關於 OpenSSL 的介紹及安裝請參見：Windows 下編譯 OpenSSL
下面主要介紹有關 OpenSSL 使用 base64 編碼/解碼。
編碼/解碼
#include <openssl/evp.h> #include <openssl/bio.h> #include <openssl/buffer.h> #include <string> #include <iostream> using namespace std; char * base64Encode(const char *buffer, int length, bool newLine); char * base64Decode(char *input, int length, bool newLine); int main(int argc, char* argv[]) { bool newLine = false; string input = "Hello World!"; char * encode = base64Encode(input.c_str(), input.length(), newLine); char * decode = base64Decode(encode, strlen(encode), newLine); cout << "Base64 Encoded : " << encode << endl; cout << "Base64 Decoded : " << decode << endl; cin.get(); } // base64 編碼 char * base64Encode(const char *buffer, int length, bool newLine) { BIO *bmem = NULL; BIO *b64 = NULL; BUF_MEM *bptr; b64 = BIO_new(BIO_f_base64()); if (!newLine) { BIO_set_flags(b64, BIO_FLAGS_BASE64_NO_NL); } bmem = BIO_new(BIO_s_mem()); b64 = BIO_push(b64, bmem); BIO_write(b64, buffer, length); BIO_flush(b64); BIO_get_mem_ptr(b64, &bptr); BIO_set_close(b64, BIO_NOCLOSE); char *buff = (char *)malloc(bptr->length + 1); memcpy(buff, bptr->data, bptr->length); buff[bptr->length] = 0; BIO_free_all(b64); return buff; } // base64 解碼 char * base64Decode(char *input, int length, bool newLine) { BIO *b64 = NULL; BIO *bmem = NULL; char *buffer = (char *)malloc(length); memset(buffer, 0, length); b64 = BIO_new(BIO_f_base64()); if (!newLine) { BIO_set_flags(b64, BIO_FLAGS_BASE64_NO_NL); } bmem = BIO_new_mem_buf(input, length); bmem = BIO_push(b64, bmem); BIO_read(bmem, buffer, length); BIO_free_all(bmem); return buffer; }輸出如下所示：
Base64 Encoded : SGVsbG8gV29ybGQh
Base64 Decoded : Hello World!
更多參考
http://blog.csdn.net/liang19890820/article/details/52948306