2 * Copyright 2011-2018 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>
15 #include "internal/thread_once.h"
19 * Implementation of NIST SP 800-90A CTR DRBG.
21 static void inc_128(RAND_DRBG_CTR *ctr)
25 unsigned char *p = &ctr->V[15];
27 for (i = 0; i < 16; i++, p--) {
32 /* If we didn't wrap around, we're done. */
38 static void ctr_XOR(RAND_DRBG_CTR *ctr, const unsigned char *in, size_t inlen)
42 if (in == NULL || inlen == 0)
46 * Any zero padding will have no effect on the result as we
47 * are XORing. So just process however much input we have.
49 n = inlen < ctr->keylen ? inlen : ctr->keylen;
50 for (i = 0; i < n; i++)
52 if (inlen <= ctr->keylen)
55 n = inlen - ctr->keylen;
57 /* Should never happen */
60 for (i = 0; i < n; i++)
61 ctr->V[i] ^= in[i + ctr->keylen];
65 * Process a complete block using BCC algorithm of SP 800-90A 10.3.3
67 __owur static int ctr_BCC_block(RAND_DRBG_CTR *ctr, unsigned char *out,
68 const unsigned char *in)
70 int i, outlen = AES_BLOCK_SIZE;
72 for (i = 0; i < 16; i++)
75 if (!EVP_CipherUpdate(ctr->ctx_df, out, &outlen, out, AES_BLOCK_SIZE)
76 || outlen != AES_BLOCK_SIZE)
83 * Handle several BCC operations for as much data as we need for K and X
85 __owur static int ctr_BCC_blocks(RAND_DRBG_CTR *ctr, const unsigned char *in)
87 if (!ctr_BCC_block(ctr, ctr->KX, in)
88 || !ctr_BCC_block(ctr, ctr->KX + 16, in))
90 if (ctr->keylen != 16 && !ctr_BCC_block(ctr, ctr->KX + 32, in))
96 * Initialise BCC blocks: these have the value 0,1,2 in leftmost positions:
99 __owur static int ctr_BCC_init(RAND_DRBG_CTR *ctr)
101 memset(ctr->KX, 0, 48);
102 memset(ctr->bltmp, 0, 16);
103 if (!ctr_BCC_block(ctr, ctr->KX, ctr->bltmp))
106 if (!ctr_BCC_block(ctr, ctr->KX + 16, ctr->bltmp))
108 if (ctr->keylen != 16) {
110 if (!ctr_BCC_block(ctr, ctr->KX + 32, ctr->bltmp))
117 * Process several blocks into BCC algorithm, some possibly partial
119 __owur static int ctr_BCC_update(RAND_DRBG_CTR *ctr,
120 const unsigned char *in, size_t inlen)
122 if (in == NULL || inlen == 0)
125 /* If we have partial block handle it first */
126 if (ctr->bltmp_pos) {
127 size_t left = 16 - ctr->bltmp_pos;
129 /* If we now have a complete block process it */
131 memcpy(ctr->bltmp + ctr->bltmp_pos, in, left);
132 if (!ctr_BCC_blocks(ctr, ctr->bltmp))
140 /* Process zero or more complete blocks */
141 for (; inlen >= 16; in += 16, inlen -= 16) {
142 if (!ctr_BCC_blocks(ctr, in))
146 /* Copy any remaining partial block to the temporary buffer */
148 memcpy(ctr->bltmp + ctr->bltmp_pos, in, inlen);
149 ctr->bltmp_pos += inlen;
154 __owur static int ctr_BCC_final(RAND_DRBG_CTR *ctr)
156 if (ctr->bltmp_pos) {
157 memset(ctr->bltmp + ctr->bltmp_pos, 0, 16 - ctr->bltmp_pos);
158 if (!ctr_BCC_blocks(ctr, ctr->bltmp))
164 __owur static int ctr_df(RAND_DRBG_CTR *ctr,
165 const unsigned char *in1, size_t in1len,
166 const unsigned char *in2, size_t in2len,
167 const unsigned char *in3, size_t in3len)
169 static unsigned char c80 = 0x80;
171 unsigned char *p = ctr->bltmp;
