diff --git a/vendor/github.com/xdg/scram/scram.go b/vendor/github.com/xdg/scram/scram.go
new file mode 100644
index 0000000..9e9836a
--- /dev/null
+++ b/vendor/github.com/xdg/scram/scram.go
@@ -0,0 +1,66 @@
+// Copyright 2018 by David A. Golden. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may
+// not use this file except in compliance with the License. You may obtain
+// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
+
+package scram
+
+import (
+	"crypto/sha1"
+	"crypto/sha256"
+	"fmt"
+	"hash"
+
+	"github.com/xdg/stringprep"
+)
+
+// HashGeneratorFcn abstracts a factory function that returns a hash.Hash
+// value to be used for SCRAM operations.  Generally, one would use the
+// provided package variables, `scram.SHA1` and `scram.SHA256`, for the most
+// common forms of SCRAM.
+type HashGeneratorFcn func() hash.Hash
+
+// SHA1 is a function that returns a crypto/sha1 hasher and should be used to
+// create Client objects configured for SHA-1 hashing.
+var SHA1 HashGeneratorFcn = func() hash.Hash { return sha1.New() }
+
+// SHA256 is a function that returns a crypto/sha256 hasher and should be used
+// to create Client objects configured for SHA-256 hashing.
+var SHA256 HashGeneratorFcn = func() hash.Hash { return sha256.New() }
+
+// NewClient constructs a SCRAM client component based on a given hash.Hash
+// factory receiver.  This constructor will normalize the username, password
+// and authzID via the SASLprep algorithm, as recommended by RFC-5802.  If
+// SASLprep fails, the method returns an error.
+func (f HashGeneratorFcn) NewClient(username, password, authzID string) (*Client, error) {
+	var userprep, passprep, authprep string
+	var err error
+
+	if userprep, err = stringprep.SASLprep.Prepare(username); err != nil {
+		return nil, fmt.Errorf("Error SASLprepping username '%s': %v", username, err)
+	}
+	if passprep, err = stringprep.SASLprep.Prepare(password); err != nil {
+		return nil, fmt.Errorf("Error SASLprepping password '%s': %v", password, err)
+	}
+	if authprep, err = stringprep.SASLprep.Prepare(authzID); err != nil {
+		return nil, fmt.Errorf("Error SASLprepping authzID '%s': %v", authzID, err)
+	}
+
+	return newClient(userprep, passprep, authprep, f), nil
+}
+
+// NewClientUnprepped acts like NewClient, except none of the arguments will
+// be normalized via SASLprep.  This is not generally recommended, but is
+// provided for users that may have custom normalization needs.
+func (f HashGeneratorFcn) NewClientUnprepped(username, password, authzID string) (*Client, error) {
+	return newClient(username, password, authzID, f), nil
+}
+
+// NewServer constructs a SCRAM server component based on a given hash.Hash
+// factory receiver.  To be maximally generic, it uses dependency injection to
+// handle credential lookup, which is the process of turning a username string
+// into a struct with stored credentials for authentication.
+func (f HashGeneratorFcn) NewServer(cl CredentialLookup) (*Server, error) {
+	return newServer(cl, f)
+}