diff --git a/vendor/gopkg.in/jcmturner/gokrb5.v7/gssapi/wrapToken.go b/vendor/gopkg.in/jcmturner/gokrb5.v7/gssapi/wrapToken.go
new file mode 100644
index 0000000..9dbf96b
--- /dev/null
+++ b/vendor/gopkg.in/jcmturner/gokrb5.v7/gssapi/wrapToken.go
@@ -0,0 +1,235 @@
+package gssapi
+
+import (
+	"bytes"
+	"crypto/hmac"
+	"encoding/binary"
+	"encoding/hex"
+	"errors"
+	"fmt"
+
+	"gopkg.in/jcmturner/gokrb5.v7/crypto"
+	"gopkg.in/jcmturner/gokrb5.v7/iana/keyusage"
+	"gopkg.in/jcmturner/gokrb5.v7/types"
+)
+
+/*
+From RFC 4121, section 4.2.6.2:
+
+   Use of the GSS_Wrap() call yields a token (referred as the Wrap token
+   in this document), which consists of a descriptive header, followed
+   by a body portion that contains either the input user data in
+   plaintext concatenated with the checksum, or the input user data
+   encrypted.  The GSS_Wrap() token SHALL have the following format:
+
+         Octet no   Name        Description
+         --------------------------------------------------------------
+          0..1     TOK_ID    Identification field.  Tokens emitted by
+                             GSS_Wrap() contain the hex value 05 04
+                             expressed in big-endian order in this
+                             field.
+          2        Flags     Attributes field, as described in section
+                             4.2.2.
+          3        Filler    Contains the hex value FF.
+          4..5     EC        Contains the "extra count" field, in big-
+                             endian order as described in section 4.2.3.
+          6..7     RRC       Contains the "right rotation count" in big-
+                             endian order, as described in section
+                             4.2.5.
+          8..15    SndSeqNum   Sequence number field in clear text,
+                             expressed in big-endian order.
+          16..last Data      Encrypted data for Wrap tokens with
+                             confidentiality, or plaintext data followed
+                             by the checksum for Wrap tokens without
+                             confidentiality, as described in section
+                             4.2.4.
+
+Quick notes:
+	- "EC" or "Extra Count" refers to the length of the checksum.
+	- "Flags" (complete details in section 4.2.2) is a set of bits:
+		- if bit 0 is set, it means the token was sent by the acceptor (generally the kerberized service).
+		- bit 1 indicates that the token's payload is encrypted
+ 		- bit 2 indicates if the message is protected using a subkey defined by the acceptor.
+	- When computing checksums, EC and RRC MUST be set to 0.
+    - Wrap Tokens are not ASN.1 encoded.
+*/
+const (
+	HdrLen          = 16 // Length of the Wrap Token's header
+	FillerByte byte = 0xFF
+)
+
+// WrapToken represents a GSS API Wrap token, as defined in RFC 4121.
+// It contains the header fields, the payload and the checksum, and provides
+// the logic for converting to/from bytes plus computing and verifying checksums
+type WrapToken struct {
+	// const GSS Token ID: 0x0504
+	Flags byte // contains three flags: acceptor, sealed, acceptor subkey
+	// const Filler: 0xFF
+	EC        uint16 // checksum length. big-endian
+	RRC       uint16 // right rotation count. big-endian
+	SndSeqNum uint64 // sender's sequence number. big-endian
+	Payload   []byte // your data! :)
+	CheckSum  []byte // authenticated checksum of { payload | header }
+}
+
+// Return the 2 bytes identifying a GSS API Wrap token
+func getGssWrapTokenId() *[2]byte {
+	return &[2]byte{0x05, 0x04}
+}
+
+// Marshal the WrapToken into a byte slice.
+// The payload should have been set and the checksum computed, otherwise an error is returned.
