Revisiting software protection

We provide a selective survey on software protection, including approaches to software tamper resistance, obfuscation, software diversity, and white-box cryptography. We review the early literature in the area plus recent activities related to trusted platforms, and discuss challenges and future directions

A Secure Implementation of a Symmetric Encryption Algorithm in White-Box Attack Contexts

In a white-box context, an adversary has total visibility of the implementation of the cryptosystem and full control over its execution platform. As a countermeasure against the threat of key compromise in this context, a new secure implementation of the symmetric encryption algorithm SHARK is proposed. The general approach is to merge several steps of the round function of SHARK into table lookups, blended by randomly generated mixing bijections. We prove the soundness of the implementation of the algorithm and analyze its security and efficiency. The implementation can be used in web hosts, digital right management devices, and mobile devices such as tablets and smart phones. We explain how the design approach can be adapted to other symmetric encryption algorithms with a slight modification

Measuring Performances of a White-Box Approach in the IoT Context

The internet of things (IoT) refers to all the smart objects that are connected to other objects, devices or servers and that are able to collect and share data, in order to "learn" and improve their functionalities. Smart objects suffer from lack of memory and computational power, since they are usually lightweight. Moreover, their security is weakened by the fact that smart objects can be placed in unprotected environments, where adversaries are able to play with the symmetric-key algorithm used and the device on which the cryptographic operations are executed. In this paper, we focus on a family of white-box symmetric ciphers substitution-permutation network (SPN)box, extending and improving our previous paper on the topic presented at WIDECOM2019. We highlight the importance of white-box cryptography in the IoT context, but also the need to have a fast black-box implementation (server-side) of the cipher. We show that, modifying an internal layer of SPNbox, we are able to increase the key length and to improve the performance of the implementation. We measure these improvements (a) on 32/64-bit architectures and (b) in the IoT context by encrypting/decrypting 10,000 payloads of lightweight messaging protocol Message Queuing Telemetry Transport (MQTT)

White-Box Security Notions for Symmetric Encryption Schemes

White-box cryptography has attracted a growing interest from researchers in the last decade. Several white-box implementations of standard block-ciphers (DES, AES) have been proposed but they have all been broken. On the other hand, neither evidence of existence nor proofs of impossibility have been provided for this particular setting. This might be in part because it is still quite unclear what {white-box} cryptography really aims to achieve and which security properties are expected from white-box programs in applications. This paper builds a first step towards a practical answer to this question by translating folklore intuitions behind white-box cryptography into concrete security notions. Specifically, we introduce the notion of white-box compiler that turns a symmetric encryption scheme into randomized white-box programs, and we capture several desired security properties such as one-wayness, incompressibility and traceability for white-box programs. We also give concrete examples of white-box compilers that already achieve some of these notions. Overall, our results open new perspectives on the design of white-box programs that securely implement symmetric encryption

Digital Rights Management and Code Obfuscation

Digital Rights Management (DRM) involves retaining control over digital information, even after it has been made public. Preventing illegal file sharing on the Internet, which is a topic that has recently received a large amount of media attention, is just one instance where DRM is needed. In this thesis, we attempt to create formal definitions for DRM. Currently, there is a lack of such formal definitions, which is one reason why DRM schemes have achieved little success. We will also examine two DRM schemes that can be cracked easily: Microsoft DRM 2. 0, and the Content Scrambling System. We then discuss the reasons why DRM schemes have been unsuccessful so far, and why a good DRM scheme must incorporate secure hardware, secure software, and an efficient legal system. We also briefly discuss several issues related to DRM, such as privacy. Code Obfuscation involves hiding a program's implementation details from an adversary. One application of code obfuscation involves hiding cryptographic keys in encryption and decryption programs for a cryptosystem. Code obfuscation is directly applicable to DRM schemes, where the adversary has access to a program that contains secret information. For example, a music player may contain a secret key that it uses to decrypt content. The secret key must be hidden from the adversary, since otherwise, he/she could use the key to write his/her own decryption program, and distribute it to circumvent the DRM scheme. We discuss the proof from Barak et al that shows that code obfuscation is impossible in general. This, however, does not mean that code obfuscation cannot be achieved in specific cases. We will examine an obfuscated version of the Data Encryption Standard, and discuss the circumstances under which it is insecure. We also examine a toy example of a block cipher called Simple Block Cipher (SBC), and apply obfuscation techniques to SBC to hide the secret key, and then attempt to obtain the secret key