Searchable encryption

A method for searchable encryption, comprising:

• extracting a plurality of search terms from at least a part of a data structure;
• calculating a keyed-hash value for a search term of the plurality of search terms and store the keyed-hash value in a list;
• examining a bit in a first predetermined position in the keyed-hash value to obtain the bit;
• performing a first determination to determine if it is true that for at least α of the keyed-hash values in the list the bit has a first value, and for at least α of the keyed-hash values the bit has a second value, wherein α is greater or equal to two and the first value is different to the second value;
• and
• if the first determination is true:
• splitting the list of keyed-hash values into a first list and a second list;
• and
• assigning a first search token value to the first list and second search token value to the second list, such that each search token value is associated with a plurality of search terms.

A computer readable storage medium comprising a set of instructions which, when executed by a processor, cause the processor to:

• extract a plurality of search terms from at least a part of a data structure;
• calculate a keyed-hash value for a search term of the plurality of search terms and store the keyed-hash value in a list;
• examine a bit in a first predetermined position in the keyed-hash value to obtain the value of the bit;
• perform a first determination to determine if it is true that for at least α of the keyed-hash values in the list the value of the bit has a first value, and for at least α of the keyed-hash values the value of the bit has a second value, wherein α is greater or equal to two and the first value is different to the second value;
• and
• if the first determination is true:
• split the list of keyed-hash values into a first list and a second list;
• and
• assign a first search token value to the first list and second search token value to the second list, such that each search token value is associated with a plurality of search terms.