Oblivious pseudorandom function: Difference between revisions

Revision as of 19:16, 28 January 2024

Revision as of 19:22, 28 January 2024

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// Send request to server to obtain response

ECPoint server responseserverResponse = sendRequest(blindedInput);

// Compute multiplicative inverse of b

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// Unblind the response to produce the result

ECPoint result = ECMultiply(responseserverResponse, i);

// Hash the unblinded result to complete OPRF calculation

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The client computes the multiplicative inverse of the blinding factor. This enables it to reverse the affect of the blinding factor on the result, and obtain the result the server would have returned had the client not blinded the input.

As a final step, to complete the OPRF, the client performs a [[Cryptographic_hash_function|one-way hash]] on the outputresult to ensure the OPRF output is [[Discrete_uniform_distribution|uniform]], completely [[pseudorandom]], and non-invertible.

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The server receives the ''blinded input'' value from the client, and may perform authentication, access control, request throttling, or other security measures before processing the request. It then uses it's own secret, to compute:

<syntaxhighlight lang="java">

ECPoint processRequest(ECPoint blindedInput, Scalar secret) {

// Apply secret to compute the response