Signcryption as a single cryptographic primitive offers both confidentiality and authentication simultaneously. Generally in signcryption schemes, the message is hidden and thus the validity of the ciphertext can be verified only after unsigncrypting the ciphertext. Thus, a third party will not be able to verify whether the ciphertext is valid or not. Signcryption schemes that allow any user to...

Undeniable signatures, introduced by Chaum and van Antwerpen, require a verifier to interact with the signer to verify a signature, and hence allow the signer to control the verifiability of his signatures. Convertible undeniable signatures, introduced by Boyar, Chaum, Damg̊ard, and Pedersen, furthermore allow the signer to convert signatures to publicly verifiable ones by publicizing a verifica...

Private communication over the Internet continues to be a difficult problem. Even if messages are encrypted, it is hard to deliver them without revealing metadata about which pairs of users are communicating. Scalable systems such as Tor are susceptible to traffic analysis. In contrast, the largest-scale systems with metadata privacy require passing all messages through a single server, which p...

The KL-ONE concept langu age provides role-value ma.ps (RVMs) as a concept forming operator that compares sets of role fillers. This is a useful means to specify structural properties of concepts. Recently, it has been shown that concept languages providing RVMs together with some other common concept-forming operators induce an undecidable subsumption problem. Thus, RVMs have been restricted t...

Systems engineering, and especially the modeling of safety critical systems, needs proper means for early Validation and Verification (V&V) to detect critical issues as soon as possible. The objective of our work is to identify a verifiable subset of SysML that is usable by system engineers, while still amenable to automatic transformation towards formal verification tools. As we are interested...

Certified software consists of a machine-executable program plus a formal machine-checkable proof that the software is free of bugs with respect to a claim of dependability. The conventional wisdom is that certified software will never be feasible because the dependability of any real software must also rely on that of its underlying operating system and execution environment which is too low-l...

the most important factor in donor-recipient matching for hematopoietic stem cell transplantation is their hla typing. for many patients, we can not find a full-matched donor. in high risk patients, one locus  mismatched related donors are suitable alternatives. (1, 2) since the matching of patients and their siblings usually is based on low resolution hla typing, the matching of one locus mism...