Consider Update of `edwards25519.go`

[ghost]

the file edwards25519.go is from 2013:

https://github.com/nknorg/nkn/blob/aa832aae9a4001c70484c9b3001de89fc3f31eb8/crypto/ed25519/edwards25519/edwards25519.go#L1-L2252

It contains a high amount of duplication, but is very difficult to reduce.

Suggestion

Consider switching to a more modern version:

The project https://github.com/FiloSottile/edwards25519 is and option, and it mentions several other options, like using the version include in go:

(see the commit comments for more reasons to update to a newer version)

https://go-review.googlesource.com/c/go/+/276272

Suggested Process

• a pair (core-dev=CD, abstract-dev=AD) execute this rework
• CD/AD: identify the target package
  • AD/CD: validate the identified target-package
• AD: initiate the rework abstractly/mechanically (ideally, but non-achievable: only refactoring)
  • AD: involve CD whenever the domain-knowledge is needed
• CD: verify existent tests, add more tests if necessary

[yilunzhang]

As you can see in the comment section, this file is part of the official Go code (before 1.17). Upgrading to the latest Go internal version (filippo.io/edwards25519) should be good idea.

[ghost]

As you can see

???

I saw it, assumed it was copied in early dev of nkn/ancestor-project, thought "it cannot be the same version today" and naturally aborted refactoring (I aborted ongoing work, without code-level result)

So I found https://github.com/FiloSottile/edwards25519 and finally https://go-review.googlesource.com/c/go/+/276272, with the possibly most important

Intel(R) Core(TM) i5-7400 CPU @ 3.00GHz

name              old time/op    new time/op    delta
KeyGeneration-4     59.5µs ± 1%    26.1µs ± 1%  -56.20%  (p=0.000 n=10+10)
NewKeyFromSeed-4    59.3µs ± 1%    25.8µs ± 1%  -56.48%  (p=0.000 n=9+10)
Signing-4           60.4µs ± 1%    31.4µs ± 1%  -48.05%  (p=0.000 n=10+10)
Verification-4       169µs ± 1%      73µs ± 2%  -56.55%  (p=0.000 n=10+10)

Filed issue here, and expected... An ACK and a starting budget to go on with the general part of this update task.