BEAN is a newly proposed lightweight stream cipher adopting Fibonacci FCSRs. It is designed for very constrained environments and aims at providing a balance between security, efficiency and cost. A weakness in BEAN was first found by Å gren and Hell in 2011, resulting in a key recovery attack slightly better than brute force. In this paper, we present new correlations between state and keystream with large statistical advantage, leading to a much more efficient key recovery attack. The time and data complexities of this attack are 257.53 and 259.94, respectively. Moreover, two new output functions are provided as alternatives, which are more efficent than the function used in BEAN and are immune to all attacks proposed on the cipher. Also, suggestions for improving the FCSRs are given.

A component connection enables a component to use the functionality of other components directly, without generating adapters or other mechanisms at run-time. In conventional component connection models, the connection between components, particularly third-party components, is very costly for code reuse because the component source code must be modified if the types of requester-side and provider-side are different. This paper proposes a new component model, built upon an existing component architecture, which abandons a component service type and connects components based on a method type collection of the provider and requester components. Our model enables flexible connections owing to relaxed component matching, in which the system that implements our model automatically converts values of parameters, return values, and exceptions between required methods and provided ones within a well-defined range. As a result of experimental evaluations, it is found that our model is superior to conventional models in terms of the component-use cost and the capability of changing connections.