/** Length of OPE key, in bytes. */
#define OPE_KEY_LEN 32
-/** Largest value that can be passed to crypto_ope_encrypt() */
-#define OPE_INPUT_MAX 131072
+/** 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)
typedef struct crypto_ope_c crypto_ope_t;