diff --git a/acme-tinier.pl b/acme-tinier.pl
index 5e877a0..c34cce3 100755
--- a/acme-tinier.pl
+++ b/acme-tinier.pl
@@ -70,8 +70,8 @@ sub send_signed {
 
 	my $b64payload = b64 $json->encode($payload);
 	my $b64protected = b64 $json->encode($protected);
-	my $out = communicate('openssl', 'dgst', '-sha256', '-sign', $account_key,
-		"$b64protected.$b64payload");
+	my $out = communicate('openssl', 'dgst', '-sha256', '-sign',
+		$account_key, "$b64protected.$b64payload");
 	die 'cannot sign request' if $? >> 8;
 	return get $url, $json->encode({
 		header => $header, protected => $b64protected,
@@ -99,7 +99,32 @@ my ($code, $result, $headers) = get "$ca/terms";
 });
 die "cannot register: $code" if $code != 201 && $code != 409;
 
-# Run each domain through the ACME challenge
+# Check if the file is really there, submit an HTTP challenge and wait
+sub verify_http {
+	my ($checked_url, $key_auth, $challenge_uri) = @_;
+	my ($code, $result) = get $checked_url;
+	die "checking $checked_url failed: $code" if $code != 200;
+	die 'challenge contents differ' if $result ne $key_auth;
+
+	($code, $result) = send_signed($challenge_uri, {
+		resource => 'challenge', keyAuthorization => $key_auth
+	});
+	die "challenge submission failed: $code" if $code != 202;
+
+	while (1) {
+		($code, $result) = get $challenge_uri;
+		die "challenge verification failed: $code" if $code >= 400;
+		my $status = $json->decode($result);
+		if ($status->{status} eq 'valid') {
+			last;
+		} elsif ($status->{status} eq 'pending') {
+			sleep 1;
+		} else {
+			die "challenge verification failed: $result";
+		}
+	}
+}
+
 for my $domain (@domains) {
 	my ($code, $result) = send_signed("$ca/acme/new-authz", {
 		resource => 'new-authz',
@@ -113,52 +138,24 @@ for my $domain (@domains) {
 	my $key_auth = "$token.$thumbprint";
 	my $known_path = "$acme_dir/$token";
 
-	# Make the challenge file and check that it can be retrieved
-	open(my $fh, '>', $known_path) or die "cannot write $known_path: $!";
+	open(my $fh, '>', $known_path) or die "cannot write to $known_path: $!";
 	print $fh $key_auth;
 	close $fh;
 
-eval {
-	my $url = "http://$domain/.well-known/acme-challenge/$token";
-	my ($code, $result) = get $url;
-	die "checking $url failed: $code" if $code != 200;
-	die 'challenge contents differ' if $result ne $key_auth;
+	eval { verify_http("http://$domain/.well-known/acme-challenge/$token",
+		$key_auth, $challenge->{uri}) };
 
-	# Submit the challenge and wait for the verification to finish
-	($code, $result) = send_signed($challenge->{uri}, {
-		resource => 'challenge',
-		keyAuthorization => $key_auth
-	});
-	die "challenge submission failed: $code" if $code != 202;
-
-	while (1) {
-		($code, $result) = get $challenge->{uri};
-		die "challenge verification failed: $code" if $code >= 400;
-		my $status = $json->decode($result);
-		if ($status->{status} eq 'valid') {
-			last;
-		} elsif ($status->{status} eq 'pending') {
-			sleep 1;
-		} else {
-			die "challenge verification failed: $result";
-		}
-	}
-};
-
-	# Make sure our file gets deleted and rethrow any error
 	unlink $known_path;
-	die $@ if $@;
+	die "$domain: $@" if $@;
 }
 
-# Get the new certificate and print it in the PEM format
+# Get the new certificate and convert it to the PEM format
 my $der = `openssl req -in '$csr_file' -outform DER`;
 die 'cannot convert CSR' if $?;
 ($code, $result) = send_signed("$ca/acme/new-cert", {
-	resource => 'new-cert',
-	csr => b64 $der
+	resource => 'new-cert', csr => b64 $der
 });
 die "cannot sign certificate: $code" if $code != 201;
 
-print "-----BEGIN CERTIFICATE-----\n"
-	. join("\n", unpack '(A64)*', encode_base64($result, ''))
-	. "\n-----END CERTIFICATE-----\n";
+my $pem = join("\n", unpack '(A64)*', encode_base64($result, ''));
+print "-----BEGIN CERTIFICATE-----\n$pem\n-----END CERTIFICATE-----\n";