diff --git a/vendor/github.com/grpc-ecosystem/go-grpc-middleware/util/metautils/nicemd.go b/vendor/github.com/grpc-ecosystem/go-grpc-middleware/util/metautils/nicemd.go
index a277bee..1c60585 100644
--- a/vendor/github.com/grpc-ecosystem/go-grpc-middleware/util/metautils/nicemd.go
+++ b/vendor/github.com/grpc-ecosystem/go-grpc-middleware/util/metautils/nicemd.go
@@ -4,9 +4,9 @@
 package metautils
 
 import (
+	"context"
 	"strings"
 
-	"golang.org/x/net/context"
 	"google.golang.org/grpc/metadata"
 )
 
@@ -49,7 +49,7 @@
 			found = true
 		} else {
 			for _, allowedKey := range copiedKeys {
-				if strings.ToLower(allowedKey) == strings.ToLower(k) {
+				if strings.EqualFold(allowedKey, k) {
 					found = true
 					break
 				}
@@ -83,7 +83,7 @@
 //
 // The function is binary-key safe.
 func (m NiceMD) Get(key string) string {
-	k, _ := encodeKeyValue(key, "")
+	k := strings.ToLower(key)
 	vv, ok := m[k]
 	if !ok {
 		return ""
@@ -98,7 +98,7 @@
 // The function is binary-key safe.
 
 func (m NiceMD) Del(key string) NiceMD {
-	k, _ := encodeKeyValue(key, "")
+	k := strings.ToLower(key)
 	delete(m, k)
 	return m
 }
@@ -109,8 +109,8 @@
 //
 // The function is binary-key safe.
 func (m NiceMD) Set(key string, value string) NiceMD {
-	k, v := encodeKeyValue(key, value)
-	m[k] = []string{v}
+	k := strings.ToLower(key)
+	m[k] = []string{value}
 	return m
 }
 
@@ -120,7 +120,7 @@
 //
 // The function is binary-key safe.
 func (m NiceMD) Add(key string, value string) NiceMD {
-	k, v := encodeKeyValue(key, value)
-	m[k] = append(m[k], v)
+	k := strings.ToLower(key)
+	m[k] = append(m[k], value)
 	return m
 }
diff --git a/vendor/github.com/grpc-ecosystem/go-grpc-middleware/util/metautils/single_key.go b/vendor/github.com/grpc-ecosystem/go-grpc-middleware/util/metautils/single_key.go
deleted file mode 100644
index 8a53871..0000000
--- a/vendor/github.com/grpc-ecosystem/go-grpc-middleware/util/metautils/single_key.go
+++ /dev/null
@@ -1,22 +0,0 @@
-// Copyright 2016 Michal Witkowski. All Rights Reserved.
-// See LICENSE for licensing terms.
-
-package metautils
-
-import (
-	"encoding/base64"
-	"strings"
-)
-
-const (
-	binHdrSuffix = "-bin"
-)
-
-func encodeKeyValue(k, v string) (string, string) {
-	k = strings.ToLower(k)
-	if strings.HasSuffix(k, binHdrSuffix) {
-		val := base64.StdEncoding.EncodeToString([]byte(v))
-		v = string(val)
-	}
-	return k, v
-}