const STACK_OF(X509_EXTENSION) *exts;
    Tcl_Obj *listPtr = Tcl_NewListObj(0, NULL);

    if (listPtr == NULL) {
	return NULL;
    }

    if ((exts = X509_get0_extensions(cert)) != NULL) {
	for (int i=0; i < X509_get_ext_count(cert); i++) {
	    X509_EXTENSION *ex = sk_X509_EXTENSION_value(exts, i);
	    ASN1_OBJECT *obj = X509_EXTENSION_get_object(ex);
	    /* ASN1_OCTET_STRING *data = X509_EXTENSION_get_data(ex); */
	    int critical = X509_EXTENSION_get_critical(ex);
	    LAPPEND_BOOL(interp, listPtr, OBJ_nid2ln(OBJ_obj2nid(obj)), critical);
	}
    }
    return listPtr;
}

/*
 * Get Authority and Subject Key Identifiers
 */
Tcl_Obj *Tls_x509Identifier(const ASN1_OCTET_STRING *astring) {
    Tcl_Obj *resultPtr = NULL;
    int len = 0;
    unsigned char buffer[1024];

    if (astring != NULL) {
	len = String_to_Hex((unsigned char *) ASN1_STRING_get0_data(astring),
	    ASN1_STRING_length(astring), buffer, 1024);
    }
    resultPtr = Tcl_NewStringObj((char *) &buffer[0], (Tcl_Size) len);
    return resultPtr;
}

/*
 * Get Key Usage
 */
Tcl_Obj *Tls_x509KeyUsage(Tcl_Interp *interp, X509 *cert, uint32_t xflags) {

    int len;
    char buffer[1024];

    if (listPtr == NULL) {
	return NULL;
    }

    if ((names = X509_get_ext_d2i(cert, nid, NULL, NULL)) != NULL) {
	for (int i=0; i < sk_GENERAL_NAME_num(names); i++) {
	    const GENERAL_NAME *name = sk_GENERAL_NAME_value(names, i);

	    len = BIO_to_Buffer(name && GENERAL_NAME_print(bio, (GENERAL_NAME *) name), bio, buffer, 1024);
	    LAPPEND_STR(interp, listPtr, NULL, buffer, (Tcl_Size) len);
	}
	sk_GENERAL_NAME_pop_free(names, GENERAL_NAME_free);
    }
    return listPtr;
}

    STACK_OF(DIST_POINT) *crl;
    Tcl_Obj *listPtr = Tcl_NewListObj(0, NULL);

    if (listPtr == NULL) {
	return NULL;
    }

    if ((crl = X509_get_ext_d2i(cert, NID_crl_distribution_points, NULL, NULL)) != NULL) {
	for (int i=0; i < sk_DIST_POINT_num(crl); i++) {
	    DIST_POINT *dp = sk_DIST_POINT_value(crl, i);
	    DIST_POINT_NAME *distpoint = dp->distpoint;

	    if (distpoint->type == 0) {
		/* full-name GENERALIZEDNAME */
		for (int j = 0; j < sk_GENERAL_NAME_num(distpoint->name.fullname); j++) {
		    GENERAL_NAME *gen = sk_GENERAL_NAME_value(distpoint->name.fullname, j);
		    int type;
		    ASN1_STRING *uri = GENERAL_NAME_get0_value(gen, &type);
		    if (type == GEN_URI) {
			LAPPEND_STR(interp, listPtr, (char *) NULL, (char *) ASN1_STRING_get0_data(uri), (Tcl_Size) ASN1_STRING_length(uri));
		    }
		}
	    } else if (distpoint->type == 1) {
		/* relative-name X509NAME */
		STACK_OF(X509_NAME_ENTRY) *sk_relname = distpoint->name.relativename;
		for (int j = 0; j < sk_X509_NAME_ENTRY_num(sk_relname); j++) {
		    X509_NAME_ENTRY *e = sk_X509_NAME_ENTRY_value(sk_relname, j);
		    ASN1_STRING *d = X509_NAME_ENTRY_get_data(e);
		    LAPPEND_STR(interp, listPtr, (char *) NULL, (char *) ASN1_STRING_data(d), (Tcl_Size) ASN1_STRING_length(d));
		}
	    }
	}
	CRL_DIST_POINTS_free(crl);
    }
    return listPtr;
}

