func AddDummyV2S1Signature(manifest []byte) ([]byte, error) {
	key, err := libtrust.GenerateECP256PrivateKey()
	if err != nil {
		return nil, err // Coverage: This can fail only if rand.Reader fails.
	}

	js, err := libtrust.NewJSONSignature(manifest)
	if err != nil {
		return nil, err
	}
	if err := js.Sign(key); err != nil { // Coverage: This can fail basically only if rand.Reader fails.
		return nil, err
	}
	return js.PrettySignature("signatures")
}
func AddDummyV2S1Signature(manifest []byte) ([]byte, error) {
	key, err := libtrust.GenerateECP256PrivateKey()
	if err != nil {
		return nil, err // Coverage: This can fail only if rand.Reader fails.
	}

	js, err := libtrust.NewJSONSignature(manifest)
	if err != nil {
		return nil, err
	}
	if err := js.Sign(key); err != nil { // Coverage: This can fail basically only if rand.Reader fails.
		return nil, err
	}
	return js.PrettySignature("signatures")
}
// AddDummyV2S1Signature adds an JWS signature with a temporary key (i.e. useless) to a v2s1 manifest.
// This is useful to make the manifest acceptable to a Docker Registry (even though nothing needs or wants the JWS signature).