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Today, I will talk to you about the encryption and decryption of base64 based on openssl, which may not be well understood by many people. in order to make you understand better, the editor has summarized the following contents for you. I hope you can get something according to this article.

1. What is base64?

Base64 refers to 64 printable characters, including "Amurz", "aquiz", "0per9", "+" and "/". Base64 is generally used to represent binary data (every byte of a binary stream cannot be all visible characters, so it cannot be transmitted, it can be transferred after base64 conversion).

two。 Use openssl's library to encapsulate base64's encryption and decryption library

Use dynamic memory allocation

/ * @ Filename: base64_1_by_openssl.c* @ Author:edwin* @ Description:-* @ Create: 2020-12-21 10 Author:edwin* 1914 20 * @ Last Modified: 2020-12-21 10 purl 31 Frey 39 * * * / # include # include "openssl/evp.h" # include "openssl/bio.h" # include "openssl/buffer.h" char * base64_encode (const char * input Int length, bool newLine) Char* base64_decode (const char* input, int length, bool newLine,int * outLength); int main (int argc, char* argv []) {bool newLine = false; char input [64] = "test string"; int outlength; char* encode = base64_encode (input, strlen (input), newLine); char* decode = base64_decode (encode, strlen (encode), newLine,&outlength); printf ("base64 encode:%s\ n", encode) Printf ("base64 decode:%s\ n output length:%d\ n", decode,outlength); free (encode); free (decode); return 0;} / / base64 encoding. The output length is the length of a string. If necessary, you can use strlen to obtain char * base64_encode (const char * input, 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, input, 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); buffs [bptr-> length] ='\ 0mm; BIO_free_all (b64); return buff;} / / base64 Decoding char * base64_decode (const char * input, int length, bool newLine,int * outLength) {BIO * b64 = NULL; BIO * bmem = NULL Char * buffer = (char *) malloc (length); if (buffer = = NULL) {return NULL;} 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) * outLength = BIO_read (bmem, buffer, length); BIO_free_all (bmem); return buffer;}

two。 Using arrays, the messages are relatively stable, thus reducing system overhead (although it may be trivial)

/ * @ Filename: base64_2_by_openssl.c* @ Author:edwin* @ Description:-* @ Create: 2020-12-21 10 Author:edwin* 1912 * @ Last Modified: 2020-12-21 11 Suzhou 331* * * / # include # include "openssl/evp.h" # include "openssl/bio.h" # include "openssl/buffer.h" char * base64_encode (const char * input Int inputLength, bool newLine,char * output,int outputMaxLength) Char* base64_decode (const char* input, int inputLength, bool newLine,char * output,int outputMaxLength,int * outLength); int main (int argc, char* argv []) {bool newLine = false; char input [64] = "Hello Worldbuili\ nsddsdds"; char output [64]; char* encode = base64_encode (input, strlen (input), newLine,output,64); printf ("base64 encode:%s\ n", encode); int outlength=0 Char * decode = base64_decode (encode, strlen (encode), newLine,output,64,&outlength); printf ("base64 decode:%s\ nscene output length:%d\ n", output,outlength); return 0;} / / base64 Encoding char * base64_encode (const char * input, int inputLength, bool newLine,char * output,int outputMaxLength) {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, input, inputLength); BIO_flush (b64); BIO_get_mem_ptr (b64, & bptr); BIO_set_close (b64, BIO_NOCLOSE) If (bptr- > length > = outputMaxLength) {BIO_free_all (b64); return NULL;} memcpy (output, bptr- > data, bptr- > length); output [bptr-> length] ='\ 0mm; BIO_free_all (b64); return output } / / base64 decoding, the size of the output array should be larger than the input string size to ensure sufficient space char * base64_decode (const char * input, int inputLength, bool newLine,char * output,int outputMaxLength,int * outLength) {BIO * b64 = NULL; BIO * bmem = NULL; b64 = BIO_new (BIO_f_base64 ()); if (! newLine) {BIO_set_flags (b64, BIO_FLAGS_BASE64_NO_NL) } bmem = BIO_new_mem_buf (input, inputLength); bmem = BIO_push (b64, bmem); * outLength = BIO_read (bmem, output, inputLength); if (* outLength > = outputMaxLength) {BIO_free_all (bmem); return NULL;} output [* outLength] ='\ 0mm; BIO_free_all (bmem); return output;}

After reading the above, do you have any further understanding of base64 encryption and decryption based on openssl? If you want to know more knowledge or related content, please follow the industry information channel, thank you for your support.

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