diff --git a/crypto/mime.go b/crypto/mime.go
index 1c8581e..65dc89d 100644
--- a/crypto/mime.go
+++ b/crypto/mime.go
@@ -73,8 +73,7 @@ func prioritizeSignatureErrors(signatureErrs ...*SignatureVerificationError) (ma
 
 func separateSigError(err error) (*SignatureVerificationError, error) {
 	sigErr := &SignatureVerificationError{}
-	isSigError := errors.As(err, sigErr)
-	if isSigError {
+	if errors.As(err, sigErr) {
 		return sigErr, nil
 	}
 	return nil, err
diff --git a/crypto/signature_collector.go b/crypto/signature_collector.go
index fc7476a..5b96a0a 100644
--- a/crypto/signature_collector.go
+++ b/crypto/signature_collector.go
@@ -100,7 +100,7 @@ func (sc *SignatureCollector) Accept(
 	str, _ := ioutil.ReadAll(rawBody)
 	rawBody = bytes.NewReader(str)
 	if sc.keyring != nil {
-		_, err := openpgp.CheckArmoredDetachedSignature(sc.keyring, rawBody, bytes.NewReader(buffer), sc.config)
+		_, err = openpgp.CheckArmoredDetachedSignature(sc.keyring, rawBody, bytes.NewReader(buffer), sc.config)
 
 		switch {
 		case err == nil: