[#562] cmd/neofs-node: use NEP-6 wallet for keys

Also use neo-go private key wrapper where possible, as it
already has methods for (un)marshaling.

Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>

cmd/neofs-node/config/control/config.go

@@ -1,6 +1,9 @@
 package controlconfig
 
 import (
+	"fmt"
+
+	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
 	"github.com/nspcc-dev/neofs-node/cmd/neofs-node/config"
 )
 
@@ -18,12 +21,24 @@ const (
 	GRPCEndpointDefault = ""
 )
 
-// AuthorizedKeysString returns string array of "authorized_keys" config
+// AuthorizedKeys parses and returns array of "authorized_keys" config
 // parameter from "control" section.
 //
 // Returns empty list if not set.
-func AuthorizedKeysString(c *config.Config) []string {
-	return config.StringSliceSafe(c.Sub(subsection), "authorized_keys")
+func AuthorizedKeys(c *config.Config) keys.PublicKeys {
+	strKeys := config.StringSliceSafe(c.Sub(subsection), "authorized_keys")
+	pubs := make(keys.PublicKeys, 0, len(strKeys))
+
+	for i := range strKeys {
+		pub, err := keys.NewPublicKeyFromString(strKeys[i])
+		if err != nil {
+			panic(fmt.Errorf("invalid permitted key for Control service %s: %w", strKeys[i], err))
+		}
+
+		pubs = append(pubs, pub)
+	}
+
+	return pubs
 }
 
 // GRPC returns structure that provides access to "grpc" subsection of