3. The method as claimed in claim 1 , wherein said creating the two or more encrypted keywords comprises: using a function J=rH 1 (W)P 0 +rQ t and N=r·P 0 , where r is a random number, H 1 is a hash function, W is the generated keyword, P 0 is a generator of a group G1, and Q t is a public key.
3. The method as claimed in claim 1 , wherein said creating the two or more encrypted keywords comprises: using a function J=rH 1 (W)P 0 +rQ t and N=r·P 0 , where r is a random number, H 1 is a hash function, W is the generated keyword, P 0 is a generator of a group G1, and Q t is a public key. 4. The method as claimed in claim 3 , wherein said group G1 is a cyclic group of a predefined order (n).