172 int outlen = AES_BLOCK_SIZE;
174 if (!ctr_BCC_init(ctr))
182 inlen = in1len + in2len + in3len;
183 /* Initialise L||N in temporary block */
184 *p++ = (inlen >> 24) & 0xff;
185 *p++ = (inlen >> 16) & 0xff;
186 *p++ = (inlen >> 8) & 0xff;
189 /* NB keylen is at most 32 bytes */
193 *p = (unsigned char)((ctr->keylen + 16) & 0xff);
195 if (!ctr_BCC_update(ctr, in1, in1len)
196 || !ctr_BCC_update(ctr, in2, in2len)
197 || !ctr_BCC_update(ctr, in3, in3len)
198 || !ctr_BCC_update(ctr, &c80, 1)
199 || !ctr_BCC_final(ctr))
202 if (!EVP_CipherInit_ex(ctr->ctx, ctr->cipher, NULL, ctr->KX, NULL, 1))
204 /* X follows key K */
205 if (!EVP_CipherUpdate(ctr->ctx, ctr->KX, &outlen, ctr->KX + ctr->keylen,
207 || outlen != AES_BLOCK_SIZE)
209 if (!EVP_CipherUpdate(ctr->ctx, ctr->KX + 16, &outlen, ctr->KX,
211 || outlen != AES_BLOCK_SIZE)
213 if (ctr->keylen != 16)
214 if (!EVP_CipherUpdate(ctr->ctx, ctr->KX + 32, &outlen, ctr->KX + 16,
216 || outlen != AES_BLOCK_SIZE)
222 * NB the no-df Update in SP800-90A specifies a constant input length
223 * of seedlen, however other uses of this algorithm pad the input with
224 * zeroes if necessary and have up to two parameters XORed together,
225 * so we handle both cases in this function instead.
227 __owur static int ctr_update(RAND_DRBG *drbg,
228 const unsigned char *in1, size_t in1len,
229 const unsigned char *in2, size_t in2len,
230 const unsigned char *nonce, size_t noncelen)
232 RAND_DRBG_CTR *ctr = &drbg->data.ctr;
233 int outlen = AES_BLOCK_SIZE;
235 /* correct key is already set up. */
237 if (!EVP_CipherUpdate(ctr->ctx, ctr->K, &outlen, ctr->V, AES_BLOCK_SIZE)
238 || outlen != AES_BLOCK_SIZE)
241 /* If keylen longer than 128 bits need extra encrypt */
242 if (ctr->keylen != 16) {
244 if (!EVP_CipherUpdate(ctr->ctx, ctr->K+16, &outlen, ctr->V,
246 || outlen != AES_BLOCK_SIZE)
250 if (!EVP_CipherUpdate(ctr->ctx, ctr->V, &outlen, ctr->V, AES_BLOCK_SIZE)
251 || outlen != AES_BLOCK_SIZE)
254 /* If 192 bit key part of V is on end of K */
255 if (ctr->keylen == 24) {
256 memcpy(ctr->V + 8, ctr->V, 8);
257 memcpy(ctr->V, ctr->K + 24, 8);
260 if ((drbg->flags & RAND_DRBG_FLAG_CTR_NO_DF) == 0) {
261 /* If no input reuse existing derived value */
262 if (in1 != NULL || nonce != NULL || in2 != NULL)
263 if (!ctr_df(ctr, in1, in1len, nonce, noncelen, in2, in2len))
265 /* If this a reuse input in1len != 0 */
267 ctr_XOR(ctr, ctr->KX, drbg->seedlen);
269 ctr_XOR(ctr, in1, in1len);
270 ctr_XOR(ctr, in2, in2len);
273 if (!EVP_CipherInit_ex(ctr->ctx, ctr->cipher, NULL, ctr->K, NULL, 1))
278 __owur static int drbg_ctr_instantiate(RAND_DRBG *drbg,
279 const unsigned char *entropy, size_t entropylen,
280 const unsigned char *nonce, size_t noncelen,
281 const unsigned char *pers, size_t perslen)
283 RAND_DRBG_CTR *ctr = &drbg->data.ctr;
288 memset(ctr->K, 0, sizeof(ctr->K));
289 memset(ctr->V, 0, sizeof(ctr->V));
290 if (!EVP_CipherInit_ex(ctr->ctx, ctr->cipher, NULL, ctr->K, NULL, 1))
292 if (!ctr_update(drbg, entropy, entropylen, pers, perslen, nonce, noncelen))
