diff --git a/policy/policy.go b/policy/policy.go
index 753186a2..5ab2408e 100644
--- a/policy/policy.go
+++ b/policy/policy.go
@@ -76,20 +76,19 @@ func (p Policy) PublicKeyVerifiers(ko map[string][]func(signer.SignerProvider) (
 					}
 				}
 
-				kspv, ok := vp.(*kms.KMSSignerProvider)
-				if !ok {
-					return nil, fmt.Errorf("provided verifier provider is not a KMS verifier provider")
+				if vp != nil {
+					var ok bool
+					ksp, ok = vp.(*kms.KMSSignerProvider)
+					if !ok {
+						return nil, fmt.Errorf("provided verifier provider is not a KMS verifier provider")
+					}
 				}
 
-				verifier, err = kspv.Verifier(context.TODO())
+				verifier, err = ksp.Verifier(context.TODO())
 				if err != nil {
 					return nil, fmt.Errorf("failed to create kms verifier: %w", err)
 				}
 
-				if err != nil {
-					return nil, fmt.Errorf("KMS Key ID recognized but not valid: %w", err)
-				}
-
 			}
 		}
 
diff --git a/policy/policy_test.go b/policy/policy_test.go
index c57fda3e..761237c5 100644
--- a/policy/policy_test.go
+++ b/policy/policy_test.go
@@ -31,6 +31,7 @@ import (
 	"github.com/in-toto/go-witness/attestation/commandrun"
 	"github.com/in-toto/go-witness/cryptoutil"
 	"github.com/in-toto/go-witness/intoto"
+	"github.com/in-toto/go-witness/signer"
 	"github.com/in-toto/go-witness/source"
 	"github.com/invopop/jsonschema"
 	"github.com/stretchr/testify/assert"
@@ -483,7 +484,7 @@ func TestPubKeyVerifiers(t *testing.T) {
 				}
 			}
 
-			verifiers, err := p.PublicKeyVerifiers()
+			verifiers, err := p.PublicKeyVerifiers(map[string][]func(signer.SignerProvider) (signer.SignerProvider, error){})
 			if testCase.expectedErr == nil {
 				assert.NoError(t, err)
 				assert.Len(t, verifiers, testCase.expectedLen)