Howto base64 encode with C/C++ and OpenSSL

I’ve been doing a little C programming lately and I have found that if you have a up to date distribution of linux there are a lot of libraries out there that make doing things you do in other languages like java easier.

As I have time I’m going to post some examples of what I have found. The first here is how to base64 encode a chunk of memory using OpenSLL.

#include <string.h>

#include <openssl/sha.h>
#include <openssl/hmac.h>
#include <openssl/evp.h>
#include <openssl/bio.h>
#include <openssl/buffer.h>

char *base64(const unsigned char *input, int length);

int main(int argc, char **argv)
{
  char *output = base64("YOYO!", sizeof("YOYO!"));
  printf("Base64: *%s*\\n", output);
  free(output);
}

char *base64(const unsigned char *input, int length)
{
  BIO *bmem, *b64;
  BUF_MEM *bptr;

  b64 = BIO_new(BIO_f_base64());
  bmem = BIO_new(BIO_s_mem());
  b64 = BIO_push(b64, bmem);
  BIO_write(b64, input, length);
  BIO_flush(b64);
  BIO_get_mem_ptr(b64, &bptr);

  char *buff = (char *)malloc(bptr->length);
  memcpy(buff, bptr->data, bptr->length-1);
  buff[bptr->length-1] = 0;

  BIO_free_all(b64);

  return buff;
}

And to compile this just use the following command:

cc -o base64 base64.c -lssl
del.icio.us:Howto base64 encode with C/C++ and OpenSSL digg:Howto base64 encode with C/C++ and OpenSSL spurl:Howto base64 encode with C/C++ and OpenSSL wists:Howto base64 encode with C/C++ and OpenSSL simpy:Howto base64 encode with C/C++ and OpenSSL newsvine:Howto base64 encode with C/C++ and OpenSSL blinklist:Howto base64 encode with C/C++ and OpenSSL furl:Howto base64 encode with C/C++ and OpenSSL reddit:Howto base64 encode with C/C++ and OpenSSL fark:Howto base64 encode with C/C++ and OpenSSL blogmarks:Howto base64 encode with C/C++ and OpenSSL Y!:Howto base64 encode with C/C++ and OpenSSL smarking:Howto base64 encode with C/C++ and OpenSSL magnolia:Howto base64 encode with C/C++ and OpenSSL segnalo:Howto base64 encode with C/C++ and OpenSSL gifttagging:Howto base64 encode with C/C++ and OpenSSL

This entry was posted on Tuesday, April 11th, 2006 at 11:26 am by carsonm and is filed under C/C++. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

One Response to “Howto base64 encode with C/C++ and OpenSSL”

  1. bsm Says:
    November 30th, 2006 at 10:24 pm

    I found this works better, as some chars were being chopped off during subsequent decoding:

    char *buff = (char *)malloc(bptr->length+1);
    memcpy(buff, bptr->data, bptr->length);
    buff[bptr->length] = 0;

Leave a Reply