1 // SPDX-License-Identifier: BSD-2-Clause
2 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
3 *
4 * LibTomCrypt is a library that provides various cryptographic
5 * algorithms in a highly modular and flexible manner.
6 *
7 * The library is free for all purposes without any express
8 * guarantee it works.
9 */
10 #include "tomcrypt_private.h"
11
12 /**
13 @file base64_encode.c
14 Compliant base64 encoder donated by Wayne Scott (wscott@bitmover.com)
15 base64 URL Safe variant (RFC 4648 section 5) by Karel Miko
16 */
17
18
19 #if defined(LTC_BASE64) || defined (LTC_BASE64_URL)
20
21 #if defined(LTC_BASE64)
22 static const char * const codes_base64 =
23 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
24 #endif /* LTC_BASE64 */
25
26 #if defined(LTC_BASE64_URL)
27 static const char * const codes_base64url =
28 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
29 #endif /* LTC_BASE64_URL */
30
_base64_encode_internal(const unsigned char * in,unsigned long inlen,char * out,unsigned long * outlen,const char * codes,int pad)31 static int _base64_encode_internal(const unsigned char *in, unsigned long inlen,
32 char *out, unsigned long *outlen,
33 const char *codes, int pad)
34 {
35 unsigned long i, len2, leven;
36 char *p;
37
38 LTC_ARGCHK(in != NULL);
39 LTC_ARGCHK(out != NULL);
40 LTC_ARGCHK(outlen != NULL);
41
42 /* valid output size ? */
43 len2 = 4 * ((inlen + 2) / 3);
44 if (*outlen < len2 + 1) {
45 *outlen = len2 + 1;
46 return CRYPT_BUFFER_OVERFLOW;
47 }
48 p = out;
49 leven = 3*(inlen / 3);
50 for (i = 0; i < leven; i += 3) {
51 *p++ = codes[(in[0] >> 2) & 0x3F];
52 *p++ = codes[(((in[0] & 3) << 4) + (in[1] >> 4)) & 0x3F];
53 *p++ = codes[(((in[1] & 0xf) << 2) + (in[2] >> 6)) & 0x3F];
54 *p++ = codes[in[2] & 0x3F];
55 in += 3;
56 }
57 /* Pad it if necessary... */
58 if (i < inlen) {
59 unsigned a = in[0];
60 unsigned b = (i+1 < inlen) ? in[1] : 0;
61
62 *p++ = codes[(a >> 2) & 0x3F];
63 *p++ = codes[(((a & 3) << 4) + (b >> 4)) & 0x3F];
64 if (pad) {
65 *p++ = (i+1 < inlen) ? codes[(((b & 0xf) << 2)) & 0x3F] : '=';
66 *p++ = '=';
67 }
68 else {
69 if (i+1 < inlen) *p++ = codes[(((b & 0xf) << 2)) & 0x3F];
70 }
71 }
72
73 /* append a NULL byte */
74 *p = '\0';
75
76 /* return ok */
77 *outlen = (unsigned long)(p - out); /* the length without terminating NUL */
78 return CRYPT_OK;
79 }
80
81 #if defined(LTC_BASE64)
82 /**
83 base64 Encode a buffer (NUL terminated)
84 @param in The input buffer to encode
85 @param inlen The length of the input buffer
86 @param out [out] The destination of the base64 encoded data
87 @param outlen [in/out] The max size and resulting size
88 @return CRYPT_OK if successful
89 */
base64_encode(const unsigned char * in,unsigned long inlen,char * out,unsigned long * outlen)90 int base64_encode(const unsigned char *in, unsigned long inlen,
91 char *out, unsigned long *outlen)
92 {
93 return _base64_encode_internal(in, inlen, out, outlen, codes_base64, 1);
94 }
95 #endif /* LTC_BASE64 */
96
97
98 #if defined(LTC_BASE64_URL)
99 /**
100 base64 (URL Safe, RFC 4648 section 5) Encode a buffer (NUL terminated)
101 @param in The input buffer to encode
102 @param inlen The length of the input buffer
103 @param out [out] The destination of the base64 encoded data
104 @param outlen [in/out] The max size and resulting size
105 @return CRYPT_OK if successful
106 */
base64url_encode(const unsigned char * in,unsigned long inlen,char * out,unsigned long * outlen)107 int base64url_encode(const unsigned char *in, unsigned long inlen,
108 char *out, unsigned long *outlen)
109 {
110 return _base64_encode_internal(in, inlen, out, outlen, codes_base64url, 0);
111 }
112
base64url_strict_encode(const unsigned char * in,unsigned long inlen,char * out,unsigned long * outlen)113 int base64url_strict_encode(const unsigned char *in, unsigned long inlen,
114 char *out, unsigned long *outlen)
115 {
116 return _base64_encode_internal(in, inlen, out, outlen, codes_base64url, 1);
117 }
118 #endif /* LTC_BASE64_URL */
119
120 #endif
121
122
123 /* ref: $Format:%D$ */
124 /* git commit: $Format:%H$ */
125 /* commit time: $Format:%ai$ */
126