CREATE TABLE a1_test
  (id NUMBER, col VARCHAR2(40)
  );

CREATE OR REPLACE
  FUNCTION A1_ENC_VARCHAR
    (
      V_VARCHAR IN VARCHAR2
    )
    RETURN RAW
  IS
    V_ENC_VARCHAR RAW(500);
    V_KEY RAW(24) := 'FCF50295B0A28167FF88218A2EF8575102A20874305C8F2A';
    V_MOD NUMBER  := SYS.DBMS_CRYPTO.ENCRYPT_AES + SYS.DBMS_CRYPTO.CHAIN_CBC + SYS.DBMS_CRYPTO.PAD_PKCS5;
  BEGIN
    V_ENC_VARCHAR := SYS.DBMS_CRYPTO.ENCRYPT (UTL_RAW.CAST_TO_RAW (V_VARCHAR), V_MOD, V_KEY);
    RETURN V_ENC_VARCHAR;
  END;
  /

CREATE OR REPLACE
FUNCTION A1_DEC_VARCHAR
  (
    V_RAW IN RAW,
    V_KEY IN RAW
  )
  RETURN VARCHAR2
IS
  V_RET VARCHAR2 (500);
  V_DEC_RAW RAW (500);
  V_MOD NUMBER := DBMS_CRYPTO.ENCRYPT_AES + DBMS_CRYPTO.CHAIN_CBC + DBMS_CRYPTO.PAD_PKCS5;
BEGIN
  V_DEC_RAW := DBMS_CRYPTO.DECRYPT (V_RAW, V_MOD, V_KEY);
  V_RET     := UTL_RAW.CAST_TO_VARCHAR2 (V_DEC_RAW);
  RETURN V_RET;
END;
/

return A1_ENC_VARCHAR(:P146_COL);

A1_DEC_VARCHAR(:P146_COL, 'FCF50295B0A28167FF88218A2EF8575102A20874305C8F2A');