2 * Copyright 2011-2017 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
12 #include <openssl/crypto.h>
13 #include <openssl/err.h>
14 #include <openssl/rand.h>
16 #include "internal/thread_once.h"
19 * Implementation of NIST SP 800-90A CTR DRBG.
22 static void inc_128(RAND_DRBG_CTR
*ctr
)
26 unsigned char *p
= &ctr
->V
[15];
28 for (i
= 0; i
< 16; i
++, p
--) {
33 /* If we didn't wrap around, we're done. */
39 static void ctr_XOR(RAND_DRBG_CTR
*ctr
, const unsigned char *in
, size_t inlen
)
43 if (in
== NULL
|| inlen
== 0)
47 * Any zero padding will have no effect on the result as we
48 * are XORing. So just process however much input we have.
50 n
= inlen
< ctr
->keylen
? inlen
: ctr
->keylen
;
51 for (i
= 0; i
< n
; i
++)
53 if (inlen
<= ctr
->keylen
)
56 n
= inlen
- ctr
->keylen
;
58 /* Should never happen */
61 for (i
= 0; i
< n
; i
++)
62 ctr
->V
[i
] ^= in
[i
+ ctr
->keylen
];
66 * Process a complete block using BCC algorithm of SP 800-90A 10.3.3
68 static void ctr_BCC_block(RAND_DRBG_CTR
*ctr
, unsigned char *out
,
69 const unsigned char *in
)
73 for (i
= 0; i
< 16; i
++)
75 AES_encrypt(out
, out
, &ctr
->df_ks
);
80 * Handle several BCC operations for as much data as we need for K and X
82 static void ctr_BCC_blocks(RAND_DRBG_CTR
*ctr
, const unsigned char *in
)
84 ctr_BCC_block(ctr
, ctr
->KX
, in
);
85 ctr_BCC_block(ctr
, ctr
->KX
+ 16, in
);
86 if (ctr
->keylen
!= 16)
87 ctr_BCC_block(ctr
, ctr
->KX
+ 32, in
);
91 * Initialise BCC blocks: these have the value 0,1,2 in leftmost positions:
94 static void ctr_BCC_init(RAND_DRBG_CTR
*ctr
)
96 memset(ctr
->KX
, 0, 48);
97 memset(ctr
->bltmp
, 0, 16);
98 ctr_BCC_block(ctr
, ctr
->KX
, ctr
->bltmp
);
100 ctr_BCC_block(ctr
, ctr
->KX
+ 16, ctr
->bltmp
);
101 if (ctr
->keylen
!= 16) {
103 ctr_BCC_block(ctr
, ctr
->KX
+ 32, ctr
->bltmp
);
108 * Process several blocks into BCC algorithm, some possibly partial
110 static void ctr_BCC_update(RAND_DRBG_CTR
*ctr
,
111 const unsigned char *in
, size_t inlen
)
113 if (in
== NULL
|| inlen
== 0)
116 /* If we have partial block handle it first */
117 if (ctr
->bltmp_pos
) {
118 size_t left
= 16 - ctr
->bltmp_pos
;
120 /* If we now have a complete block process it */
122 memcpy(ctr
->bltmp
+ ctr
->bltmp_pos
, in
, left
);
123 ctr_BCC_blocks(ctr
, ctr
->bltmp
);
130 /* Process zero or more complete blocks */
131 for (; inlen
>= 16; in
+= 16, inlen
-= 16) {
132 ctr_BCC_blocks(ctr
, in
);
135 /* Copy any remaining partial block to the temporary buffer */
137 memcpy(ctr
->bltmp
+ ctr
->bltmp_pos
, in
, inlen
);
138 ctr
->bltmp_pos
+= inlen
;
142 static void ctr_BCC_final(RAND_DRBG_CTR
*ctr
)
144 if (ctr
->bltmp_pos
) {
145 memset(ctr
->bltmp
+ ctr
->bltmp_pos
, 0, 16 - ctr
->bltmp_pos
);
