src/lib/crypt_ops/crypto_ope.h

   1 /* Copyright (c) 2018-2020, The Tor Project, Inc. */
   2 /* See LICENSE for licensing information */
   3
   4 /**
   5  * @file crypto_ope.h
   6  * @brief header for crypto_ope.c
   7  **/
   8
   9 #ifndef CRYPTO_OPE_H
  10 #define CRYPTO_OPE_H
  11
  12 #include "orconfig.h"
  13 #include "lib/cc/torint.h"
  14 #include "lib/crypt_ops/crypto_ope.h"
  15 #include "lib/testsupport/testsupport.h"
  16
  17 /** Length of OPE key, in bytes. */
  18 #define OPE_KEY_LEN 32
  19
  20 /** Largest value that can be passed to crypto_ope_encrypt().
  21  *
  22  *  Expressed as 2^18 because the OPE system prefers powers of two.
  23  *
  24  *  The current max value stands for about 70 hours. The rationale here is as
  25  *  follows: The rev counter is the time of seconds since the start of an SRV
  26  *  period. SRVs are useful for about 48 hours (that's how long they stick
  27  *  around on the consensus). Let's also add 12 hours of drift for clock skewed
  28  *  services that might be using an old consensus and we arrive to 60
  29  *  hours. The max value should be beyond that.
  30  */
  31 #define OPE_INPUT_MAX (1<<18)
  32
  33 #define CRYPTO_OPE_ERROR UINT64_MAX
  34
  35 typedef struct crypto_ope_t crypto_ope_t;
  36
  37 crypto_ope_t *crypto_ope_new(const uint8_t *key);
  38 void crypto_ope_free_(crypto_ope_t *ope);
  39 #define crypto_ope_free(ope) \
  40   FREE_AND_NULL(crypto_ope_t, crypto_ope_free_, (ope))
  41
  42 uint64_t crypto_ope_encrypt(const crypto_ope_t *ope, int plaintext);
  43
  44 #ifdef CRYPTO_OPE_PRIVATE
  45 struct aes_cnt_cipher_t;
  46 STATIC struct aes_cnt_cipher_t *ope_get_cipher(const crypto_ope_t *ope,
  47                                               uint32_t initial_idx);
  48 STATIC uint64_t sum_values_from_cipher(struct aes_cnt_cipher_t *c, size_t n);
  49 #endif /* defined(CRYPTO_OPE_PRIVATE) */
  50
  51 #endif /* !defined(CRYPTO_OPE_H) */