One embodiment of the present invention provides a system that produces an object signature for an object, wherein the object comprises a set of features. During operation, the system first initializes a k-dimensional state vector {s.sub.1, s.sub.2, . . . , s.sub.k}containing floating-point numbers. Next, for each occurrence of each feature in the object, the system (1) computes a random-number seed from the feature; (2) generates k pseudo-random floating-point numbers {X.sub.1, X.sub.2, . . . , X.sub.k} using the random-number seed, wherein each X.sub.i(i.epsilon.[1, k]) is generated in accordance with an .alpha.-stable distribution, wherein 1.ltoreq..alpha.<2; and (3) updates each floating-point number s.sub.i in the k-dimensional state vector using an associated pseudo-random floating-point number X.sub.i. The system then produces the object signature for the object by condensing the k-dimensional state vector. Note that using an .alpha.-stable distribution with 1.ltoreq..alpha.<2 to generate the k pseudo-random floating-point numbers for each feature reduces the influence of multiple occurrences of a given feature on the object signature.