DR. MIGUEL ÁNGEL OROS HERNÁNDEZ

8. Cracking

Cracking

Magnitude of piracy All kinds of digital content

(music, software, movies) Huge economic

repercussions

Cracking Process of attacking a copy

protection technology One kind of reversing Modification of an

application’s binary to cause or prevent a specific key branch in the program’s execution

Cracking

1. Piratería y protección de copias

2. Tipos de protección

3. Conceptos avanzados de protección

4. Marca de agua

Piratería y protección de copias

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Piratería y protección de copias

Piratería y protección de copias

Applying reverse engineering until the software cracker reaches the subroutine that containts the primary method of protecting the software

Elimination of the expiration period from a time-limited trial of an application

Scanning for the use of a commercial copy protection application (CD, DVD) CloneCD Alcohol 120% Game Jackal Daemon Tools

Piratería y protección de copias

The open architecture of today’s personal computers makes impossible to create an uncrackable copy protection technology

Piratería y protección de copiasClass break

Problem in practically every copy protection technology

Takes place when a security technology or product fails in a way that affects every user of that technology or product, and not just the specific system that is under attack

Huge efforts of developers of copy protection technologies

ProblemPublishing the results of defeating the protection mechanism

Piratería y protección de copiascopy protection mechanism

DefinitionA delicate componentInvisible to legitimate

users

Design considerationsResistance to AttackEnd-User

TransparencyFlexibility

Tipos de protección

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Tipos de protección

Media-Based Protections The primary copy protection

approach in the 1980s Idea: have a program check

the media with which it is shipped and confirm that it is an original

Floppy disks: creating special “bad” sectors

Programs: CopyWrite

Transcopy

Are they legals?

Serial numbers Idea: the software vendor ships

each copy of the software with a unique serial number printed somewhere on the product package or on the media itself

The installation requires this number

If the program is installed, the user is registered

When the user contact customer support, the software vendor can verify that the user has a valid installation of the product

Tipos de protección

Challenge response and online activationsThe program sends a

challenge response (an protocol used for authenticating specific users or computers in networks)

Idea: the both parties share a secret key that is known only to them

Improvement to the serial number

Challenge responseVendor’s approvalCrackable: create a

keygen program that emulates the server´s challegne mechanism and generate a valid response on demand

Tipos de protecciónkeygen

A license or product key generator (sometimes stylized as keygen) is a computer program that generates a product licensing key, serial number, or some other registration information necessary to activate for use a software application

Tipos de protección

Hardware-based protectionsIdea: add a tamper-

proof, non-software-based component into the mix assists in authenticating the running software

Use of attached chip to the computer like USB

Conceptos avanzados de protección

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Conceptos avanzados de protección

Cripto-ProcessorsA well-known software

copy protection approachProposedRobert M. BestIdea: design a

microprocessor that can directly executed encrypted code by decrypting it on the fly

Hard to crack because the decrypted code would never be accessible to attackers

Digital Rights ManagementDRM Models

Encrypting the protect content

Try their best to hide the decryption key and control the path in which content flows after it has been decrypted

Conceptos avanzados de protección

Digital Rights ManagementThe Windows Media

Rights Manager Idea: separate the

media from the licence file (encryption key required to decrypt and playback the media file)

Digital Rights ManagementSecure Audio Path

Attempts to control the flow of copyrighted, unencrypted audio within Windows

Problem: anyone can write a simulated audio device driver that would just steal the decrypted content while the media playback software is sending it to the sound card

Marca de agua

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Marca de agua

Watermaking Processing to adding

an additional “channel” of imperceptible data alongside a visible stream of data

Invisble (or inaudible) data stream that is hidden within the file

Properties Difficult to remove It contains as much

information as possible Imperceptible Difficult to detect Encrypted Robust

Marca de aguaaplicaciones

Enabling authors to embed indentifying information in their intellectual property

Identifying the specific owner of an individual copy by using a watermarked fingerprint

Identifying the original,unmodified data through a validation mark

Bibliografía

Reversing: Secrets of Reverse Engineering Eldad Eilam Wiley Publishing, Inc. 2005

Fin