SECURE THRESHOLD DECRYPTION PROTOCOL COMPUTATION

摘要

The present invention relates to a method of converting an encrypted data set into an encryption of individual bits representing the data set. Further, the invention relates to a system for converting an encrypted data set into an encryption of individual bits representing the data set. A basic idea of the present invention is to provide a protocol in which it is possible to divide an encryption of a data set in the form of e.g. a biometric feature, such as a number x, where x e {0, 1, ..., n-1 }, into an encryption of respective bits x₀, x₁, ..., x_t-1 forming the number x, where t is the number of bits of the number n-1, without leaking any information about x or its bits x₀, x₁, ..., x_t-1 Hence, the present invention enables splitting of the encryption [[x]] into the respective encrypted bits [[x₀]], [[x₁]], ..., [[x_t-1]] forming the encrypted number x=?I=1ⁿ x_i 2ⁱ.