void EncryptionControl.encrypt(
    int page_no,
    byte[] src,
    byte[] tgt
) throws ULjException

This method is supplied with an unencrypted byte array, src, and an associated page number. Your method must encrypt or obfuscate src and store the result into the tgt byte array. tgt is then stored into the database.

Any algorithm used must preserve the size of the data (encrypted data is the same length as the original data) and must be able to decrypt partial pages (page 0 is first read and decrypted as a 128 bytes long page and then read and decrypted as a full size page). The src array must not be modified.