1 files changed, 46 insertions, 0 deletions
diff --git a/src/lib/crypt_ops/crypto_ope.h b/src/lib/crypt_ops/crypto_ope.h
new file mode 100644
index 0000000000..c62ed2a942
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+++ b/src/lib/crypt_ops/crypto_ope.h
@@ -0,0 +1,46 @@
+/* Copyright (c) 2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef CRYPTO_OPE_H
+#define CRYPTO_OPE_H
+
+#include "orconfig.h"
+#include "lib/cc/torint.h"
+#include "lib/crypt_ops/crypto_ope.h"
+#include "lib/testsupport/testsupport.h"
+
+/** Length of OPE key, in bytes. */
+#define OPE_KEY_LEN 32
+
+/** Largest value that can be passed to crypto_ope_encrypt().
+ *
+ *  Expressed as 2^18 because the OPE system prefers powers of two.
+ *
+ *  The current max value stands for about 70 hours. The rationale here is as
+ *  follows: The rev counter is the time of seconds since the start of an SRV
+ *  period. SRVs are useful for about 48 hours (that's how long they stick
+ *  around on the consensus). Let's also add 12 hours of drift for clock skewed
+ *  services that might be using an old consensus and we arrive to 60
+ *  hours. The max value should be beyond that.
+ */
+#define OPE_INPUT_MAX (1<<18)
+
+#define CRYPTO_OPE_ERROR UINT64_MAX
+
+typedef struct crypto_ope_t crypto_ope_t;
+
+crypto_ope_t *crypto_ope_new(const uint8_t *key);
+void crypto_ope_free_(crypto_ope_t *ope);
+#define crypto_ope_free(ope) \
+  FREE_AND_NULL(crypto_ope_t, crypto_ope_free_, (ope))
+
+uint64_t crypto_ope_encrypt(const crypto_ope_t *ope, int plaintext);
+
+#ifdef CRYPTO_OPE_PRIVATE
+struct aes_cnt_cipher;
+STATIC struct aes_cnt_cipher *ope_get_cipher(const crypto_ope_t *ope,
+                                              uint32_t initial_idx);
+STATIC uint64_t sum_values_from_cipher(struct aes_cnt_cipher *c, size_t n);
+#endif
+
+#endif