South Korean Internet banking systems have a unique way of enforcing security controls. Users are obliged to install proprietary security software – typically an ActiveX plugin that implements a bundle of protection mechanisms in the user’s browser. The banks and their software suppliers claim that this provides trustworthy user platforms. One side-effect is that almost everyone in Korea uses IE rather than other browsers. We conducted a survey of bank customers who use both Korean and other banking services, and found that the Korean banks ’ proprietary mechanisms impose significant usability penalties. Usability here is strongly correlated with compatability: Korean users have become stuck in an isolated backwater, and have not benefited from all the advances in mainstream browser and security technology. The proprietary mechanisms fail to provide a trustworthy platform; what’s more, alternative strategies based on trustworthy computing techniques are quite likely to suffer from the same usability problems. We conclude that transaction authentication may be the least bad of the available options. 1

Abstract. At CCS’11 a new chosen-ciphertext attack on XML Encryption [12] has been presented. This attack is of high relevance, since it allows to decrypt arbitrary encrypted XML payload by issuing 14 server requests per byte on average. In this paper we discuss several countermeasures against this attack, which have been considered by different framework developers for different scenarios. We analyze the scenarios and show why these countermeasures do not work. Thereby, we motivate for application of authenticated encryption in the XML Encryption specification. 1

Abstract. We show how to exploit the encrypted key import functions of a variety of different cryptographic devices to reveal the imported key. The attacks are padding oracle attacks, where error messages resulting from incorrectly padded plaintexts are used as a side channel. In the asymmetric encryption case, we modify and improve Bleichenbacher’s attack on RSA PKCS#1v1.5 padding, giving new cryptanalysis that allows us to carry out the ‘million message attack ’ in a mean of 49 000 and median of 14 500 oracle calls in the case of cracking an unknown valid ciphertext under a 1024 bit key (the original algorithm takes a mean of 215 000 and a median of 163 000 in the same case). We show how implementation details of certain devices admit an attack that requires only 9 400 operations on average (3 800 median). For the symmetric case, we adapt Vaudenay’s CBC attack, which is already highly efficient. We demonstrate the vulnerabilities on a number of commercially available cryptographic devices, including security tokens, smartcards and the Estonian electronic ID card. The attacks are efficient enough to be practical: we give timing details for all the devices found to be vulnerable, showing how our optimisations make a qualitative difference to the practicality of the attack. We give mathematical analysis of the effectiveness of the attacks, extensive empirical results, and a discussion of countermeasures and manufacturer reaction. 1