// ESP32 HMAC SHA-256
// https://emn178.github.io/online-tools/sha256.html

// Hello, World!
// dffd6021bb2bd5b0af676290809ec3a53191dd81c7f70a4b28688a362182986f

// https://wokwi.com/projects/407044309018040321 - ESP32 SHA-256 Accelerator Test (MicroPython)
// https://wokwi.com/projects/407045956475773953 - ESP32 SHA-256 (C Algoritm)

#include "mbedtls/md.h"

void md_sha256(const char* inputString, const uint16_t len, uint8_t* outputHash) {
	mbedtls_md_context_t context;
  mbedtls_md_type_t md_type = MBEDTLS_MD_SHA256;
  mbedtls_md_init(&context);
  mbedtls_md_setup(&context, mbedtls_md_info_from_type(md_type), 1);	// 0 - HMAC Off, 1 - HMAC on
  mbedtls_md_starts(&context);
  mbedtls_md_update(&context, (const unsigned char*)inputString, len);
  mbedtls_md_finish(&context, outputHash);
  mbedtls_md_free(&context);
}

void md_ripemd160(const char* inputString, const uint16_t len, uint8_t* outputHash) {
	mbedtls_md_context_t context;
  mbedtls_md_type_t md_type = MBEDTLS_MD_RIPEMD160;
  mbedtls_md_init(&context);
  mbedtls_md_setup(&context, mbedtls_md_info_from_type(md_type), 1);	// 0 - HMAC Off, 1 - HMAC on
  mbedtls_md_starts(&context);
  mbedtls_md_update(&context, (const unsigned char*)inputString, len);
  mbedtls_md_finish(&context, outputHash);
  mbedtls_md_free(&context);
}

void printHex(uint8_t *data, size_t len) {
  for(uint16_t i=0; i<len; i++) {
		char str[3];
		sprintf(str, "%02x", (uint16_t)data[i]);
		Serial.print(str);
	}
}

void setup() {
	Serial.begin(115200);
	Serial.println();
	
	char* input = "Hello, World!";
	Serial.println(input);
	uint16_t len = strlen(input);	// len = 13
	uint8_t hash[32];
	uint64_t time = micros();
	md_sha256(input, len, hash);
	time = micros()-time;
	printHex(hash, 32);
	Serial.printf("\nTime: %llu us", time);		// Time: 262 us
	
	Serial.println("\n");
	Serial.println(input);
	uint8_t hash2[32];
	time = micros();
	md_sha256(input, len, hash2);
	time = micros()-time;
	printHex(hash2, 32);
	Serial.printf("\nTime: %llu us", time);		// Time: 284 us
	
	Serial.println("\n");
	Serial.println(input);
	uint8_t ripemd[20];
	time = micros();
	md_ripemd160(input, len, ripemd);
	time = micros()-time;
	printHex(ripemd, 20);
	Serial.printf("\nTime: %llu us", time);		// Time: 20 us
}

void loop() {}