The logic here is that we'll have all binary encoding/decoding done via our io
package, which simplifies error handling. This functionality doesn't belong to
util, so it's moved.
This also expands BufBinWriter with Reset() method to fit the needs of core
package.
ANSI X9.62 says that if x or y coordinate are greater than or equal to
curve.Params().P, the conversion should return an error (see ANSI X9.62:2005
Section A.5.8 Step b, which invokes Section A.5.5, which does the check and
rejects when x or y are too big.
See https://github.com/golang/go/issues/20482 for more details.
PublicKey() for PrivateKey now just can't fail and it makes no sense to return
an error from it. There is a lot of associated functionality for which this
also is true, so adjust it accordingly and simplify a lot of code.
Public key is just a point, so use the coordinates obtained previously to
initialize the PublicKey structure without jumping through the hoops of
encoding/decoding.
As NEO uses P256 we can use standard crypto/elliptic library for almost
everything, the only exception being decompression of the Y coordinate. For
some reason the standard library only supports uncompressed format in its
Marshal()/Unmarshal() functions. elliptic.P256() is known to have
constant-time implementation, so it fixes#245 (and the decompression using
big.Int operates on public key, so nobody really cares about that part being
constant-time).
New decompress function is inspired by
https://stackoverflow.com/questions/46283760, even though the previous one
really did the same thing just in a little less obvious way.
It makes no sense to provide an API for throw-away public keys, so obtain it
via a new real keypair generation where appropriate (and that's only needed
for testing).
pkg/core/transaction/attribute.go:67:14: should omit type uint8 from declaration of var urllen; it will be inferred from the right-hand side
pkg/crypto/keys/publickey.go:184:8: should omit type []byte from declaration of var b; it will be inferred from the right-hand side
pkg/network/payload/version_test.go:15:12: should omit type bool from declaration of var relay; it will be inferred from the right-hand side
Refs. #213.
Fixes things like:
* exported type/method/function X should have comment or be unexported
* comment on exported type/method/function X should be of the form "X ..."
(with optional leading article)
Refs. #213.
And drop associated _pkg.dev remnants (refs. #307).
Original `dev` branch had two separate packages for public and private keys,
but those are so intertwined (`TestHelper` subpackage is a proof) that it's
better unite them and all associated code (like WIF and NEP-2) in one
package. This patch also:
* creates internal `keytestcases` package to share things with wallet (maybe
it'll be changed in some future)
* ports some tests from `dev`
* ports Verify() method for public key from `dev`
* expands TestPrivateKey() with public key check
