diff --git a/core/interfaces.go b/core/interfaces.go
index 35ebf3896..61d2510e3 100644
--- a/core/interfaces.go
+++ b/core/interfaces.go
@@ -11,4 +11,5 @@ type PolicyAuthority interface {
 	ChallengeTypesFor(identifier.ACMEIdentifier) ([]AcmeChallenge, error)
 	ChallengeTypeEnabled(AcmeChallenge) bool
 	CheckAuthzChallenges(*Authorization) error
+	ValidEmail(address string) error
 }