ftu/main.c

#include <stdio.h>
#include <string.h>
#include <time.h>
#include "blst/blst.h"

const byte dst[] = "MY-DST";
double time_taken;
clock_t t;

void printbytes(byte *toprint, int length){
    for(int i=0;i<length;i++){
        printf("%.2x ", toprint[i]);
    }
    printf("\n");
}

void signer(byte *compressed_signature, byte *compressed_public_key, byte *msg){
    blst_scalar sk;
    blst_p2 pk;
    blst_p1 hash, signature;
    byte debug_print_buf[256];
    byte myikm[32] = {'*', '*', '*', '*', '*', '*', '*', '*', '*', '*', '*', '*', '*', '*', '*', '*', '*', '*', '*', '*', '*', '*', '*', '*', '*', '*', '*', '*', '*', '*', '*', '*'};

    // On signer's side:
    printf("IKM: ");
    printbytes(myikm, 32);

    blst_keygen(&sk, myikm, 32, 0, 0);

    blst_bendian_from_scalar(debug_print_buf, &sk);
    printf("Secret Key: ");
    printbytes(debug_print_buf, 32);

    blst_sk_to_pk_in_g2(&pk, &sk);

    blst_p2_compress(compressed_public_key, &pk);
    printf("Compressed Public Key: ");
    printbytes(compressed_public_key, 96);

    t = clock();
    blst_hash_to_g1(&hash, msg, strlen((char *) msg), dst, strlen((char *) dst), 0, 0);
    t = clock() - t;

    time_taken = ((double)t)/CLOCKS_PER_SEC*1000.0;
    printf("blst_hash_to_g1 took %f ms\n", time_taken);

    blst_p1_serialize(debug_print_buf, &hash);
    printf("Message Hash: ");
    printbytes(debug_print_buf, 96);

    t = clock();
    blst_sign_pk_in_g2(&signature, &hash, &sk);
    t = clock() - t;

    time_taken = ((double)t)/CLOCKS_PER_SEC*1000.0;
    printf("blst_sign_pk_in_g2 took %f ms\n", time_taken);

    blst_p1_serialize(debug_print_buf, &signature);
    printf("Signature: ");
    printbytes(debug_print_buf, 96);

    blst_p1_compress(compressed_signature, &signature);
    printf("Compressed Signature: ");
    printbytes(compressed_signature, 48);
}

void verifier(byte *compressed_signature, byte *compressed_public_key, byte *msg){
    blst_p1_affine sig;
    blst_p2_affine pk;

    blst_p1_uncompress(&sig, compressed_signature);
    blst_p2_uncompress(&pk, compressed_public_key);

    BLST_ERROR returned;

    // TODO: check if in g2 group
    
    t = clock();
    returned = blst_core_verify_pk_in_g2(&pk, &sig, 1, msg, strlen((char *) msg), dst, strlen((char *) dst), 0, 0);
    t = clock() - t;

    time_taken = ((double)t)/CLOCKS_PER_SEC*1000.0;
    printf("blst_core_verify_pk_in_g2 took %f ms\n", time_taken);

    if(returned == BLST_SUCCESS){
        printf("Verified!\n");
    }else{
        printf("Not verified!\n");
    }
}

int main(){
    byte compressed_signature[48];
    byte compressed_public_key[96];
    byte msg[] = "assertion";

    t = clock();
    t = clock() - t;

    time_taken = ((double)t)/CLOCKS_PER_SEC*1000.0;
    printf("Doing nothing took %f ms\n", time_taken);

    printf("msg is now %s\n", msg);

    // Sign the message and get the results back
    signer(compressed_signature, compressed_public_key, msg);

    //msg[8] = 'A';

    printf("msg is now %s\n", msg);

    // Now on verifier's side (after compressed_signature, serialized_public_key, and msg are passed over the network)
    verifier(compressed_signature, compressed_public_key, msg);
}