Module esp32_hal::rsa

RSA Accelerator support.

Overview

The RSA driver provides a set of functions to accelerate RSA (Rivest–Shamir–Adleman) cryptographic operations on ESP chips. RSA is a widely used public-key cryptographic algorithm that involves complex mathematical computations, and the RSA accelerator on ESP chips is designed to optimize these computations for faster performance.

Implementation details;

• The driver uses low-level peripheral access to read and write data from/to the RSA peripheral.
• The driver contains unsafe code blocks as it directly manipulates memory addresses for data transfer.
• The driver supports different sizes of operands based on the generic types provided during instantiation.
• The nb crate is used to handle non-blocking operations.
• The driver provides a set of high-level abstractions to simplify RSA cryptographic operations on ESP chips, allowing developers to leverage the RSA accelerator for improved performance.

Examples

Initialization

let peripherals = Peripherals::take();
let mut system = peripherals.SYSTEM.split();

let mut rsa = Rsa::new(peripherals.RSA);

Async (modular exponentiation)

#[embassy_executor::task]
async fn mod_exp_example(mut rsa: Rsa<'static>) {
    let mut outbuf = [0_u32; U512::LIMBS];
    let mut mod_exp = RsaModularExponentiation::<operand_sizes::Op512>::new(
        &mut rsa,
        BIGNUM_2.as_words(),
        BIGNUM_3.as_words(),
        compute_mprime(&BIGNUM_3),
    );
    let r = compute_r(&BIGNUM_3);
    let base = &BIGNUM_1.as_words();
    mod_exp
        .exponentiation(base, r.as_words(), &mut outbuf)
        .await;
    let residue_params = DynResidueParams::new(&BIGNUM_3);
    let residue = DynResidue::new(&BIGNUM_1, residue_params);
    let sw_out = residue.pow(&BIGNUM_2);
    assert_eq!(U512::from_words(outbuf), sw_out.retrieve());
    println!("modular exponentiation done");
}

This peripheral supports async on every available chip except of esp32 (to be solved).

⚠️: The examples for RSA peripheral are quite extensive, so for a more detailed study of how to use this driver please visit the repository with corresponding example.

Modules

• operand_sizes
  Marker types for the operand sizes

Structs

• Rsa
  RSA peripheral container
• RsaModularExponentiation
  Support for RSA peripheral’s modular exponentiation feature that could be used to find the (base ^ exponent) mod modulus.
• RsaModularMultiplication
  Support for RSA peripheral’s modular multiplication feature that could be used to find the (operand a * operand b) mod modulus.
• RsaMultiplication
  Support for RSA peripheral’s large number multiplication feature that could be used to find the operand a * operand b.