masterthesis-ecdaa-network-wrapper/verifier.c

#include "verifier.h"

typedef enum verifierstate {
    ON,
    ASKISSUER,
    GOTISSUER,
    ASKATTEST,
} verifierstate_e;

typedef struct verifier {
    struct ecdaa_issuer_public_key_FP256BN ipk;
//    struct ecdaa_member_public_key_FP256BN mpk;
    struct ecdaa_revocations_FP256BN revocations;
    verifierstate_e state;
} verifier_t;

verifier_t verifier;

int verifier_getissuer(char *buffer);

//int verifier_getmember(char *buffer);
int verifier_attestmember(char *buffer);

int verifier_checklink(char *buffer);

int verifier_checkattest(char *buffer);

int main() {
    verifier.revocations.sk_list = NULL;
    verifier.revocations.bsn_list = NULL;

    if (2 != server_start(&process_verifier, VERIFIERPORT)) {
        printf("server failed\n");
    }
    return 0;
}

int process_verifier(char *buffer) {
    int ret = 0;

    printf("> VERIFIER: %s\n", buffer);

    if (0 == strncasecmp("VERIFY", buffer, 6)) {
        switch (verifier.state) {
            case GOTISSUER:
                bzero(buffer, MAX_BUFSIZE);
                strncpy(buffer, "OK\n", 3);
                break;
            default:
                bzero(buffer, MAX_BUFSIZE);
                strncpy(buffer, "ERR\n", 4);
        }
    } else if (0 == strncasecmp("ATTEST", buffer, 4)) {
        ret = client_connect(&verifier_attestmember, MEMBERIP, MEMBERPORT);
        if (0 >= ret) {
            printf("process_verifier: member verification failed\n");
            bzero(buffer, MAX_BUFSIZE);
            strncpy(buffer, "ERR\n", 4);
        } else {
            bzero(buffer, MAX_BUFSIZE);
            strncpy(buffer, "OK\n", 3);
        }
        ret = 0;
    } else if (0 == strncasecmp("LINK", buffer, 4)) {
        bzero(buffer, MAX_BUFSIZE);
        verifier_checklink(buffer);
    } else if (0 == strncasecmp("GETPUBLIC", buffer, 9)) {
        verifier.state = ON;
        ret = client_connect(&verifier_getissuer, ISSUERIP, ISSUERPORT);
        if (0 >= ret || GOTISSUER != verifier.state) {
            printf("process_verifier: issuer connection failed\n");
            bzero(buffer, MAX_BUFSIZE);
            strncpy(buffer, "ERR\n", 4);
        } else {
            bzero(buffer, MAX_BUFSIZE);
            strncpy(buffer, "OK\n", 3);
        }
        ret = 0;
    } else if (0 == strncasecmp("EXIT", buffer, 4)) {
        printf("exit()\n");
        bzero(buffer, MAX_BUFSIZE);
        strncpy(buffer, "OK\n", 3);
        ret = 1;
    } else if (0 == strncasecmp("SHUTDOWN", buffer, 8)) {
        bzero(buffer, MAX_BUFSIZE);
        strncpy(buffer, "OK\n", 3);
        ret = 2;
    } else {
        printf("error()\n");
        bzero(buffer, MAX_BUFSIZE);
        strncpy(buffer, "ERR\n", 4);
        ret = 0;
    }

    printf("< VERIFIER: %s\n", buffer);
    return ret;
}

int verifier_getissuer(char *buffer) {
    int ret = 0;

