#define RSA_PUBLIC_EXP  65537
bool hashlib_RSAEncrypt(const uint8_t* msg, size_t msglen, uint8_t *ct, const uint8_t* pubkey, size_t keylen){
    if(msg==NULL || pubkey==NULL) return false;
    if(msglen != keylen) return false;
    uint8_t spos = 0;
    while(pubkey[spos++]==0) ct[spos] = 0;
    hashlib_RSAEncodeOAEP(msg, msglen, &ct[spos], keylen-spos, NULL)
    powmod((uint8_t)keylen, ct, RSA_PUBLIC_EXP, pubkey);
    return true;
}