add support for ACME compliant certificate authorities

Signed-off-by: Nicola Murino <nicola.murino@gmail.com>

acme/account.go

@@ -0,0 +1,32 @@
+package acme
+
+import (
+	"crypto"
+
+	"github.com/go-acme/lego/v4/registration"
+)
+
+type account struct {
+	Email        string                 `json:"email"`
+	Registration *registration.Resource `json:"registration"`
+	key          crypto.PrivateKey
+}
+
+/** Implementation of the registration.User interface **/
+
+// GetEmail returns the email address for the account.
+func (a *account) GetEmail() string {
+	return a.Email
+}
+
+// GetRegistration returns the server registration.
+func (a *account) GetRegistration() *registration.Resource {
+	return a.Registration
+}
+
+// GetPrivateKey returns the private account key.
+func (a *account) GetPrivateKey() crypto.PrivateKey {
+	return a.key
+}
+
+/** End **/