These are simulators for silicon so that wolfSSL can easily regression test for issues with integrations.
The SE050Sim is a simulators for the SE050 which covers basic ECC and RSA functionality.
The ATECC608Sim is a simulator for the Microchip ATECC608A that covers the wolfSSL-required ATCA command subset: P-256 ECDSA, ECDH, SHA-256, RNG, and Config/OTP/Data zone state. It plugs into cryptoauthlib via a custom TCP HAL.
The STSAFEA120Sim is a simulator for the STMicroelectronics STSAFE-A120 that covers the wolfSSL-required STSAFE-A command subset: P-256 ECDSA, ECDH, RNG, and a slot/zone store with a default device certificate. It plugs into ST's open-source STSELib middleware via a custom Linux PAL that pipes the I2C transport over TCP.
The TROPIC01Sim is a simulator for the Tropic Square TROPIC01
secure element. It speaks libtropic's "TROPIC01 Model" wire protocol over
TCP and performs the full Noise_KK1_25519_AESGCM_SHA256 secure-channel
handshake, then answers the L3 commands the wolfSSL TROPIC01 port exercises:
RNG, ECC keygen/read for P-256 + Ed25519, R-memory read/write, and the
pairing-key surface. The simulator is consumed unmodified by libtropic via
its hal/posix/tcp/ HAL.
The STM32Sim is a Unicorn-Engine-based simulator for STM32 microcontrollers focused on the on-chip cryptographic accelerators (CRYP/AES, HASH, RNG, PKA) that wolfSSL uses. It is intended to replace the Renode-based CI flow for wolfSSL on STM32 targets and to close the gaps Renode has in hardware-crypto modelling (HASH peripheral, full AES mode set, PKA).