/*
 * Get On-line Certificate Status Protocol (OSCP) URL
 */
Tcl_Obj *Tls_x509Oscp(Tcl_Interp *interp, X509 *cert) {
    STACK_OF(OPENSSL_STRING) *ocsp;
    Tcl_Obj *listPtr = Tcl_NewListObj(0, NULL);

    if (listPtr == NULL) {
	return NULL;
    }

    if ((ocsp = X509_get1_ocsp(cert)) != NULL) {
	for (int i = 0; i < sk_OPENSSL_STRING_num(ocsp); i++) {
	    LAPPEND_STR(interp, listPtr, NULL, sk_OPENSSL_STRING_value(ocsp, i), -1);
	}
	X509_email_free(ocsp);
    }
    return listPtr;
}

/*
 * Get Certificate Authority (CA) Issuers URL
 */
Tcl_Obj *Tls_x509CaIssuers(Tcl_Interp *interp, X509 *cert) {
    STACK_OF(ACCESS_DESCRIPTION) *ads;
    ACCESS_DESCRIPTION *ad;
    Tcl_Obj *listPtr = Tcl_NewListObj(0, NULL);
    unsigned char *buf;
    int len;

    if ((ads = X509_get_ext_d2i(cert, NID_info_access, NULL, NULL)) != NULL) {
	for (int i = 0; i < sk_ACCESS_DESCRIPTION_num(ads); i++) {
	    ad = sk_ACCESS_DESCRIPTION_value(ads, i);
	    if (OBJ_obj2nid(ad->method) == NID_ad_ca_issuers && ad->location) {
		if (ad->location->type == GEN_URI) {
		    len = ASN1_STRING_to_UTF8(&buf, ad->location->d.uniformResourceIdentifier);
		    Tcl_ListObjAppendElement(interp, listPtr, Tcl_NewStringObj((char *) buf, (Tcl_Size) len));
		    OPENSSL_free(buf);
		    break;
		}
	    }
	}
	/* sk_ACCESS_DESCRIPTION_pop_free(ads, ACCESS_DESCRIPTION_free); */
	AUTHORITY_INFO_ACCESS_free(ads);

 */

Tcl_Obj*
Tls_NewX509Obj(Tcl_Interp *interp, X509 *cert) {
    Tcl_Obj *certPtr = Tcl_NewListObj(0, NULL);
    BIO *bio = BIO_new(BIO_s_mem());
    int mdnid, pknid, bits, len;
    unsigned int ulen;
    uint32_t xflags;
    char buffer[BUFSIZ];
    unsigned char md[EVP_MAX_MD_SIZE];
    unsigned long flags = XN_FLAG_RFC2253 | ASN1_STRFLGS_UTF8_CONVERT;
    flags &= ~ASN1_STRFLGS_ESC_MSB;

    if (interp == NULL || cert == NULL || bio == NULL || certPtr == NULL) {

	const ASN1_BIT_STRING *sig;
	int sig_nid;

	X509_get0_signature(&sig, &sig_alg, cert);
	/* sig_nid = X509_get_signature_nid(cert) */
	sig_nid = OBJ_obj2nid(sig_alg->algorithm);
	LAPPEND_STR(interp, certPtr, "signatureAlgorithm", OBJ_nid2ln(sig_nid), -1);
	len = (sig_nid != NID_undef) ? String_to_Hex(sig->data, sig->length, (unsigned char *) buffer, BUFSIZ) : 0;
	LAPPEND_STR(interp, certPtr, "signatureValue", buffer, (Tcl_Size) len);
    }

    /* Version of the encoded certificate - RFC 5280 section 4.1.2.1 */
    LAPPEND_LONG(interp, certPtr, "version", X509_get_version(cert)+1);

    /* Unique number assigned by CA to certificate - RFC 5280 section 4.1.2.2 */

    /* Subject identifies the entity associated with the public key stored in
	the subject public key field. RFC 5280 section 4.1.2.6 */
    len = BIO_to_Buffer(X509_NAME_print_ex(bio, X509_get_subject_name(cert), 0, flags), bio, buffer, BUFSIZ);
    LAPPEND_STR(interp, certPtr, "subject", buffer, (Tcl_Size) len);

    /* SHA1 Digest (Fingerprint) of cert - DER representation */
    if (X509_digest(cert, EVP_sha1(), md, &ulen)) {
	len = String_to_Hex(md, len, (unsigned char *) buffer, BUFSIZ);
	LAPPEND_STR(interp, certPtr, "sha1_hash", buffer, (Tcl_Size) ulen);
    }

