做base64编码和解码的OpenSSL C ++ [英] Doing base64 encoding and decoding in OpenSSL C++

问题描述

我一直尝试了一段时间，现在要弄清楚的base64进行解码和编码的OpenSSL文档。我发现在网络上的一些code片段下方

Ive been trying for some time now to figure out the openssl documentation for base64 decoding and encoding. I found some code snippets on the net below

 #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)
{
  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;
}

char *decode64(unsigned char *input, int length)
{
  BIO *b64, *bmem;

  char *buffer = (char *)malloc(length);
  memset(buffer, 0, length);

  b64 = BIO_new(BIO_f_base64());
  bmem = BIO_new_mem_buf(input, length);
  bmem = BIO_push(b64, bmem);

  BIO_read(bmem, buffer, length);

  BIO_free_all(bmem);

  return buffer;
}

这似乎只为单行字符串，例如开始，笔者为大家介绍用换行和空格等复杂的字符串目前它可怕的失败工作。我似乎无法找到任何文件或完整code的例子来做到这一点，因为它很紧迫，我想我会问，如果有人可以帮助。

This only seems to work for single line strings such as "Start", the moment I introduce complex strings with newlines and spaces etc it fails horribly. I cant seem to find any documentation or complete code example to do this and as its quite urgent I thought I would ask if anyone could help.

它不甚至是OpenSSL的，一个简单的类或一组做同样的事情会被罚款的功能，那里有一个非常复杂的构建过程的解决方案，我想以避免去那里进行多次变化。我去的OpenSSL的唯一原因是因为该解决方案已经与库编译

It doesnt even have to be openssl, a simple class or set of functions that do the same thing would be fine, theres a very complicated build process for the solution and I am trying to avoid having to go in there and make multiple changes. The only reason I went for openssl is because the solution is already compiled with the libraries

欢呼声

推荐答案

就个人而言，我觉得OpenSSL的API是如此令人难以置信的痛苦的使用，我尽量避免它，除非它回避的成本是非常高的。我觉得很不安，它已成为世界上加密的标准API。

Personally, I find the OpenSSL API to be so incredibly painful to use, I avoid it unless the cost of avoiding it is extremely high. I find it quite upsetting that it has become the standard API in the crypto world.

我感到无聊，而我写你一在C ++中。这其中甚至应该处理的边缘情况，可能会导致安全问题，等等，例如，编码导致整数溢出，因为它太大的字符串。

I was feeling bored, and I wrote you one in C++. This one should even handle the edge cases that can cause security problems, like, for example, encoding a string that results in integer overflow because it's too large.

我已经做了一些关于它的单元测试，所以它应该工作。

I have done some unit testing on it, so it should work.

#include <string>
#include <cassert>
#include <limits>
#include <stdexcept>
#include <cctype>

static const char b64_table[65] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

static const char reverse_table[128] = {
   64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
   64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
   64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 62, 64, 64, 64, 63,
   52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 64, 64, 64, 64, 64, 64,
   64,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
   15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 64, 64, 64, 64, 64,
   64, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
   41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 64, 64, 64, 64, 64
};

::std::string base64_encode(const ::std::string &bindata)
{
   using ::std::string;
   using ::std::numeric_limits;

   if (bindata.size() > (numeric_limits<string::size_type>::max() / 4u) * 3u) {
      throw ::std::length_error("Converting too large a string to base64.");
   }

   const ::std::size_t binlen = bindata.size();
   // Use = signs so the end is properly padded.
   string retval((((binlen + 2) / 3) * 4), '=');
   ::std::size_t outpos = 0;
   int bits_collected = 0;
   unsigned int accumulator = 0;
   const string::const_iterator binend = bindata.end();

   for (string::const_iterator i = bindata.begin(); i != binend; ++i) {
      accumulator = (accumulator << 8) | (*i & 0xffu);
      bits_collected += 8;
      while (bits_collected >= 6) {
         bits_collected -= 6;
         retval[outpos++] = b64_table[(accumulator >> bits_collected) & 0x3fu];
      }
   }
   if (bits_collected > 0) { // Any trailing bits that are missing.
      assert(bits_collected < 6);
      accumulator <<= 6 - bits_collected;
      retval[outpos++] = b64_table[accumulator & 0x3fu];
   }
   assert(outpos >= (retval.size() - 2));
   assert(outpos <= retval.size());
   return retval;
}

::std::string base64_decode(const ::std::string &ascdata)
{
   using ::std::string;
   string retval;
   const string::const_iterator last = ascdata.end();
   int bits_collected = 0;
   unsigned int accumulator = 0;

   for (string::const_iterator i = ascdata.begin(); i != last; ++i) {
      const int c = *i;
      if (::std::isspace(c) || c == '=') {
         // Skip whitespace and padding. Be liberal in what you accept.
         continue;
      }
      if ((c > 127) || (c < 0) || (reverse_table[c] > 63)) {
         throw ::std::invalid_argument("This contains characters not legal in a base64 encoded string.");
      }
      accumulator = (accumulator << 6) | reverse_table[c];
      bits_collected += 6;
      if (bits_collected >= 8) {
         bits_collected -= 8;
         retval += (char)((accumulator >> bits_collected) & 0xffu);
      }
   }
   return retval;
}

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