Rename skSignEd25519 to ykSignEd25519 since it now targets YubiKeys

Author: AGWA

v2/piv/key.go

@@ -1297,7 +1297,7 @@ func (k *keyEd25519) Public() crypto.PublicKey {
 
 func (k *keyEd25519) Sign(rand io.Reader, digest []byte, opts crypto.SignerOpts) ([]byte, error) {
 	return k.auth.do(k.yk, k.pp, func(tx *scTx) ([]byte, error) {
-		return skSignEd25519(tx, k.slot, k.pub, digest)
+		return ykSignEd25519(tx, k.slot, k.pub, digest)
 	})
 }
 
@@ -1400,7 +1400,7 @@ func ykECDHX25519(tx *scTx, slot Slot, pub *ecdh.PublicKey, peer *ecdh.PublicKey
 	return sharedSecret, nil
 }
 
-func skSignEd25519(tx *scTx, slot Slot, pub ed25519.PublicKey, digest []byte) ([]byte, error) {
+func ykSignEd25519(tx *scTx, slot Slot, pub ed25519.PublicKey, digest []byte) ([]byte, error) {
 	// Adaptation of
 	// https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-73-4.pdf#page=118
 	cmd := apdu{