Encryption & Decryption in Oracle

DECLARE

   input_string       VARCHAR2 (200) :=  'Secret Message';

   output_string      VARCHAR2 (200);

   encrypted_raw      RAW (2000);             -- stores encrypted binary text

   decrypted_raw      RAW (2000);             -- stores decrypted binary text

   num_key_bytes      NUMBER := 256/8;        -- key length 256 bits (32 bytes)

   key_bytes_raw      RAW (32);               -- stores 256-bit encryption key

   encryption_type    PLS_INTEGER :=          -- total encryption type

                            DBMS_CRYPTO.ENCRYPT_AES256

                          + DBMS_CRYPTO.CHAIN_CBC

                          + DBMS_CRYPTO.PAD_PKCS5;

BEGIN

   DBMS_OUTPUT.PUT_LINE ( 'Original string: ' || input_string);

   key_bytes_raw := DBMS_CRYPTO.RANDOMBYTES (num_key_bytes);

   encrypted_raw := DBMS_CRYPTO.ENCRYPT

      (

         src => UTL_I18N.STRING_TO_RAW (input_string,  'AL32UTF8'),

         typ => encryption_type,

         key => key_bytes_raw

      );

    -- The encrypted value "encrypted_raw" can be used here

   decrypted_raw := DBMS_CRYPTO.DECRYPT

      (

         src => encrypted_raw,

         typ => encryption_type,

         key => key_bytes_raw

      );

   output_string := UTL_I18N.RAW_TO_CHAR (decrypted_raw, 'AL32UTF8');

   DBMS_OUTPUT.PUT_LINE ('Decrypted string: ' || output_string);

END