This example demonstrates a technique for obfuscating data in a database.
package ianywhere.ultralitej.demo; import ianywhere.ultralitej.*; /** * Obfuscate -- sample program to a possible obfuscation of the database. * * Obfuscation is not very good encryption. It merely makes the data unreadable * with a file dumping program. The original data can be probably recovered by * someone with knowledge of the algorithms used. */ public class Obfuscate { /** Create the database. * @return connection for a new database */ private static Connection createDatabase() throws ULjException { ConfigPersistent config = DatabaseManager.createConfigurationFile( "Obfuscate.ulj" ); config.setEncryption( new Obfuscator() ); Connection conn = DatabaseManager.createDatabase( config ); conn.schemaCreateBegin(); TableSchema table_schema = conn.createTable( "Product" ); table_schema.createColumn( "prod_no", Domain.INTEGER ); table_schema.createColumn( "prod_name", Domain.VARCHAR, 32 ); table_schema.createColumn( "price", Domain.NUMERIC, 9, (short)2 ); IndexSchema index_schema = table_schema.createPrimaryIndex( "prime_keys" ); index_schema.addColumn( "prod_no", IndexSchema.ASCENDING ); conn.schemaCreateComplete(); return conn; } /** Add a product row. * @param ri PreparedStatement for the Product table * @param prod_no product number * @param prod_name product name * @param price selling price */ private static void addProduct( PreparedStatement ri, int prod_no, String prod_name, String price ) throws ULjException { ri.set( "prod_no", prod_no ); ri.set( "prod_name", prod_name ); ri.set( "price", price ); ri.execute(); } /** Populate the database. * @param conn connection to database */ private static void populate( Connection conn ) throws ULjException { PreparedStatement ri = conn.prepareStatement( "INSERT INTO Product( prod_no, prod_name, price )" + " VALUES( :prod_no, :prod_name, :price )" ); addProduct( ri, 2001, "blue screw", ".03" ); addProduct( ri, 2002, "red screw", ".09" ); addProduct( ri, 2004, "hammer", "23.99" ); addProduct( ri, 2005, "vise", "39.99" ); ri.close(); conn.commit(); } /** Display contents of Product table. * @param conn connection to database */ private static void displayProducts( Connection conn ) throws ULjException { PreparedStatement stmt = conn.prepareStatement( "SELECT prod_no, prod_name, price FROM Product" + " ORDER BY prod_no" ); ResultSet cursor = stmt.executeQuery(); for( ; cursor.next(); ) { String prod_no = cursor.getString( 1 /* "prod_no" */ ); String prod_name = cursor.getString( 2 /* "prod_name" */ ); String price = cursor.getString( 3 /* "price" */ ); Demo.display( prod_no + " " + prod_name + " " + price ); } cursor.close(); stmt.close(); } /** mainline for program. * @param args command-line arguments (not used) */ public static void main ( String[] args ) { try { Connection conn = createDatabase(); populate( conn ); displayProducts( conn ); conn.release(); } catch( ULjException exc ) { Demo.displayException( exc ); } } /** Class to implement encryption/decryption of the database. */ static class Obfuscator implements EncryptionControl { /** seed for obfuscator */ private int _seed; /** (un)Obfuscate a page. * @param page_no the number of the page being encrypted * @param src the encrypted source page which was read from the database * @param tgt the unencrypted page (filled in by method) */ private void transform( int page_no, byte[] src, byte[] tgt ) { int seed = ( _seed + page_no ) % 256; for( int i = 0; i < src.length; ++i ) { tgt[ i ] = (byte)( seed ^ src[ i ] ); seed = ( seed + 93 ) % 256; } } /** Encrypt a page stored in the database. * @param page_no the number of the page being encrypted * @param src the encrypted source page which was read from the database * @param tgt the unencrypted page (filled in by method) */ public void decrypt( int page_no, byte[] src, byte[] tgt ) throws ULjException { transform( page_no, src, tgt ); } /** Encrypt a page stored in the database. * @param page_no the number of the page being encrypted * @param src the unencrypted source * @param tgt the encrypted target page which will be written to the database (filled in by method) */ public void encrypt( int page_no, byte[] src, byte[] tgt ) throws ULjException { transform( page_no, src, tgt ); } /** Initialize the encryption control with a password. * @param password the password */ public void initialize( String password ) throws ULjException { byte[] bytes = null; try { bytes = password.getBytes( "UTF8" ); } catch( Exception e ) { Demo.display( "Encryption initialization failure" ); throw new ObfuscationError(); } _seed = 0; for( int i = bytes.length; i > 0; ) { _seed ^= bytes[ --i ]; } } } /** Error class for encryption errors. */ static class ObfuscationError extends ULjException { /** Constructor. */ ObfuscationError() { super( "Obfuscation Error" ); } /** * Get the error code, associated with this exception. * @return the error code (from the list at the top of this class) associated * with this exception */ public int getErrorCode() { return ULjException.SQLE_ERROR; } /** Get exception causing this exception, if it exists. * @return null, if there exists no causing exception; otherwise, the exception causing this exception */ public ULjException getCausingException() { return null; } /** Get offset of error within a SQL string. * @return (-1) when there is no SQL string associated with the error message; otherwise, * the (base 0) offset within that string where the error occurred. */ public int getSqlOffset() { return -1; } } } |
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