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Diffstat (limited to 'src/lib/libcrypto/aes/aes_ctr.c')
-rw-r--r--src/lib/libcrypto/aes/aes_ctr.c90
1 files changed, 6 insertions, 84 deletions
diff --git a/src/lib/libcrypto/aes/aes_ctr.c b/src/lib/libcrypto/aes/aes_ctr.c
index f36982be1e..7c9d165d8a 100644
--- a/src/lib/libcrypto/aes/aes_ctr.c
+++ b/src/lib/libcrypto/aes/aes_ctr.c
@@ -49,91 +49,13 @@
49 * 49 *
50 */ 50 */
51 51
52#ifndef AES_DEBUG
53# ifndef NDEBUG
54# define NDEBUG
55# endif
56#endif
57#include <assert.h>
58
59#include <openssl/aes.h> 52#include <openssl/aes.h>
60#include "aes_locl.h" 53#include <openssl/modes.h>
61
62/* NOTE: the IV/counter CTR mode is big-endian. The rest of the AES code
63 * is endian-neutral. */
64
65/* increment counter (128-bit int) by 1 */
66static void AES_ctr128_inc(unsigned char *counter) {
67 unsigned long c;
68
69 /* Grab bottom dword of counter and increment */
70 c = GETU32(counter + 12);
71 c++; c &= 0xFFFFFFFF;
72 PUTU32(counter + 12, c);
73
74 /* if no overflow, we're done */
75 if (c)
76 return;
77
78 /* Grab 1st dword of counter and increment */
79 c = GETU32(counter + 8);
80 c++; c &= 0xFFFFFFFF;
81 PUTU32(counter + 8, c);
82
83 /* if no overflow, we're done */
84 if (c)
85 return;
86
87 /* Grab 2nd dword of counter and increment */
88 c = GETU32(counter + 4);
89 c++; c &= 0xFFFFFFFF;
90 PUTU32(counter + 4, c);
91
92 /* if no overflow, we're done */
93 if (c)
94 return;
95 54
96 /* Grab top dword of counter and increment */
97 c = GETU32(counter + 0);
98 c++; c &= 0xFFFFFFFF;
99 PUTU32(counter + 0, c);
100}
101
102/* The input encrypted as though 128bit counter mode is being
103 * used. The extra state information to record how much of the
104 * 128bit block we have used is contained in *num, and the
105 * encrypted counter is kept in ecount_buf. Both *num and
106 * ecount_buf must be initialised with zeros before the first
107 * call to AES_ctr128_encrypt().
108 *
109 * This algorithm assumes that the counter is in the x lower bits
110 * of the IV (ivec), and that the application has full control over
111 * overflow and the rest of the IV. This implementation takes NO
112 * responsability for checking that the counter doesn't overflow
113 * into the rest of the IV when incremented.
114 */
115void AES_ctr128_encrypt(const unsigned char *in, unsigned char *out, 55void AES_ctr128_encrypt(const unsigned char *in, unsigned char *out,
116 const unsigned long length, const AES_KEY *key, 56 size_t length, const AES_KEY *key,
117 unsigned char ivec[AES_BLOCK_SIZE], 57 unsigned char ivec[AES_BLOCK_SIZE],
118 unsigned char ecount_buf[AES_BLOCK_SIZE], 58 unsigned char ecount_buf[AES_BLOCK_SIZE],
119 unsigned int *num) { 59 unsigned int *num) {
120 60 CRYPTO_ctr128_encrypt(in,out,length,key,ivec,ecount_buf,num,(block128_f)AES_encrypt);
121 unsigned int n;
122 unsigned long l=length;
123
124 assert(in && out && key && counter && num);
125 assert(*num < AES_BLOCK_SIZE);
126
127 n = *num;
128
129 while (l--) {
130 if (n == 0) {
131 AES_encrypt(ivec, ecount_buf, key);
132 AES_ctr128_inc(ivec);
133 }
134 *(out++) = *(in++) ^ ecount_buf[n];
135 n = (n+1) % AES_BLOCK_SIZE;
136 }
137
138 *num=n;
139} 61}