void sqlite3_randomness(int N, void *P);
SQLite contains a high-quality pseudo-random number generator (PRNG) used to select random ROWIDs when inserting new records into a table that already uses the largest possible ROWID. The PRNG is also used for the build-in random() and randomblob() SQL functions. This interface allows applications to access the same PRNG for other purposes.
A call to this routine stores N bytes of randomness into buffer P. If N is less than one, then P can be a NULL pointer.
If this routine has not been previously called or if the previous call had N less than one, then the PRNG is seeded using randomness obtained from the xRandomness method of the default sqlite3_vfs object. If the previous call to this routine had an N of 1 or more then the pseudo-randomness is generated internally and without recourse to the sqlite3_vfs xRandomness method.