grant execute on dbms_crypto to system * ERROR at line 1: ORA-00942: table or view does not exist

The error "ORA-00942: table or view does not exist" indicates that the "dbms_crypto" object is not available in the current database schema.

This could be due to the following reasons:
- The object has not been created in the schema.
- The object has not been granted to the user executing the statement.
- The user executing the statement is not connected to the correct schema.

To resolve this error, you can try the following steps:
1. Check if the "dbms_crypto" object exists in the schema by running the command "DESCRIBE dbms_crypto" or "SELECT * FROM dbms_crypto". If it does not exist, you may need to create it.
2. Check if the user executing the statement has been granted access to the "dbms_crypto" object by running the command "SELECT * FROM user_tab_privs WHERE table_name = 'DBMS_CRYPTO'". If the user does not have access, you can grant the necessary privileges using the "GRANT" command.
3. Check if you are connected to the correct schema by running the command "SELECT * FROM user_users". If you are not connected to the correct schema, you can switch to the correct schema using the "ALTER SESSION SET CURRENT_SCHEMA" command.