146 ctr_BCC_blocks(ctr
, ctr
->bltmp
);
150 static void ctr_df(RAND_DRBG_CTR
*ctr
,
151 const unsigned char *in1
, size_t in1len
,
152 const unsigned char *in2
, size_t in2len
,
153 const unsigned char *in3
, size_t in3len
)
155 static unsigned char c80
= 0x80;
157 unsigned char *p
= ctr
->bltmp
;
166 inlen
= in1len
+ in2len
+ in3len
;
167 /* Initialise L||N in temporary block */
168 *p
++ = (inlen
>> 24) & 0xff;
169 *p
++ = (inlen
>> 16) & 0xff;
170 *p
++ = (inlen
>> 8) & 0xff;
173 /* NB keylen is at most 32 bytes */
177 *p
= (unsigned char)((ctr
->keylen
+ 16) & 0xff);
179 ctr_BCC_update(ctr
, in1
, in1len
);
180 ctr_BCC_update(ctr
, in2
, in2len
);
181 ctr_BCC_update(ctr
, in3
, in3len
);
182 ctr_BCC_update(ctr
, &c80
, 1);
185 AES_set_encrypt_key(ctr
->KX
, ctr
->keylen
* 8, &ctr
->df_kxks
);
186 /* X follows key K */
187 AES_encrypt(ctr
->KX
+ ctr
->keylen
, ctr
->KX
, &ctr
->df_kxks
);
188 AES_encrypt(ctr
->KX
, ctr
->KX
+ 16, &ctr
->df_kxks
);
189 if (ctr
->keylen
!= 16)
190 AES_encrypt(ctr
->KX
+ 16, ctr
->KX
+ 32, &ctr
->df_kxks
);
194 * NB the no-df Update in SP800-90A specifies a constant input length
195 * of seedlen, however other uses of this algorithm pad the input with
196 * zeroes if necessary and have up to two parameters XORed together,
197 * so we handle both cases in this function instead.
199 static void ctr_update(RAND_DRBG
*drbg
,
200 const unsigned char *in1
, size_t in1len
,
201 const unsigned char *in2
, size_t in2len
,
202 const unsigned char *nonce
, size_t noncelen
)
204 RAND_DRBG_CTR
*ctr
= &drbg
->data
.ctr
;
206 /* ks is already setup for correct key */
208 AES_encrypt(ctr
->V
, ctr
->K
, &ctr
->ks
);
210 /* If keylen longer than 128 bits need extra encrypt */
211 if (ctr
->keylen
!= 16) {
213 AES_encrypt(ctr
->V
, ctr
->K
+ 16, &ctr
->ks
);
216 AES_encrypt(ctr
->V
, ctr
->V
, &ctr
->ks
);
218 /* If 192 bit key part of V is on end of K */
219 if (ctr
->keylen
== 24) {
220 memcpy(ctr
->V
+ 8, ctr
->V
, 8);
221 memcpy(ctr
->V
, ctr
->K
+ 24, 8);
224 if (drbg
->flags
& RAND_DRBG_FLAG_CTR_USE_DF
) {
225 /* If no input reuse existing derived value */
226 if (in1
!= NULL
|| nonce
!= NULL
|| in2
!= NULL
)
227 ctr_df(ctr
, in1
, in1len
, nonce
, noncelen
, in2
, in2len
);
228 /* If this a reuse input in1len != 0 */
230 ctr_XOR(ctr
, ctr
->KX
, drbg
->seedlen
);
232 ctr_XOR(ctr
, in1
, in1len
);
233 ctr_XOR(ctr
, in2
, in2len
);
236 AES_set_encrypt_key(ctr
->K
, drbg
->strength
, &ctr
->ks
);
239 static int drbg_ctr_instantiate(RAND_DRBG
*drbg
,
240 const unsigned char *entropy
, size_t entropylen
,
241 const unsigned char *nonce
, size_t noncelen
,
242 const unsigned char *pers
, size_t perslen
)
244 RAND_DRBG_CTR
*ctr
= &drbg
->data
.ctr
;
249 memset(ctr
