diff --git a/helper/communicator/config.go b/helper/communicator/config.go
index 7d66254b5..75ac3b2b6 100644
--- a/helper/communicator/config.go
+++ b/helper/communicator/config.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"net"
+	"net/url"
 	"os"
 	"time"
 
@@ -329,3 +330,9 @@ func (c *Config) prepareWinRM(ctx *interpolate.Context) []error {
 
 	return errs
 }
+
+// SSHPublicKeyUrlEncoded returns a string representing the SSH public key
+// encoded in URL format.
+func (c *Config) SSHPublicKeyUrlEncoded() string {
+	return url.PathEscape(string(c.SSHPublicKey))
+}
diff --git a/helper/communicator/config_test.go b/helper/communicator/config_test.go
index c5af24114..9f28c2be5 100644
--- a/helper/communicator/config_test.go
+++ b/helper/communicator/config_test.go
@@ -1,6 +1,7 @@
 package communicator
 
 import (
+	"net/url"
 	"reflect"
 	"testing"
 
@@ -136,6 +137,23 @@ func TestConfig_winrm(t *testing.T) {
 	}
 }
 
+func TestConfig_SSHPublicKeyUrlEncoded(t *testing.T) {
+	c := &Config{
+		SSHPublicKey: []byte("ecdsa-sha2-nistp521 AAAAE2VjZHNhLXNoYTItbmlzdHA1MjEAAAAIbmlzdHA1MjEAAACFBADulbdHCjXhsH8wGtyLhhi3qVvX6M0tGgtousr/DzArwf2KX0L2Zm1OZfqMWFCrSVD743OFY60YL5CGsN9/PVQP7gApll5yTWyaQJu8lReptR5TMnUDn0u3mJN/QRT5Zs8qS5J5Q3WhXwaMF96kSuu+MwXrBnl8sK+bwxOKQtlKJXowcw==\n"),
+	}
+
+	encoded := c.SSHPublicKeyUrlEncoded()
+
+	decoded, err := url.PathUnescape(encoded)
+	if err != nil {
+		t.Fatal(err.Error())
+	}
+
+	if decoded != string(c.SSHPublicKey) {
+		t.Fatal("resulting public key does not match original public key")
+	}
+}
+
 func testContext(t *testing.T) *interpolate.Context {
 	return nil
 }