Remove trillian dependency in p256

crypto/vrf/p256/p256.go

@@ -22,7 +22,6 @@ package p256
 
 import (
 	"bytes"
-	"context"
 	"crypto"
 	"crypto/ecdsa"
 	"crypto/elliptic"
@@ -34,13 +33,9 @@ import (
 	"encoding/binary"
 	"encoding/pem"
 	"errors"
-	"fmt"
 	"math/big"
 
-	"github.com/google/trillian/crypto/keys"
 	"github.com/harmony-one/harmony/crypto/vrf"
-
-	"github.com/golang/protobuf/proto"
 )
 
 var (
@@ -229,23 +224,6 @@ func (pk *PublicKey) ProofToHash(m, proof []byte) (index [32]byte, err error) {
 	return sha256.Sum256(vrf), nil
 }
 
-// NewFromWrappedKey creates a VRF signer object from an encrypted private key.
-// The opaque private key must resolve to an `ecdsa.PrivateKey` in order to work.
-func NewFromWrappedKey(ctx context.Context, wrapped proto.Message) (vrf.PrivateKey, error) {
-	// Unwrap.
-	signer, err := keys.NewSigner(ctx, wrapped)
-	if err != nil {
-		return nil, err
-	}
-
-	switch key := signer.(type) {
-	case *ecdsa.PrivateKey:
-		return NewVRFSigner(key)
-	default:
-		return nil, fmt.Errorf("wrapped key has wrong type: %T, want ecdsa.PrivateKey", key)
-	}
-}
-
 // NewVRFSigner creates a signer object from a private key.
 func NewVRFSigner(key *ecdsa.PrivateKey) (vrf.PrivateKey, error) {
 	if *(key.Params()) != *curve.Params() {