    switch (verifier.state) {
        case ON:
            bzero(buffer, MAX_BUFSIZE);
            strncpy(buffer, "PUBLISH\n", 8);
            verifier.state = ASKISSUER;
            break;
        case ASKISSUER:
            if (0 == strncasecmp("PUBLISH", buffer, 7)) {
                printf("ISSUER > VERIFIER: %s", buffer);
                uint8_t binbuf[MAX_BUFSIZE];
                char *current = &buffer[8];
                ecdaa_hextobin(current, binbuf, ECDAA_ISSUER_PUBLIC_KEY_FP256BN_LENGTH);
                ret = ecdaa_issuer_public_key_FP256BN_deserialize(&verifier.ipk, binbuf);
                if (-1 == ret) {
                    printf("verifier_getpublic: issuer public key is malformed!\n");
                    ret = -1;
                } else if (-2 == ret) {
                    printf("verifier_getpublic: signature of issuer public key is invalid\n");
                    ret = -1;
                } else {
                    verifier.state = GOTISSUER;
                    ret = 1;
                }
            } else {
                printf("verifier_getpublic: did not get public key from issuer\n");
                verifier.state = ON;
                ret = -1;
            }
            break;
        default:
            ret = -1;
    }
    if (0 == ret) {
        printf("ISSUER < VERIFIER: %s", buffer);
    }
    return ret;
}


//"ATTEST" > "OK"
int verifier_attestmember(char *buffer) {
    int ret = 0;

    switch (verifier.state) {
        case GOTISSUER:
            bzero(buffer, MAX_BUFSIZE);
            strncpy(buffer, "ATTEST\n", 7);
            verifier.state = ASKATTEST;
            break;
        case ASKATTEST:
            if (0 == strncasecmp("ATTEST", buffer, 6)) {
                printf("MEMBER > VERIFIER: %s", buffer);
                ret = verifier_checkattest(buffer);
                if (-1 == ret) {
                    printf("verifier_attestmember: member public key is malformed!\n");
                    ret = -1;
                } else if (-2 == ret) {
                    printf("verifier_attestmember: signature of member public key is invalid\n");
                    ret = -1;
                } else {
                    verifier.state = GOTISSUER;
                    ret = 1;
                }
            } else {
                printf("verifier_attestmember: did not get correct message from member\n");
                ret = -1;
            }
            break;
        default:
            ret = -1;
    }
    if (0 == ret) {
        printf("MEMBER < VERIFIER: %s", buffer);
    }
    return ret;
}

//"ATTEST <msg>0<signature w/o bsn>" or
//"ATTEST <msg>1<signature with bsn>"
int verifier_checkattest(char *buffer) {
    char *current = &buffer[7]; //"ATTEST "

    char msg[MAX_MSGSIZE];
    strncpy(msg, current, MAX_MSGSIZE);
    size_t msg_len = strlen(msg);
    current = &current[MAX_MSGSIZE];

    int has_nym = current[0] - '0';
    current = &current[1];

    char bsn[MAX_BSNSIZE];
    bzero(bsn, MAX_BSNSIZE);
    size_t bsn_len = 0;

    uint8_t binbuf[MAX_BUFSIZE];
    bzero(binbuf, MAX_BUFSIZE);

    if (has_nym) {
        strncpy(bsn, current, MAX_BSNSIZE);
        bsn_len = strlen(bsn);
        current = &current[MAX_BSNSIZE];
    }
    int sig_len = has_nym ? ECDAA_SIGNATURE_FP256BN_WITH_NYM_LENGTH : ECDAA_SIGNATURE_FP256BN_LENGTH;
    ecdaa_hextobin(current, binbuf, sig_len);

    struct ecdaa_signature_FP256BN sig;
    int ret = ecdaa_signature_FP256BN_deserialize(&sig, binbuf, has_nym);
    if (0 != ret) {
        printf("verifier_checkattest: error reading signature\n");
        return -1;
    }

    printf("verifier_checkattest: msg: %s, len: %lu\n",msg, msg_len);
    printf("verifier_checkattest: bsn: %s, len: %lu\n",bsn, bsn_len);
    printf("verifier_checkattest: sig: %s", current);
    ret = ecdaa_signature_FP256BN_verify(&sig, &verifier.ipk.gpk, &verifier.revocations, (uint8_t *) msg, msg_len,
                                         (uint8_t *) bsn, bsn_len);
    if (0 != ret) {
        printf("verifier_checkattest: signature not valid\n");
        return -1;
    }

    return 0;
}

//"LINK" > "NOT IMPLEMENTED"
int verifier_checklink(char *buffer) {
    strncat(buffer, "NOT_IMPLEMENTED\n", 17);
    return 0;
}