diff --git a/acme/client.go b/acme/client.go
index 4ca0ab5b..29b28264 100644
--- a/acme/client.go
+++ b/acme/client.go
@@ -37,7 +37,7 @@ type User interface {
 
 type solver interface {
 	CanSolve() bool
-	Solve()
+	Solve(challenge)
 }
 
 // Client is the user-friendy way to ACME
diff --git a/acme/dvsni_challenge.go b/acme/dvsni_challenge.go
index 2cdf0c1d..1eeda0f1 100644
--- a/acme/dvsni_challenge.go
+++ b/acme/dvsni_challenge.go
@@ -6,6 +6,6 @@ func (s *dvsniChallenge) CanSolve() bool {
 	return false
 }
 
-func (s *dvsniChallenge) Solve() {
+func (s *dvsniChallenge) Solve(challenge challenge) {
 
 }
diff --git a/acme/simple_http_challenge.go b/acme/simple_http_challenge.go
index cf203f81..e7cf3e4f 100644
--- a/acme/simple_http_challenge.go
+++ b/acme/simple_http_challenge.go
@@ -6,6 +6,6 @@ func (s *simpleHTTPChallenge) CanSolve() bool {
 	return true
 }
 
-func (s *simpleHTTPChallenge) Solve() {
+func (s *simpleHTTPChallenge) Solve(challenge challenge) {
 
 }