I have a question about generateSecret

[BirdKing]

Hello,
I have a question about KeyAgreement.generateSecret.

In API specification, It descript the Throws of KeyAgreement.generateSecret as:

• CryptoException.ILLEGAL_VALUE if the publicData data format is incorrect, or if the
publicData data is inconsistent with the PrivateKey specified during initialization.
• CryptoException.INVALID_INIT if this KeyAgreement object is not initialized.

The result of generateSecret is a point. And the point maybe point-at-infinity. Or the algorithm ends in projective zero point during this operation.

My question is: Whether I should check the result point is on the curve when the API implemented?

[happy123654]

I think you should check it.

[BirdKing]

Thanks for your answer. I think you are right. Ther error result may belong "the publicData data is inconsistent with the PrivateKey specified during initialization" .

[DaHuFa]

I don't think so.
The "inconsistent" may mean "the public point " not on the curve of the private key. If the result is point-at-infinity, the return value may be 0. After all, the return is "byte length of secret".
All these are my conjectures. I hope it will help you.