Oracle9i Supplied PL/SQL Packages and Types Reference Release 1 (9.0.1) Part Number A89852-02 |
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DBMS_OBFUSCATION_TOOLKIT , 3 of 5
The purpose of the DESDecrypt procedure is to generate the decrypted form of the input data. An example of the DESDecrypt procedure appears at the end of this chapter.
Table 30-3 and Table 30-4 list the parameters for the DESDecrypt syntax, their modes, types, and descriptions.
Parameter Name | Mode | Type | Description |
---|---|---|---|
input |
IN |
RAW |
Data to be decrypted |
key |
IN |
RAW |
Decryption key |
decrypted_data |
OUT |
RAW |
Decrypted data |
Parameter Name | Mode | Type | Description |
---|---|---|---|
input_string |
IN |
VARCHAR2 |
String to be decrypted |
key_string |
IN |
VARCHAR2 |
Decryption key string |
decrypted_string |
OUT |
VARCHAR2 |
Decrypted string |
If the input data or key given to the PL/SQL DESDecrypt function is empty, then Oracle raises ORA error 28231 "Invalid input to Obfuscation toolkit".
If the input data given to the DESDecrypt function is not a multiple of 8 bytes, Oracle raises ORA error 28232 "Invalid input size for Obfuscation toolkit".
If the key length is missing or is less than 8 bytes, then the procedure raises the error ORA-28234 "Key length too short." Note that if larger keys are used, extra bytes are ignored. So a 9-byte key will not generate an exception.
The DES key length for encryption is fixed at 64 bits (of which 56 bits are used); you cannot alter this key length.
A sample PL/SQL program follows. Segments of the code are numbered and contain narrative text explaining portions of the code.
DECLARE input_string VARCHAR2(16) := 'tigertigertigert'; raw_input RAW(128) := UTL_RAW.CAST_TO_RAW(input_string); key_string VARCHAR2(8) := 'scottsco'; raw_key RAW(128) := UTL_RAW.CAST_TO_RAW(key_string); encrypted_raw RAW(2048); encrypted_string VARCHAR2(2048); decrypted_raw RAW(2048); decrypted_string VARCHAR2(2048); error_in_input_buffer_length EXCEPTION; PRAGMA EXCEPTION_INIT(error_in_input_buffer_length, -28232); INPUT_BUFFER_LENGTH_ERR_MSG VARCHAR2(100) := '*** DES INPUT BUFFER NOT A MULTIPLE OF 8 BYTES - IGNORING EXCEPTION ***'; double_encrypt_not_permitted EXCEPTION; PRAGMA EXCEPTION_INIT(double_encrypt_not_permitted, -28233); DOUBLE_ENCRYPTION_ERR_MSG VARCHAR2(100) := '*** CANNOT DOUBLE ENCRYPT DATA - IGNORING EXCEPTION ***'; -- 1. Begin testing raw data encryption and decryption BEGIN dbms_output.put_line('> ========= BEGIN TEST RAW DATA ========='); dbms_output.put_line('> Raw input : ' || UTL_RAW.CAST_TO_VARCHAR2(raw_input)); BEGIN dbms_obfuscation_toolkit.DESEncrypt(input => raw_input, key => raw_key, encrypted_data => encrypted_raw ); dbms_output.put_line('> encrypted hex value : ' || rawtohex(encrypted_raw)); dbms_obfuscation_toolkit.DESDecrypt(input => encrypted_raw, key => raw_key, decrypted_data => decrypted_raw); dbms_output.put_line('> Decrypted raw output : ' || UTL_RAW.CAST_TO_VARCHAR2(decrypted_raw)); dbms_output.put_line('> '); if UTL_RAW.CAST_TO_VARCHAR2(raw_input) = UTL_RAW.CAST_TO_VARCHAR2(decrypted_raw) THEN dbms_output.put_line('> Raw DES Encyption and Decryption successful'); END if; EXCEPTION WHEN error_in_input_buffer_length THEN dbms_output.put_line('> ' || INPUT_BUFFER_LENGTH_ERR_MSG); END; dbms_output.put_line('> '); -- 2. Begin testing string data encryption and decryption dbms_output.put_line('> ========= BEGIN TEST STRING DATA ========='); BEGIN dbms_output.put_line('> input string : ' || input_string); dbms_obfuscation_toolkit.DESEncrypt( input_string => input_string, key_string => key_string, encrypted_string => encrypted_string ); dbms_output.put_line('> encrypted hex value : ' || rawtohex(UTL_RAW.CAST_TO_RAW(encrypted_string))); dbms_obfuscation_toolkit.DESDecrypt( input_string => encrypted_string, key_string => key_string, decrypted_string => decrypted_string ); dbms_output.put_line('> decrypted string output : ' || decrypted_string); if input_string = decrypted_string THEN dbms_output.put_line('> String DES Encyption and Decryption successful'); END if; EXCEPTION WHEN error_in_input_buffer_length THEN dbms_output.put_line(' ' || INPUT_BUFFER_LENGTH_ERR_MSG); END; dbms_output.put_line('> '); END;
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