10gR2 encrypt and decrypt function are not working in 11gR2

 Could someone please help me.
Hi all,

i have encrypt and decrypt function which were working fine in 10gR2, we have installed 11gR2 and now these are not working

Functions

create or replace function encrypt_text( p_a in varchar2 )
return varchar2
is
-- Variable for the encryption algorithm:
-- 192-bit AES
-- CBC modifier
-- PKCS#5 padding
v_algorithm PLS_INTEGER :=
    DBMS_CRYPTO.encrypt_aes192
    + DBMS_CRYPTO.chain_cbc
    + DBMS_CRYPTO.pad_pkcs5;

-- The data to be encrypted
v_data_plain VARCHAR2 (40) := p_a; -- 'PlainText';
-- 192-bit (24 bytes) key for AES192
v_key VARCHAR2 (32) := '0(The#'||CHR(183)||'Long%'