Crypter un mot de passe

Bonsoir,
En fait je cherchais un code sql pour que un mot de passe soit crypté avant stockage dans la base et je suis tombé sur ce code la:
SQL> CREATE TABLE demo_users (
id_user NUMBER(12) NOT NULL,
username VARCHAR2(128) NOT NULL,
password VARCHAR2(128) NOT NULL
);

SQL> Table created.

SQL>ALTER TABLE demo_users ADD (
CONSTRAINT id_users_pk PRIMARY KEY (id_user)
);

SQL> Table altered.

SQL>ALTER TABLE demo_users ADD (
CONSTRAINT users_name_uk UNIQUE (username)
);

SQL> Table altered.

SQL>CREATE SEQUENCE demo_users_seq;

SQL> sequence created.



--Création du package pour la sécurisation des informations des utilisateur
SQL> CREATE OR REPLACE PACKAGE demo_user_security AS

FUNCTION GET_HASH (p_username IN VARCHAR2,
p_password IN VARCHAR2)
RETURN VARCHAR2;

PROCEDURE add_user (p_username IN VARCHAR2,
p_password IN VARCHAR2);

PROCEDURE change_password (p_username IN VARCHAR2,
p_old_password IN VARCHAR2,
p_new_password IN VARCHAR2);

PROCEDURE valid_user (p_username IN VARCHAR2,
p_password IN VARCHAR2);

FUNCTION valid_user (p_username IN VARCHAR2,
p_password IN VARCHAR2)
RETURN BOOLEAN;

END;

SQL> package created.

SQL>CREATE OR REPLACE PACKAGE BODY demo_user_security AS

FUNCTION GET_HASH (p_username IN VARCHAR2,
p_password IN VARCHAR2)
RETURN VARCHAR2 AS
v_secur VARCHAR2(30) := 'Test';
BEGIN
-- Pre Oracle 10g
RETURN DBMS_OBFUSCATION_TOOLKIT.MD5(
input_string => UPPER(p_username) || v_secur || UPPER(p_password));

-- Oracle 10g+ : Require EXECUTE on DBMS_CRYPTO
--RETURN DBMS_CRYPTO.HASH(UTL_RAW.CAST_TO_RAW(UPPER(p_username)
--|| v_secur || UPPER(p_password)),DBMS_CRYPTO.HASH_SH1);
END;

PROCEDURE add_user (p_username IN VARCHAR2,
p_password IN VARCHAR2) AS
BEGIN
INSERT INTO demo_users (
id_user,
username,
password
)
VALUES (
demo_users_seq.NEXTVAL,
UPPER(p_username),
GET_HASH(p_username, p_password)
);

COMMIT;
END;

PROCEDURE change_password (p_username IN VARCHAR2,
p_old_password IN VARCHAR2,
p_new_password IN VARCHAR2) AS
v_rowid ROWID;
BEGIN
SELECT rowid
INTO v_rowid
FROM demo_users
WHERE username = UPPER(p_username)
AND password = get_hash(p_username, p_old_password)
FOR UPDATE;

UPDATE demo_users
SET password = get_hash(p_username, p_new_password)
WHERE rowid = v_rowid;

COMMIT;
EXCEPTION
WHEN NO_DATA_FOUND THEN
RAISE_APPLICATION_ERROR(-20010, 'nom utilisateur/mot de passe incorrect.');
END;

PROCEDURE valid_user (p_username IN VARCHAR2,
p_password IN VARCHAR2) AS
v_numy VARCHAR2(1);
BEGIN
SELECT '1'
INTO v_numy
FROM demo_users
WHERE username = UPPER(p_username)
AND password = get_hash(p_username, p_password);
EXCEPTION
WHEN NO_DATA_FOUND THEN
RAISE_APPLICATION_ERROR(-20000, 'nom utilisateur/mot de passe incorrect.');
END;

FUNCTION valid_user (p_username IN VARCHAR2,
p_password IN VARCHAR2)
RETURN BOOLEAN AS
BEGIN
valid_user(p_username, p_password);
RETURN TRUE;
EXCEPTION
WHEN OTHERS THEN
RETURN FALSE;
END;

END;
/
SQL> package body created.


Je l'ai exécuté et jusque la ça marche tout est bon et puis y a ce code la qui marche pas et j'ai pas compris d'ailleurs c'est quoi ce PL/SQL:
--Création des utilisateurs

SQL> exec demo_user_security.add_user('Smith','secret');

PL/SQL procedure successfully completed.

SQL> exec demo_user_security.add_user('William','terces121');
PL/SQL procedure successfully completed.
SQL> select * from demo_users;
ID USERNAME PASSWORD
----------- -----------------------------------------------
1 Smith ãXFõ^C"®W3-E
2 William b¾õmûMÀ*æ"¶ }^

--Ensuite on va vérifier la procédure VALID_USER


SQL> EXEC demo_user_security.valid_user('Smith','secret');

PL/SQL procedure successfully completed.

SQL> EXEC demo_user_security.valid_user('William','bblsld');
BEGIN app_user_security.valid_user('william','bblsld'); END;

*
ERROR at line 1:
ORA-20000: nom utilisateur/mot de passe incorrect.
ORA-06512: at "W2K1.DEMO_USER_SECURITY", line 66
ORA-06512: at line 1

--Ensuite on vérifiéra la fonction VALID_USER.

SQL> SET SERVEROUTPUT ON
SQL> BEGIN
2 IF demo_user_security.valid_user('Smith','secret') THEN
3 DBMS_OUTPUT.PUT_LINE('TRUE');
4 ELSE
5 DBMS_OUTPUT.PUT_LINE('FALSE');
6 END IF;
7 END;
8 /
TRUE

PL/SQL procedure successfully completed.

SQL> BEGIN
2 IF demo_user_security.valid_user('William','bblsld') THEN
3 DBMS_OUTPUT.PUT_LINE('TRUE');
4 ELSE
5 DBMS_OUTPUT.PUT_LINE('FALSE');
6 END IF;
7 END;
8 /
FALSE

PL/SQL procedure successfully completed.

SQL>

--Au final on vérifiéra la procédure CHANGE_PASSWORD.

SQL> exec demo_user_security.change_password('Smith','secret','tresect');

PL/SQL procedure successfully completed.

SQL> exec demo_user_security.change_password('William','vfrdtg','vcftg12');
BEGIN app_user_security.change_password('William','vfrdtg','vfrd14g'); END;


Si quelqu'un peut m'aider svp , tout ce que je veut c'est les mots de passe avant leurs insertion dans la base. Merci d'avance