are not part of the standard library. However, we can demonstrate the concept using an external C function. This example shows how to compute SHA256 hashes in Modelica by calling an external C function.

model SHA256Hashes
  function sha256
    input String message;
    output String hash;
    external "C" sha256(message, hash) annotation(Include="#include <openssl/sha.h>");
  end sha256;

equation
  when initial() then
    String s = "sha256 this string";
    String hash = sha256(s);
    Modelica.Utilities.Streams.print(s);
    Modelica.Utilities.Streams.print(hash);
  end when;
end SHA256Hashes;

In this example, we define an external function sha256 that uses the OpenSSL library to compute the SHA256 hash. The sha256 function takes a string input and returns the hash as a string.

The when initial() clause ensures that the hash computation is performed only once at the start of the simulation.

To use this model:

1. Make sure you have OpenSSL development libraries installed on your system.
2. Compile and link your Modelica code with the OpenSSL library.
3. Run the simulation.

The program will compute the hash and print it.

sha256 this string
1af1dfa857bf1d8814fe1af8983c18080019922e557f15a8a...

Note that this is a simplified example. In a real-world scenario, you would need to handle potential errors, ensure proper memory management, and consider the specific requirements of your Modelica simulation environment.

Also, if you need cryptographically secure hashes, you should carefully research hash strength and consider using more recent hash functions if appropriate for your use case.