RFR: 8329538: Accelerate P256 on x86_64 using Montgomery intrinsic [v2]

[Volodymyr Paprotski]

On Tue, 9 Apr 2024 02:01:36 GMT, Anthony Scarpino <ascarpino at openjdk.org> wrote:

>> Volodymyr Paprotski has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   remove use of jdk.crypto.ec
>
> src/java.base/share/classes/sun/security/ec/ECOperations.java line 308:
> 
>> 306: 
>> 307:     /*
>> 308:      * public Point addition. Used by ECDSAOperations
> 
> Was the old description not applicable anymore?   It would be nice to improve on the existing description that shortening it.

Forgot to go back and fix the comment. Fixed..

As for the 'meaning'. Notice the signature of the function changed (i.e. no longer a 'mixed point', but two ProjectivePoints. This is a good idea regardless of Montgomery, but it affects montgomery particularly badly (need to compute zInv for 'no reason'. )

For sake of completeness. Apart from constructor, the 'API' for ECOperations (i.e. as used by ECDHE, ECDSAOperations and KeyGeneration) are these three functions (everything else is used internally by this class)

public void setSum(MutablePoint p, MutablePoint p2)
public MutablePoint multiply(AffinePoint affineP, byte[] s)
public MutablePoint multiply(ECPoint ecPoint, byte[] s)

> src/java.base/share/classes/sun/security/ec/ECOperations.java line 321:
> 
>> 319:         ECOperations ops = this;
>> 320:         if (this.montgomeryOps != null) {
>> 321:             assert p.getField() instanceof IntegerMontgomeryFieldModuloP;
> 
> This should throw a ProviderException, I believe this would throw an AssertionException

Missed this comment. No longer applicable (this.montgomeryOps got refactored away)

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PR Review Comment: https://git.openjdk.org/jdk/pull/18583#discussion_r1578144125
PR Review Comment: https://git.openjdk.org/jdk/pull/18583#discussion_r1578161140