Couchbase C Client  2.10.6
Asynchronous C Client for Couchbase
example/crypto/openssl_symmetric_decrypt.c

Shows how to use field-encryption API to decrypt JSON values.

/* -*- Mode: C; tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/*
* Copyright 2018 Couchbase, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h> /* strlen */
#ifdef _WIN32
#define PRIx64 "I64x"
#else
#include <inttypes.h>
#endif
#include "openssl_symmetric_provider.h"
static void die(lcb_t instance, const char *msg, lcb_error_t err)
{
fprintf(stderr, "%s. Received code 0x%X (%s)\n", msg, err, lcb_strerror(instance, err));
exit(EXIT_FAILURE);
}
static void op_callback(lcb_t instance, int cbtype, const lcb_RESPBASE *rb)
{
if (rb->rc == LCB_SUCCESS) {
const lcb_RESPGET *rg = (const lcb_RESPGET *)rb;
lcbcrypto_FIELDSPEC field = {};
printf("VALUE: %.*s\n", (int)rg->nvalue, rg->value);
dcmd.version = 0;
dcmd.prefix = NULL;
dcmd.doc = rg->value;
dcmd.ndoc = rg->nvalue;
dcmd.out = NULL;
dcmd.nout = 0;
dcmd.nfields = 1;
dcmd.fields = &field;
field.name = "message";
field.alg = "AES-256-HMAC-SHA256";
err = lcbcrypto_decrypt_fields(instance, &dcmd);
if (err != LCB_SUCCESS) {
die(instance, "Couldn't decrypt field 'message'", err);
}
if (dcmd.out == NULL) {
die(instance, "Crypto provider returned success, but document is NULL", LCB_EINVAL);
}
/* chop trailing LF for nicer look */
if (dcmd.out[dcmd.nout - 1] == '\n') {
dcmd.out[dcmd.nout - 1] = ' ';
}
printf("PLAIN: %.*s\n", (int)dcmd.nout, dcmd.out);
free(dcmd.out); // NOTE: it should be compatible with what providers use to allocate memory
printf("CAS: 0x%" PRIx64 "\n", rb->cas);
} else {
die(instance, lcb_strcbtype(cbtype), rb->rc);
}
}
static void get_encrypted(lcb_t instance, const char *key)
{
lcb_CMDGET cmd = {};
LCB_CMD_SET_KEY(&cmd, key, strlen(key));
printf("KEY: %s\n", key);
err = lcb_get3(instance, NULL, &cmd);
if (err != LCB_SUCCESS) {
die(instance, "Couldn't schedule get operation", err);
}
lcb_wait(instance);
}
int main(int argc, char *argv[])
{
lcb_t instance;
{
struct lcb_create_st create_options = {};
create_options.version = 3;
if (argc < 2) {
fprintf(stderr, "Usage: %s couchbase://host/bucket [ password [ username ] ]\n", argv[0]);
exit(EXIT_FAILURE);
}
create_options.v.v3.connstr = argv[1];
if (argc > 2) {
create_options.v.v3.passwd = argv[2];
}
if (argc > 3) {
create_options.v.v3.username = argv[3];
}
err = lcb_create(&instance, &create_options);
if (err != LCB_SUCCESS) {
die(NULL, "Couldn't create couchbase handle", err);
}
err = lcb_connect(instance);
if (err != LCB_SUCCESS) {
die(instance, "Couldn't schedule connection", err);
}
lcb_wait(instance);
err = lcb_get_bootstrap_status(instance);
if (err != LCB_SUCCESS) {
die(instance, "Couldn't bootstrap from cluster", err);
}
lcb_install_callback3(instance, LCB_CALLBACK_GET, op_callback);
}
lcbcrypto_register(instance, "AES-256-HMAC-SHA256", osp_create());
get_encrypted(instance, "secret-1");
printf("\n");
get_encrypted(instance, "secret-2");
printf("\n");
get_encrypted(instance, "secret-3");
printf("\n");
get_encrypted(instance, "secret-4");
printf("\n");
get_encrypted(instance, "secret-5");
lcb_destroy(instance);
return 0;
}