diff --git a/client/client.go b/client/client.go
index 245a4029a19057765f53d11a254dea33da140855..3aa4e5bbb5c1b4261209196a7ea94da6d8e2220a 100644
--- a/client/client.go
+++ b/client/client.go
@@ -1,9 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"io"
 	"net/textproto"
 
 	"git.autistici.org/id/auth"
@@ -47,11 +45,8 @@ func (c *socketClient) Authenticate(ctx context.Context, req *auth.Request) (*au
 	go func() {
 		defer close(done)
 
-		// Write the command to a buffer.
-		var buf bytes.Buffer
-		io.WriteString(&buf, "auth ")
-		buf.Write(c.codec.Encode(req))
-		if err := conn.PrintfLine(buf.String()); err != nil {
+		// Write the auth command to the connection.
+		if err := conn.PrintfLine("auth %s", string(c.codec.Encode(req))); err != nil {
 			done <- err
 			return
 		}