Building on the work of Kocher [Koc96], we introduce the notion of side-channel cryptanalysis: cryptanalysis using implementation data. We discuss the notion of side-channel attacks and the vulnerabilities they introduce, demonstrate side-channel attacks against three product ciphers—timing attack against IDEA, processor-flag attack against RC5, and Hamming weight attack against DES—and then ge...

Cloud computing provides an effective business model for the deployment of IT infrastructure, platform, and software services. Often, facilities are outsourced to cloud providers and this offers the service consumer virtualization technologies without the added cost burden of development. However, virtualization introduces serious threats to service delivery such as Denial of Service (DoS) atta...

Side Channel Attacks exploit information that leaks from a cryptographic device. Power Analysis is a kind of side channel attack which reveals the key of cryptographic device by analyzing its power consumption. Power analysis attack causes serious threat to the security of cryptographic devices. Differential Power Analysis Attack is most widely used against embedded devices but suffers from few...

Side channel attacks break the secret key of a cryptosystem using channels such as sound, heat, time and power consumption which are originally not intended to leak such information. Power analysis is a branch of side channel attacks where power consumption data is used as the side channel to attack the system. First using a device like an oscilloscope power traces are collected when the crypto...

We propose a new scheme of attack on the Microsoft’s ASIRRA CAPTCHA which represents a significant shortcut to the intended attacking path, as it is not based in any advance in the state of the art on the field of image recognition. After studying the ASIRRA Public Corpus, we conclude that the security margin as stated by their authors seems to be quite optimistic. Then, we analyze which of the...

While algebraic side-channel attack (ASCA) has been successful in breaking simple cryptographic algorithms, it has never been done on larger or more complex algorithms such as Twofish. Compared to other algorithms that ASCA has been used on, Twofish is more difficult to attack due to the key-dependent S-boxes as well as the complex key scheduling. In this paper, we propose the first algebraic s...

We experimentally evaluate program transformations for removing timing side-channel vulnerabilities wrt. security and overhead. Our study of four well-known transformations confirms that their performance overhead differs substantially. A novelty of our work is the empirical investigation of channel bandwidths, which clarifies that the transformations also differ wrt. how much security they add...

1 We describe a side-channel attack on a substitution block, which is usually implemented as a table lookup operation. In particular, we have investigated smartcard implementations. The attack is based on the identifying equal intermediate results from power measurements while the actual values of these intermediates remain unknown. A powerful attack on substitution blocks can be mounted if the...

Insertion of scan chains is the most common technique to ensure observability and controllability of sequential elements in an IC. However, when the chip deals with secret information, the scan chain can be used as back door for accessing secret (or hidden) information, and thus jeopardize the overall security. Several scan-based attacks on cryptographic functions have been described and shown ...

Covert channels are a fundamental concept for cryptanalytic side-channel attacks. Covert timing channels use latency to carry data, and are the foundation for timing and cache-timing attacks. Covert storage channels instead utilize existing system bits to carry data, and are not historically used for cryptanalytic side-channel attacks. This paper introduces a new storage channel made available ...