1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis */
2 /* SPDX-License-Identifier: Unlicense */
3
4 #include "tomcrypt_private.h"
5
6 #ifdef LTC_BASE32
7
8 /**
9 Base32 decode a buffer
10 @param in The Base32 data to decode
11 @param inlen The length of the Base32 data
12 @param out [out] The destination of the binary decoded data
13 @param outlen [in/out] The max size and resulting size of the decoded data
14 @param id Alphabet to use BASE32_RFC4648, BASE32_BASE32HEX, BASE32_ZBASE32 or BASE32_CROCKFORD
15 @return CRYPT_OK if successful
16 */
base32_decode(const char * in,unsigned long inlen,unsigned char * out,unsigned long * outlen,base32_alphabet id)17 int base32_decode(const char *in, unsigned long inlen,
18 unsigned char *out, unsigned long *outlen,
19 base32_alphabet id)
20 {
21 unsigned long x;
22 int y = 0;
23 ulong64 t = 0;
24 char c;
25 const unsigned char *map;
26 const unsigned char tables[4][43] = {
27 { /* id = BASE32_RFC4648 : ABCDEFGHIJKLMNOPQRSTUVWXYZ234567 */
28 99/*0*/,99/*1*/,26/*2*/,27/*3*/,28/*4*/,29/*5*/,30/*6*/,31/*7*/,99/*8*/,99/*9*/,
29 99/*:*/,99/*;*/,99/*<*/,99/*=*/,99/*>*/,99/*?*/,99/*@*/,
30 0/*A*/, 1/*B*/, 2/*C*/, 3/*D*/, 4/*E*/, 5/*F*/, 6/*G*/, 7/*H*/, 8/*I*/, 9/*J*/,10/*K*/,11/*L*/,12/*M*/,
31 13/*N*/,14/*O*/,15/*P*/,16/*Q*/,17/*R*/,18/*S*/,19/*T*/,20/*U*/,21/*V*/,22/*W*/,23/*X*/,24/*Y*/,25/*Z*/
32 },
33 { /* id = BASE32_BASE32HEX : 0123456789ABCDEFGHIJKLMNOPQRSTUV */
34 0/*0*/, 1/*1*/, 2/*2*/, 3/*3*/, 4/*4*/, 5/*5*/, 6/*6*/, 7/*7*/, 8/*8*/, 9/*9*/,
35 99/*:*/,99/*;*/,99/*<*/,99/*=*/,99/*>*/,99/*?*/,99/*@*/,
36 10/*A*/,11/*B*/,12/*C*/,13/*D*/,14/*E*/,15/*F*/,16/*G*/,17/*H*/,18/*I*/,19/*J*/,20/*K*/,21/*L*/,22/*M*/,
37 23/*N*/,24/*O*/,25/*P*/,26/*Q*/,27/*R*/,28/*S*/,29/*T*/,30/*U*/,31/*V*/,99/*W*/,99/*X*/,99/*Y*/,99/*Z*/
38 },
39 { /* id = BASE32_ZBASE32 : YBNDRFG8EJKMCPQXOT1UWISZA345H769 */
40 99/*0*/,18/*1*/,99/*2*/,25/*3*/,26/*4*/,27/*5*/,30/*6*/,29/*7*/, 7/*8*/,31/*9*/,
41 99/*:*/,99/*;*/,99/*<*/,99/*=*/,99/*>*/,99/*?*/,99/*@*/,
42 24/*A*/, 1/*B*/,12/*C*/, 3/*D*/, 8/*E*/, 5/*F*/, 6/*G*/,28/*H*/,21/*I*/, 9/*J*/,10/*K*/,99/*L*/,11/*M*/,
43 2/*N*/,16/*O*/,13/*P*/,14/*Q*/, 4/*R*/,22/*S*/,17/*T*/,19/*U*/,99/*V*/,20/*W*/,15/*X*/, 0/*Y*/,23/*Z*/
44 },
45 { /* id = BASE32_CROCKFORD : 0123456789ABCDEFGHJKMNPQRSTVWXYZ + O=>0 + IL=>1 */
46 0/*0*/, 1/*1*/, 2/*2*/, 3/*3*/, 4/*4*/, 5/*5*/, 6/*6*/, 7/*7*/, 8/*8*/, 9/*9*/,
47 99/*:*/,99/*;*/,99/*<*/,99/*=*/,99/*>*/,99/*?*/,99/*@*/,
48 10/*A*/,11/*B*/,12/*C*/,13/*D*/,14/*E*/,15/*F*/,16/*G*/,17/*H*/, 1/*I*/,18/*J*/,19/*K*/, 1/*L*/,20/*M*/,
49 21/*N*/, 0/*O*/,22/*P*/,23/*Q*/,24/*R*/,25/*S*/,26/*T*/,99/*U*/,27/*V*/,28/*W*/,29/*X*/,30/*Y*/,31/*Z*/
50 }
51 };
52
53 LTC_ARGCHK(in != NULL);
54 LTC_ARGCHK(out != NULL);
55 LTC_ARGCHK(outlen != NULL);
56 LTC_ARGCHK(id >= BASE32_RFC4648);
57 LTC_ARGCHK(id <= BASE32_CROCKFORD);
58
59 /* ignore all trailing = */
60 while (inlen > 0 && in[inlen-1] == '=') inlen--;
61
62 /* no input, nothing to do */
63 if (inlen == 0) {
64 *outlen = 0;
65 return CRYPT_OK;
66 }
67
68 /* check the size of output buffer */
69 x = (inlen * 5) / 8;
70 if (*outlen < x) {
71 *outlen = x;
72 return CRYPT_BUFFER_OVERFLOW;
73 }
74 *outlen = x;
75
76 /* check input data length */
77 x = inlen % 8;
78 if (x == 1 || x == 3 || x == 6) {
79 return CRYPT_INVALID_PACKET;
80 }
81
82 map = tables[id];
83 for (x = 0; x < inlen; x++) {
84 c = in[x];
85 /* convert to upper case */
86 if ((c >= 'a') && (c <= 'z')) c -= 32;
87 if (c < '0' || c > 'Z' || map[c-'0'] > 31) {
88 return CRYPT_INVALID_PACKET;
89 }
90 t = (t<<5) | map[c-'0'];
91 if (++y == 8) {
92 *out++ = (unsigned char)((t>>32) & 255);
93 *out++ = (unsigned char)((t>>24) & 255);
94 *out++ = (unsigned char)((t>>16) & 255);
95 *out++ = (unsigned char)((t>> 8) & 255);
96 *out++ = (unsigned char)( t & 255);
97 y = 0;
98 t = 0;
99 }
100 }
101 if (y > 0) {
102 t = t << (5 * (8 - y));
103 if (y >= 2) *out++ = (unsigned char)((t>>32) & 255);
104 if (y >= 4) *out++ = (unsigned char)((t>>24) & 255);
105 if (y >= 5) *out++ = (unsigned char)((t>>16) & 255);
106 if (y >= 7) *out++ = (unsigned char)((t>> 8) & 255);
107 }
108 return CRYPT_OK;
109 }
110
111 #endif
112