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cloudflare / circl

CIRCL: Cloudflare Interoperable Reusable Cryptographic Library
http://blog.cloudflare.com/introducing-circl
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OPRF - Export Public Key #401

Closed krissully closed 1 year ago

krissully commented 1 year ago

Is there a way to use a private key in pem format when configuring an oprf server?

bwesterb commented 1 year ago

@cjpatton

armfazh commented 1 year ago

The format of a OPRF keys are raw scalar and curve point. https://github.com/cloudflare/circl/blob/main/oprf/keys.go#L21

For example, for P256, the private key is a 32-byte number and the public key is a compressed point in 33 bytes.

Assuming your key.pem was generated as: 

$ openssl ecparam -name prime256v1 -genkey -out key.pem

You can recover the internal values with:

$ openssl ec -in key.pem  -text -noout

In Go, you can do so similarly as in ParseECPrivateKey, but instead use the UnmarshalBinary method from the OPRF package.

armfazh commented 1 year ago

Closing as answered.