297 __owur static int drbg_ctr_reseed(RAND_DRBG *drbg,
298 const unsigned char *entropy, size_t entropylen,
299 const unsigned char *adin, size_t adinlen)
303 if (!ctr_update(drbg, entropy, entropylen, adin, adinlen, NULL, 0))
308 __owur static int drbg_ctr_generate(RAND_DRBG *drbg,
309 unsigned char *out, size_t outlen,
310 const unsigned char *adin, size_t adinlen)
312 RAND_DRBG_CTR *ctr = &drbg->data.ctr;
314 if (adin != NULL && adinlen != 0) {
315 if (!ctr_update(drbg, adin, adinlen, NULL, 0, NULL, 0))
317 /* This means we reuse derived value */
318 if ((drbg->flags & RAND_DRBG_FLAG_CTR_NO_DF) == 0) {
327 int outl = AES_BLOCK_SIZE;
331 /* Use K as temp space as it will be updated */
332 if (!EVP_CipherUpdate(ctr->ctx, ctr->K, &outl, ctr->V,
334 || outl != AES_BLOCK_SIZE)
336 memcpy(out, ctr->K, outlen);
339 if (!EVP_CipherUpdate(ctr->ctx, out, &outl, ctr->V, AES_BLOCK_SIZE)
340 || outl != AES_BLOCK_SIZE)
348 if (!ctr_update(drbg, adin, adinlen, NULL, 0, NULL, 0))
353 static int drbg_ctr_uninstantiate(RAND_DRBG *drbg)
355 EVP_CIPHER_CTX_free(drbg->data.ctr.ctx);
356 EVP_CIPHER_CTX_free(drbg->data.ctr.ctx_df);
357 OPENSSL_cleanse(&drbg->data.ctr, sizeof(drbg->data.ctr));
361 static RAND_DRBG_METHOD drbg_ctr_meth = {
362 drbg_ctr_instantiate,
365 drbg_ctr_uninstantiate
368 int drbg_ctr_init(RAND_DRBG *drbg)
370 RAND_DRBG_CTR *ctr = &drbg->data.ctr;
373 switch (drbg->type) {
375 /* This can't happen, but silence the compiler warning. */
377 case NID_aes_128_ctr:
379 ctr->cipher = EVP_aes_128_ecb();
381 case NID_aes_192_ctr:
383 ctr->cipher = EVP_aes_192_ecb();
385 case NID_aes_256_ctr:
387 ctr->cipher = EVP_aes_256_ecb();
391 drbg->meth = &drbg_ctr_meth;
393 ctr->keylen = keylen;
394 if (ctr->ctx == NULL)
395 ctr->ctx = EVP_CIPHER_CTX_new();
396 if (ctr->ctx == NULL)
398 drbg->strength = keylen * 8;
399 drbg->seedlen = keylen + 16;
401 if ((drbg->flags & RAND_DRBG_FLAG_CTR_NO_DF) == 0) {
402 /* df initialisation */
403 static const unsigned char df_key[32] = {
404 0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,
405 0x08,0x09,0x0a,0x0b,0x0c,0x0d,0x0e,0x0f,
406 0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,
407 0x18,0x19,0x1a,0x1b,0x1c,0x1d,0x1e,0x1f
410 if (ctr->ctx_df == NULL)
411 ctr->ctx_df = EVP_CIPHER_CTX_new();
412 if (ctr->ctx_df == NULL)
414 /* Set key schedule for df_key */
415 if (!EVP_CipherInit_ex(ctr->ctx_df, ctr->cipher, NULL, df_key, NULL, 1))
418 drbg->min_entropylen = ctr->keylen;
419 drbg->max_entropylen = DRBG_MINMAX_FACTOR * drbg->min_entropylen;
420 drbg->min_noncelen = drbg->min_entropylen / 2;
421 drbg->max_noncelen = DRBG_MINMAX_FACTOR * drbg->min_noncelen;
422 drbg->max_perslen = DRBG_MAX_LENGTH;
423 drbg->max_adinlen = DRBG_MAX_LENGTH;
425 drbg->min_entropylen = drbg->seedlen;
426 drbg->max_entropylen = drbg->seedlen;
428 drbg->min_noncelen = 0;
429 drbg->max_noncelen = 0;
430 drbg->max_perslen = drbg->seedlen;
431 drbg->max_adinlen = drbg->seedlen;
434 drbg->max_request = 1 << 16;