Improved Probabilistic Veri
نویسندگان
چکیده
We present and analyze a probabilistic method for veriica-tion by explicit state enumeration, which improves on the \hashcompact" method of Wolper and Leroy. The hashcompact method maintains a hash table in which compressed values for states instead of full state descrip-tors are stored. This method saves space but allows a non-zero probability of omitting states during veriication, which may cause veriication to miss design errors (i.e. veriication may produce \false positives"). Our method improves on Wolper and Leroy's by calculating the hash and compressed values independently, and by using a speciic hashing scheme that requires a low number of probes in the hash table. The result is a large reduction in the probability of omitting a state. Hence, we can achieve a given upper bound on the probability of omitting a state using fewer bits per compressed state. For example, we can reduce the number of bytes stored for each state from the eight recommended by Wolper and Leroy to only ve, and still enumerate state spaces of up to 80 million reachable states while keeping the probability of missing even one state to less than 0.13%. The new veriication scheme was tried on some large, industrial examples. The results predicted by the theoretical analysis were connrmed by the outcomes of these examples. We also discuss some practical issues in choosing the number of bits for the compressed state representation, along with some of our experiences in implementing the scheme.
منابع مشابه
Improved Probabilistic Veri cation by Hash Compaction
We present and analyze a probabilistic method for veri cation by explicit state enumeration, which improves on the \hashcompact" method of Wolper and Leroy. The hashcompact method maintains a hash table in which compressed values for states instead of full state descriptors are stored. This method saves space but allows a non-zero probability of omitting states during veri cation, which may cau...
متن کاملA New Scheme for Memory - E cient Probabilistic Veri cation
In veri cation by explicit state enumeration, for each reachable state of the protocol being veri ed the full state descriptor is stored in a state table. Two probabilistic methods { bitstate hashing and hash compaction { have been proposed in the literature that store much fewer bits for each state but come at the price of some probability that not all reachable states will be explored during ...
متن کاملProbabilistic Anchor M for Speaker Veri
This paper presents a probabilistic approach for representing a speaker using the anchor modelling technique and discusses the relation between this new approach and the deterministic approach. In the first part, the technique of anchor modelling is presented. Then the new approach, which modelizes the various utterances of a speaker by a normal distribution in the anchor models space, is prese...
متن کاملStop-and-Go-MIXes Providing Probabilistic Anonymity in an Open System
Currently known basic anonymity techniques depend on identity veri cation. If veri cation of user identities is not possible due to the related management overhead or a general lack of information (e.g. on the Internet), an adversary can participate several times in a communication relationship and observe the honest users. In this paper we focus on the problem of providing anonymity without id...
متن کاملDense Probabilistic Encryption
This paper describes a method of dense probabilistic encryption. Previous probabilistic encryption methods require large numbers of random bits and produce large amounts of ciphertext for the encryption of each bit of plaintext. This paper develops a method of probabilistic encryption in which the ratio of ciphertext text size to plaintext size and the proportion of random bits to plaintext can...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 1995