Base64 encoding (C language Implementation)

base64-Wikipedia

Online Encryption and Decryption tool

#include <stdio.h> #include <stdint.h> #include <string.h> #include <malloc.h>char base64_ Table[] = {' A ', ' B ', ' C ', ' D ', ' E ', ' F ', ' G ', ' H ', ' I ', ' J ', ' K ', ' L ', ' M ', ' N ', ' O ', ' P ', ' Q ', ' R ', ' S ', ' T ', ' U ', ' V ', ' W ', ' X ', ' Y ', ' Z ', ' A ', ' B ', ' C ', ' d ', ' e ', ' f ', ' g ', ' h ', ' I ', ' j ', ' K ', ' l ', ' m ', ' n ', ' o ', ' P ', ' Q ', ' R ', ' s ', ' t ', ' u ', ' V ', ' w ', ' x ', ' Y '  , ' z ', ' 0 ', ' 1 ', ' 2 ', ' 3 ', ' 4 ', ' 5 ', ' 6 ', ' 7 ', ' 8 ', ' 9 ', ' + ', '-', ' + '};void base64_map (uint8_t *in_block, int len) {for (int i = 0; i < Len;        ++i) {In_block[i] = base64_table[in_block[i]];    printf ("%d%c", In_block[i], base64_table[in_block[i]);    } if (len% 4 = = 3) In_block[len] = ' = ';    else if (len% 4 = = 2) In_block[len] = in_block[len+1] = ' = '; return;}    void Base64_unmap (char *in_block) {int i;    Char *c;        for (int i = 0; i < 4; ++i) {c = in_block + i;            if (*c>= ' a ' && *c<= ' Z ') {*c-= ' a ';        Continue } if (*c>= ' a ' && *c<= ' Z ') {*c-= ' a ';            *c + = 26;        Continue            } if (*c = = ' + ') {*c = 62;        Continue            } if (*c = = '/') {*c = 63;        Continue            } if (*c = = ') {*c = 0;        Continue        } *c-= ' 0 ';    *c + = 52;    }}int Base64_encode (char *in, int inlen, uint8_t *out) {char *in_block;    uint8_t *out_block;    Char temp[3];    Out_block = out;    In_block = in;        for (int i = 0; i < inlen; i + = 3) {memset (temp, 0, 3);        memcpy (temp, In_block, i + 3 < Inlen 3:inlen-i);        memset (Out_block, 0, 4);        Out_block[0] = (Temp[0] >> 2) & 0x3f; OUT_BLOCK[1] = ((Temp[0] << 4) & 0x30) |        ((Temp[1] >> 4) & 0x0f); OUT_BLOCK[2] = ((Temp[1] << 2) & 0x3c) |        ((Temp[2] >> 6) & 0x03);        OUT_BLOCK[3] = (temp[2]) & 0x3f; printf ("%.2x%.2x%.2x\n", temp[0], temp[1], temp[2]);        printf ("%.2x%.2x%.2x%.2x\n", out_block[0], out_block[1], out_block[2], out_block[3]);        Out_block + = 4;    In_block + = 3; } Base64_map (Out, ((Inlen * 4)-1)/3 + 1);}    int Base64_decode (char *in, int inlen, uint8_t *out) {char *in_block;    uint8_t *out_block;    Char temp[4];    Out_block = out;    In_block = in;        for (int i = 0; i < inlen; i + = 4) {if (*in_block = = ' = ') return 0;        memcpy (temp, in_block, 4);        memset (Out_block, 0, 3);        Base64_unmap (temp); Out_block[0] = ((temp[0]<<2) & 0XFC) |        ((temp[1]>>4) & 3); OUT_BLOCK[1] = ((temp[1]<<4) & 0xf0) |        ((temp[2]>>2) & 0xf); OUT_BLOCK[2] = ((temp[2]<<6) & 0xc0) |        ((Temp[3]) & 0x3f);        Out_block + = 3;    In_block +=4; } return 0;}    int main () {char cipher_text[64];        while (scanf ("%s", cipher_text)! = EOF) {printf ("%s\n", Cipher_text); uint8_t *traN_cipher = (uint8_t *) malloc (sizeof (uint8_t) * 64);        memset (tran_cipher, 0, sizeof (uint8_t) * 64);        #define ENCODE #define DECODE #ifdef ENCODE printf ("----------------ENCODE-----------------");        Base64_encode (Cipher_text, strlen (Cipher_text), tran_cipher);        int len = (strlen (cipher_text) * 4-1)/3 + 1; Len = len% 4 = = 3?        Len + 1:len + 2;        for (int i = 0; i < len; ++i) printf ("%c", Tran_cipher[i]);        printf ("\ n");        #endif//ENCODE #ifdef DECODE printf ("----------------DECODE-----------------");        Base64_decode (Cipher_text, strlen (Cipher_text), tran_cipher);        Len = strlen (Cipher_text);        int n = len;        while (cipher_text[--n] = = ');        if (n = = len-2) len = (len >> 2) * 3-1;        else if (n = = len-3) len = (len >> 2) * 3-2;        else if (n = = len-1) len = (len >> 2) * 3; for (int i = 0; i < Len;        ++i) printf ("%c", Tran_cipher[i]);        printf ("\ n"); #endif//DECODE} return 0;}

　　

Base64 encoding (C language Implementation)