->K
, 0, sizeof(ctr
->K
));
250 memset(ctr
->V
, 0, sizeof(ctr
->V
));
251 AES_set_encrypt_key(ctr
->K
, drbg
->strength
, &ctr
->ks
);
252 ctr_update(drbg
, entropy
, entropylen
, pers
, perslen
, nonce
, noncelen
);
256 static int drbg_ctr_reseed(RAND_DRBG
*drbg
,
257 const unsigned char *entropy
, size_t entropylen
,
258 const unsigned char *adin
, size_t adinlen
)
262 ctr_update(drbg
, entropy
, entropylen
, adin
, adinlen
, NULL
, 0);
266 static int drbg_ctr_generate(RAND_DRBG
*drbg
,
267 unsigned char *out
, size_t outlen
,
268 const unsigned char *adin
, size_t adinlen
)
270 RAND_DRBG_CTR
*ctr
= &drbg
->data
.ctr
;
272 if (adin
!= NULL
&& adinlen
!= 0) {
273 ctr_update(drbg
, adin
, adinlen
, NULL
, 0, NULL
, 0);
274 /* This means we reuse derived value */
275 if (drbg
->flags
& RAND_DRBG_FLAG_CTR_USE_DF
) {
286 /* Use K as temp space as it will be updated */
287 AES_encrypt(ctr
->V
, ctr
->K
, &ctr
->ks
);
288 memcpy(out
, ctr
->K
, outlen
);
291 AES_encrypt(ctr
->V
, out
, &ctr
->ks
);
298 ctr_update(drbg
, adin
, adinlen
, NULL
, 0, NULL
, 0);
302 static int drbg_ctr_uninstantiate(RAND_DRBG
*drbg
)
304 OPENSSL_cleanse(&drbg
->data
.ctr
, sizeof(drbg
->data
.ctr
));
308 static RAND_DRBG_METHOD drbg_ctr_meth
= {
309 drbg_ctr_instantiate
,
312 drbg_ctr_uninstantiate
315 int drbg_ctr_init(RAND_DRBG
*drbg
)
317 RAND_DRBG_CTR
*ctr
= &drbg
->data
.ctr
;
322 /* This can't happen, but silence the compiler warning. */
324 case NID_aes_128_ctr
:
327 case NID_aes_192_ctr
:
330 case NID_aes_256_ctr
:
335 drbg
->meth
= &drbg_ctr_meth
;
337 ctr
->keylen
= keylen
;
338 drbg
->strength
= keylen
* 8;
339 drbg
->seedlen
= keylen
+ 16;
341 if (drbg
->flags
& RAND_DRBG_FLAG_CTR_USE_DF
) {
342 /* df initialisation */
343 static unsigned char df_key
[32] = {
344 0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,
345 0x08,0x09,0x0a,0x0b,0x0c,0x0d,0x0e,0x0f,
346 0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,
347 0x18,0x19,0x1a,0x1b,0x1c,0x1d,0x1e,0x1f
349 /* Set key schedule for df_key */
350 AES_set_encrypt_key(df_key
, drbg
->strength
, &ctr
->df_ks
);
352 drbg
->min_entropylen
= ctr
->keylen
;
353 drbg
->max_entropylen
= DRBG_MINMAX_FACTOR
* drbg
->min_entropylen
;
354 drbg
->min_noncelen
= drbg
->min_entropylen
/ 2;
355 drbg
->max_noncelen
= DRBG_MINMAX_FACTOR
* drbg
->min_noncelen
;
356 drbg
->max_perslen
= DRBG_MAX_LENGTH
;
357 drbg
->max_adinlen
= DRBG_MAX_LENGTH
;
359 drbg
->min_entropylen
= drbg
->seedlen
;
360 drbg
->max_entropylen
= drbg
->seedlen
;
362 drbg
->min_noncelen
= 0;
363 drbg
->max_noncelen
= 0;
364 drbg
->max_perslen
= drbg
->seedlen
;
365 drbg
->max_adinlen
= drbg
->seedlen
;
368 drbg
->max_request
= 1 << 16;
369 drbg
->reseed_interval
= MAX_RESEED_INTERVAL
;