This will work like a charm, please let me know if it did.

CREATE OR REPLACE FUNCTION ENCRYPT_TEST(P_VAL IN VARCHAR2)
RETURN VARCHAR2 AS
BEGIN
RETURN TRIM(DBMS_OBFUSCATION_TOOLKIT.DESENCRYPT(input_string => RPAD(P_VAL, 400), key_string => 'ZZZZZZZZ'));
END;

CREATE OR REPLACE FUNCTION DECRYPT_TEST(P_VAL IN VARCHAR2,
P_KEY IN VARCHAR2)
RETURN VARCHAR2 AS
BEGIN
RETURN TRIM(DBMS_OBFUSCATION_TOOLKIT.DESDecrypt(input_string => RPAD(P_VAL, 400), key_string => P_KEY));
END;

CREATE OR REPLACE VIEW TEST_ENCRYPT AS
SELECT TABLE_NAME, ENCRYPT_TEST(COLUMN_NAME) COLUMN_NAME
FROM ALL_TAB_COLUMNS

SELECT *
FROM TEST_ENCRYPT;

SELECT TABLE_NAME, COLUMN_NAME, DECRYPT_TEST(COLUMN_NAME, 'ZZZZZZZZ')
FROM TEST_ENCRYPT