    /* SHA256 Digest (Fingerprint) of cert - DER representation */
    if (X509_digest(cert, EVP_sha256(), md, &ulen)) {
	len = String_to_Hex(md, len, (unsigned char *) buffer, BUFSIZ);
	LAPPEND_STR(interp, certPtr, "sha256_hash", buffer, (Tcl_Size) ulen);
    }

    /* Subject Public Key Info specifies the public key and identifies the
	algorithm with which the key is used. RFC 5280 section 4.1.2.7 */
    if (X509_get_signature_info(cert, &mdnid, &pknid, &bits, &xflags)) {
	ASN1_BIT_STRING *key;
	unsigned int n;

	LAPPEND_STR(interp, certPtr, "signingDigest", OBJ_nid2ln(mdnid), -1);
	LAPPEND_STR(interp, certPtr, "publicKeyAlgorithm", OBJ_nid2ln(pknid), -1);
	LAPPEND_INT(interp, certPtr, "bits", bits); /* Effective security bits */

	key = X509_get0_pubkey_bitstr(cert);
	len = String_to_Hex(key->data, key->length, (unsigned char *) buffer, BUFSIZ);
	LAPPEND_STR(interp, certPtr, "publicKey", buffer, (Tcl_Size) len);

	len = 0;
	if (X509_pubkey_digest(cert, EVP_get_digestbynid(pknid), md, &n)) {
	    len = String_to_Hex(md, (int) n, (unsigned char *) buffer, BUFSIZ);
	}
	LAPPEND_STR(interp, certPtr, "publicKeyHash", buffer, (Tcl_Size) len);

	/* digest of the DER representation of the certificate */
	len = 0;
	if (X509_digest(cert, EVP_get_digestbynid(mdnid), md, &n)) {
	    len = String_to_Hex(md, (int) n, (unsigned char *) buffer, BUFSIZ);
	}
	LAPPEND_STR(interp, certPtr, "signatureHash", buffer, (Tcl_Size) len);
    }

    /* Certificate Purpose. Call before checking for extensions. */
    LAPPEND_STR(interp, certPtr, "purpose", Tls_x509Purpose(cert), -1);
    LAPPEND_OBJ(interp, certPtr, "certificatePurpose", Tls_x509Purposes(interp, cert));

	and/or issuer names over time. RFC 5280 section 4.1.2.8 */
    {
	const ASN1_BIT_STRING *iuid, *suid;
	X509_get0_uids(cert, &iuid, &suid);

	Tcl_ListObjAppendElement(interp, certPtr, Tcl_NewStringObj("issuerUniqueId", -1));
	if (iuid != NULL) {
	    Tcl_ListObjAppendElement(interp, certPtr, Tcl_NewByteArrayObj((const unsigned char *)iuid->data, (Tcl_Size) iuid->length));
	} else {
	    Tcl_ListObjAppendElement(interp, certPtr, Tcl_NewStringObj("", -1));
	}

	Tcl_ListObjAppendElement(interp, certPtr, Tcl_NewStringObj("subjectUniqueId", -1));
	if (suid != NULL) {
	    Tcl_ListObjAppendElement(interp, certPtr, Tcl_NewByteArrayObj((const unsigned char *)suid->data, (Tcl_Size) suid->length));
	} else {
	    Tcl_ListObjAppendElement(interp, certPtr, Tcl_NewStringObj("", -1));
	}
    }

    /* X509 v3 Extensions - RFC 5280 section 4.1.2.9 */
    LAPPEND_INT(interp, certPtr, "extCount", X509_get_ext_count(cert));

    /* Subject Information Access - RFC 5280 section 4.2.2.2, NID_sinfo_access */

    /* Certificate Alias. If uses a PKCS#12 structure, alias will reflect the
	friendlyName attribute (RFC 2985). */
    {
	len = 0;
        unsigned char *string = X509_alias_get0(cert, &len);
	LAPPEND_STR(interp, certPtr, "alias", (char *) string, (Tcl_Size) len);
	string = X509_keyid_get0 (cert, &len);
	LAPPEND_STR(interp, certPtr, "keyId", (char *) string, (Tcl_Size) len);
    }

    /* Certificate and dump all data */
    {
	char certStr[CERT_STR_SIZE];

	/* Get certificate */