A cross-platform C11 library which depends on OpenSSL that allows to easily and quickly add crypto capabilities to your projects.

Its main purpose is to be the crypto module of LibUnknownEcho library.

The goal is NOT to wrap all features of Openssl, but only the most widely used features.

Features

• data encryption

  • using symmetric encryption
  • using asymmetric encryption
  • using both asynmmetric and symmetric encryption for large data

• file encryption

  • using symmetric encryption

• certificate management

  • x509 certificate generation
  • x509 certificate signing
  • x509 certificate signing request (CSR)

• hashing

• pkcs12 keystore

• signing

• crypto random

• encoding

  • base64 encoding

• compression

Installation

Clone the repository:

git clone http://github.com/swasun/LibUnknownEchoUtilsModule

Build in release mode:

mkdir -p build/release
cmake -Bbuild/release -H. -DCMAKE_BUILD_TYPE=Release
cd build/release
cmake --build . --config Release

Or build in debug mode:

mkdir -p build/debug
cmake -Bbuild/debug -H. -DCMAKE_BUILD_TYPE=Debug
cd build/debug
cmake --build . --config Debug

• By default, dependencies are built and install in the build directoy. To specify an other path, add -DLIBEI_INSTALL=/usr flag (LIBUEUM_INSTALL for LIBUEUM) in cmake command.

• To build with LIBEI already installed in the system, add -DLIBEI_SYSTEM=TRUE flag in cmake command.

• To build with LIBUEUM already installed in the system, add -DLIBUEUM_SYSTEM=TRUE flag in cmake command.

• Alternatively, you can build using build_release.<sh|bat> and build_debug.<sh|bat> scripts.

Finally, to install in the system:

cd build/release
<sudo> cmake --build . --config Release --target install

Examples

Some examples are available in examples directory.

./bin/release/examples/progress_bar_example

Basic usage

The following basic_usage.c is an example of a simple usage of the library (for the sake of clarity, error handling are omitted here, but complete example file is availabe in ̀examples directory):

#include <uecm/uecm.h> /* Include LibUnknownEchoCryptoModule */
#include <ueum/ueum.h> /* Include LibUnknownEchoUtilsModule */
#include <ei/ei.h> /* Include LibErrorInterceptor */

#include <stddef.h>
#include <string.h>

int main(int argc, char **argv) {
    unsigned char *plain_data, *cipher_data, *decipher_data;
    size_t plain_data_size, cipher_data_size, decipher_data_size;
    uecm_asym_key *key;
    int key_size;

    ei_init_or_die(); /* Initialize LibErrorInterceptor */

    uecm_init_or_die();  /* Initialize LibUnknownEchoCryptoModule */

    /* Use LibUnknownEchoCryptoModule */

    plain_data = NULL;
    cipher_data = NULL;
    decipher_data = NULL;
    key_size = 4096;

    /* Convert the string input in bytes */
    plain_data = ueum_bytes_create_from_string(argv[1]);
    plain_data_size = strlen(argv[1]);

    /* Generate a random RSA key pair */
    key = uecm_rsa_asym_key_create(key_size);
    
    /**
     * Cipher plain data using both asymmetric (4096-RSA) and
     * symmetric encryption (AES-256-CBC), compression
     * (inflate/deflate of zlib), signing (SHA-256).
     * The private key parameter (key->sk) is optional,
     * and used to sign the cipher data.
     */ 
    uecm_cipher_plain_data(plain_data, plain_data_size, key->pk, key->sk, &cipher_data, &cipher_data_size, "aes-256-cbc", "sha256");

    /**
     * Decipher cipher data using both asymmetric (4096-RSA) and
     * symmetric encryption (AES-256-CBC), compression
     * (inflate/deflate of zlib), signing (SHA-256).
     * The public key parameter (key->pk) is optional,
     * and used to verify the signature of the cipher data.
     */
    uecm_decipher_cipher_data(cipher_data, cipher_data_size, key->sk, key->pk, &decipher_data, &decipher_data_size,
        "aes-256-cbc", "sha256");

    /* Check if decipher data and plain data are equals */
    ei_logger_info("Comparing decipher data with plain data...");
    if (plain_data_size == decipher_data_size && memcmp(decipher_data, plain_data, plain_data_size) == 0) {
        ei_logger_info("Plain data and decipher data match");
    } else {
        ei_logger_error("Plain data and decipher data doesn't match");
    }

clean_up:
    /* Clean_up variables */
    ueum_safe_free(plain_data);
    ueum_safe_free(cipher_data);
    ueum_safe_free(decipher_data);
    uecm_asym_key_destroy_all(key);

    /**
     * Each time ei_stacktrace API is used in libueum or libuecm,
     * an error is record to the stacktrace of the current thread.
     */
    if (ei_stacktrace_is_filled()) {
        ei_logger_error("Error(s) occurred with the following stacktrace(s):");
        ei_stacktrace_print_all();
    }

    uecm_uninit(); /* uninitialize LibUnknownEchoCryptoModule */

    ei_uninit(); /* uninitialize LibErrorInterceptor */

    return 0;
}

Compile statically:

gcc -o basic_usage examples/basic_usage.c -lei_static -luecm_static -lueum_static -pthread lib/openssl/lib/libssl.a lib/openssl/lib/libcrypto.a lib/zlib/lib/libz.a -ldl

Run:

./basic_usage "Hello world !"

note: -pthread and -ldl flags are necessary for Unix systems.

Dependencies

• LibErrorInterceptor, a lightweight and cross-plateform library to handle stacktrace and logging in C99.
• LibUnknownEchoUtilsModule Utils module of LibUnknownEcho. Last version
• Openssl provides general cryptographic and X.509 support needed by SSL/TLS but not logically part of it. Version 1.1.0.
• Zlib A massively spiffy yet delicately unobtrusive compression library. Version 1.2.11.

Architecture

Facade design pattern

The facade design pattern is use to simplify the complexity of a module. In the module, we have 2 to 4 sub folders which are:

• api: that contains the highest level of functions/structs of the module.
• impl: that contains implementation(s) a api files.
• factory (optional): that contains factories to create complex objects from the api files.
• utils (optional): that contains utils functions only used in this module.

Cross-plateform

Successfully tested on the following OS (on 64 bits):

• Ubuntu 14.04
• Ubuntu 16.04
• Windows 10