We introduce captcha, an automated test that humans can pass, but current computer programs can’t pass: any program that has high success over a captcha can be used to solve an u...
Luis von Ahn, Manuel Blum, Nicholas J. Hopper, Joh...
Cryptographic computations are often carried out on insecure devices for which the threat of key exposure represents a serious concern. Forward security allows one to mitigate the...
Abstract. We propose a simple and efficient construction of a CCAsecure public-key encryption scheme from any CPA-secure identity-based encryption (IBE) scheme. Our construction re...
SecurID is a widely used hardware token for strengthening authentication in a corporate environment. Recently, Biryukov, Lano, and Preneel presented an attack on the alleged SecurI...
A (t, n) threshold signature scheme allows t or more group members to generate signatures on behalf of a group with n members, while any t−1 or less members cannot do the same th...