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.
The first time this routine is invoked (either internally or by the application) the PRNG is seeded using randomness obtained from the xRandomness method of the default sqlite3_vfs object. On all subsequent invocations, the pseudo-randomness is generated internally and without recourse to the sqlite3_vfs xRandomness method.