1,721,163 research outputs found
When filtering is not possible caching negatives with fingerprints comes to the rescue
No full textBloom filters are widely used in networking to accelerate checks and in particular to avoid accessing slow memories when a match will not be found. Unfortunately, filtering requires several on-chip memory bits per element and thus when the tables are large and the on-chip memory small is not applicable. In those cases, caching the most frequently accessed elements on-chip seems the only viable option. However, the key is typically formed by several packet header fields, which means that each cache entry consumes a significant amount of on-chip memory bits. In this paper, an efficient scheme to cache negatives, that is elements that will not find a match on the table is presented. In more detail, the proposed scheme enables the caching of negatives using less than 16 bits per entry regardless of the size of the key. This translates to a reduction of at least 6x in the size of the cache when used for example flow tracking
Anti-evasion technique for Packet Based Pre- filtering for Network Intrusion Detection Systems
No full textOn the use of Karatsuba formula to detect errors in GF((2(n))(2)) multipliers
No full textGalois fields are widely used in cryptographic applications. The detection of an error caused by a fault in a cryptographic circuit is important to avoid undesirable behaviours of the system that could be used to reveal secret information. One of the methods used to avoid these behaviours is the concurrent error detection. Multiplication in finite field is one of the most important operations and is widely used in different cryptographic systems. The authors propose in this study an error-detection method for composite finite-field multipliers based on the use of Karatsuba formula. The Karatsuba formula can be used in GF((2(n))(2)) field to decrease the hardware complexity of the finite-field multiplier. The authors propose a novel finite-field multiplier with concurrent error-detection capabilities based on the Karatsuba formula. How the error-detection capabilities of this multiplier are able to face a wide range of fault-based attacks is also shown
Bitwise Signature Comparison: Enabling more Efficient Similarity Estimation
No full textEstimating the similarity of sets of data is a common operation in computing. Minhash is widely used to estimate similarity by computing a signature for each set and then comparing their signatures. Therefore, signature comparison is an important part of similarity estimation. To make the comparison efficient, the size of the signature components is commonly set to the word size of the processor or to one half or one fourth of it. This enables efficient data manipulation and comparison but is not optimal in terms of storage. For example, 48-bit signatures may be more than enough in many applications but since that size cannot be easily manipulated by most processors, 64-bit signatures are used. This implies a 33.3% memory overhead. In this paper, Bitwise Signature Comparison (BSC), a method that enables the efficient comparison of signature components of any bitwidth is presented and evaluated. The results show that BSC achieves a similar speed to that of the traditional comparison implementation regardless of the size of the signature components. This enables the use of any signature component size enabling better trade-offs in the implementation of similarity estimation sketches
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