SmartLock means CAD encryptor, CAD lockor or DWG lockor. SmartLock is a useful tool to protect drawing files, keeping others from modifying or copying your designs, protecting your copyright and enhancing the value of your dwg.

Using SmartLock is the easiest way to lock your dwg files.Locking hundreds of files (about 1M each)only needs a few minutes(about 5-10mins).

Easy to use,only 3 step:
1. Select files ;2. Assign folder to hold locked files;3.Do locking.

SmartLock A-type is a typical encryption. There are multiple measures to ensure the safety of drawings:
1, The development of A-type lock goes deep into the core of AutoCAD and use core techniques. Program structure, data structures and graphical techniques all adopt highly complex models. Anyone who wants to decrypt the files encrypted by A-type lock must also goes into the core of AutoCAD drawing file kernel programming. It's not only highly difficult, but also extremely intensified. Even if the following 2-6 encryption techniques are public, the development of cracking graphics software will also take master at least six months of full-time work.
Without any potential benefits, will anyone try to develop decryption software? Even if the program has been decrypted, the encrypted drawing can not be decoded. (Decrypting program registration and decoding encrypted drawing are totally not the same thing.)
2,As all map objects will be transformed into specific objects, they have unique and complex data structures. Because hundreds of complex data structures and man-made traps exist, like black box,
to explore the data structure (theoretically feasible, because can read binary files) for crack graphics developers will also be a daunting task.
3, Graphics encrypted password will adopt the combined encryption algorithms of RC4 Microsoft Base Cryptographic and DSS Diffie-Hellem.
4, Graphics delegated authority details will adopt the method of drawings fingerprint, using an independent fingerprint for each file and MD5 fingerprint algorithm to ensure that permissions will not be tampered with or replaced.
5, Drawings bound to computer or USB hardware lock have also adopted the MD5 fingerprint sub-algorithms to ensure that permissions will not be tampered with or replaced.
6, All the coordinates, dimensions and other data in drawing will use 512-bit RSA public key and private key synthesis algorithm.

Authority Types: Free to read (read only,no change,no copy etc.)
Additional Password protect
Hard USB key for DWG file(s)
Hard USB key & Additional Password
DWG files bind to specified computer(s)
Detail Authority Rights:

Forbid re-save (Y/N)
Forbid explode (Y)
Forbid copyclip (Y/N)
Forbid copy & mirror (Y/N)
Forbid move / scale / rotate (Y/N)
Forbid plot,dwfout,pdf out (Y/N)
Forbid bitmap out (Y/N)
Forbid delete (Y/N)
Forbid trim / offset / extend / fillet / charm(Y/N)
Forbid object snap (Y/N)
Forbid grip edit (Y/N)
Forbid lineweight change (Y/N)
Forbid linetype change (Y/N)
Forbid linetypescale change(Y/N)
Forbid layer change(Y/N)
Forbid color change(Y/N)
Forbid measure distance & get area(Y/N)
Forbid append new object(Y/N)
Others:
Dwg copyrights' Owner recorded & watermark
Authority user recorded & watermark
publish date recorded & watermark
expired date recorded & watermark
Support AutoCAD 2004-2010

Support: AutoCAD 2004 2005 2006 2007 2008 2009 2010
Specific requirements:
Require that you haved installed AutoCAD, currently supported version is 2004-2010.
As long as AutoCAD to open DWG files can be encrypted.
Despite the encrypted file size is no limit, but it is powerfully recommended dwg file no more than 2M for SmartLock_B.
Do not operate AutoCAD manually when locking.
For SmartLock_B, in the encryption process called AutoCAD environment, not open any of the drawings have been encrypted, otherwise it will cause AutoCAD to quit unexpectedly

The license of this software is Free Trial Software, the price is $369.00, you can free download and get a free trial.