Searchable symmetric encryption: Difference between revisions

Revision as of 22:24, 28 January 2023

Revision as of 12:04, 11 February 2023

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A static SSE scheme consists of three algorithms <math>\mathsf{SSE = (Setup, Token, Search)}</math> that work as follows:

* <math>\mathsf{Setup}</math> takes as input a security parameter <math>k</math> and a document collection <math>\mathbf{D}</math> and outputs a symmetric key <math>K</math>, an encrypted index <math>\mathbf{I}</math>, and an encrypted document collection <math>\mathbf{ED}</math>

* <math>\mathsf{Token}</math> takes as input the secret key <math>K</math> and a keyword <math>w</math> and outputs a search token <math>tk</math>

* <math>\mathsf{Search}</math> takes as input the encrypted index <math>\mathbf{I}</math>, the encrypted document collection <math>\mathbf{ED}</math> and a search token <math>tk</math> and outputs a set of encrypted documents <math>\mathbf{R} \subseteq \mathbf{ED}</math>

A static SSE scheme is used by a client and an untrusted server as follows. The client encrypts its data collection using the <math>\mathsf{Setup}</math> algorithm which returns a secret key <math>K</math> and an encrypted document collection <math>\mathbf{ED}</math>. The client keeps <math>K</math> secret and sends <math>\mathbf{ED}</math> and <math>\mathbf{I}</math> to the untrusted server. To search for a keyword <math>w</math>, the client runs the <math>\mathsf{SearchTokenToken}</math> algorithm on <math>K</math> and <math>w</math> to generate a search token <math>tk</math> which it sends to the server. The server runs Search with <math>\mathbf{ED}</math>, <math>\mathbf{I}</math>, and <math>tk</math> and returns the resulting encrypted documents back to the client.

=== Dynamic SSE ===