+func (wt *WrapToken) Marshal() ([]byte, error) {
+	if wt.CheckSum == nil {
+		return nil, errors.New("checksum has not been set")
+	}
+	if wt.Payload == nil {
+		return nil, errors.New("payload has not been set")
+	}
+
+	pldOffset := HdrLen                    // Offset of the payload in the token
+	chkSOffset := HdrLen + len(wt.Payload) // Offset of the checksum in the token
+
+	bytes := make([]byte, chkSOffset+int(wt.EC))
+	copy(bytes[0:], getGssWrapTokenId()[:])
+	bytes[2] = wt.Flags
+	bytes[3] = FillerByte
+	binary.BigEndian.PutUint16(bytes[4:6], wt.EC)
+	binary.BigEndian.PutUint16(bytes[6:8], wt.RRC)
+	binary.BigEndian.PutUint64(bytes[8:16], wt.SndSeqNum)
+	copy(bytes[pldOffset:], wt.Payload)
+	copy(bytes[chkSOffset:], wt.CheckSum)
+	return bytes, nil
+}
+
+// SetCheckSum uses the passed encryption key and key usage to compute the checksum over the payload and
+// the header, and sets the CheckSum field of this WrapToken.
+// If the payload has not been set or the checksum has already been set, an error is returned.
+func (wt *WrapToken) SetCheckSum(key types.EncryptionKey, keyUsage uint32) error {
+	if wt.Payload == nil {
+		return errors.New("payload has not been set")
+	}
+	if wt.CheckSum != nil {
+		return errors.New("checksum has already been computed")
+	}
+	chkSum, cErr := wt.computeCheckSum(key, keyUsage)
+	if cErr != nil {
+		return cErr
+	}
+	wt.CheckSum = chkSum
+	return nil
+}
+
+// ComputeCheckSum computes and returns the checksum of this token, computed using the passed key and key usage.
+// Conforms to RFC 4121 in that the checksum will be computed over { body | header },
+// with the EC and RRC flags zeroed out.
+// In the context of Kerberos Wrap tokens, mostly keyusage GSSAPI_ACCEPTOR_SEAL (=22)
+// and GSSAPI_INITIATOR_SEAL (=24) will be used.
+// Note: This will NOT update the struct's Checksum field.
+func (wt *WrapToken) computeCheckSum(key types.EncryptionKey, keyUsage uint32) ([]byte, error) {
+	if wt.Payload == nil {
+		return nil, errors.New("cannot compute checksum with uninitialized payload")
+	}
+	// Build a slice containing { payload | header }
+	checksumMe := make([]byte, HdrLen+len(wt.Payload))
+	copy(checksumMe[0:], wt.Payload)
+	copy(checksumMe[len(wt.Payload):], getChecksumHeader(wt.Flags, wt.SndSeqNum))
+
+	encType, err := crypto.GetEtype(key.KeyType)
+	if err != nil {
+		return nil, err
+	}
+	return encType.GetChecksumHash(key.KeyValue, checksumMe, keyUsage)
+}
+
+// Build a header suitable for a checksum computation
+func getChecksumHeader(flags byte, senderSeqNum uint64) []byte {
+	header := make([]byte, 16)
+	copy(header[0:], []byte{0x05, 0x04, flags, 0xFF, 0x00, 0x00, 0x00, 0x00})
+	binary.BigEndian.PutUint64(header[8:], senderSeqNum)
+	return header
+}
+
+// Verify computes the token's checksum with the provided key and usage,
+// and compares it to the checksum present in the token.
+// In case of any failure, (false, Err) is returned, with Err an explanatory error.
+func (wt *WrapToken) Verify(key types.EncryptionKey, keyUsage uint32) (bool, error) {
+	computed, cErr := wt.computeCheckSum(key, keyUsage)
+	if cErr != nil {
+		return false, cErr
+	}
+	if !hmac.Equal(computed, wt.CheckSum) {
+		return false, fmt.Errorf(
+			"checksum mismatch. Computed: %s, Contained in token: %s",
+			hex.EncodeToString(computed), hex.EncodeToString(wt.CheckSum))
+	}
+	return true, nil
+}
+
+// Unmarshal bytes into the corresponding WrapToken.
+// If expectFromAcceptor is true, we expect the token to have been emitted by the gss acceptor,
+// and will check the according flag, returning an error if the token does not match the expectation.
+func (wt *WrapToken) Unmarshal(b []byte, expectFromAcceptor bool) error {
+	// Check if we can read a whole header
+	if len(b) < 16 {
+		return errors.New("bytes shorter than header length")
+	}
+	// Is the Token ID correct?
+	if !bytes.Equal(getGssWrapTokenId()[:], b[0:2]) {
+		return fmt.Errorf("wrong Token ID. Expected %s, was %s",
+			hex.EncodeToString(getGssWrapTokenId()[:]),
+			hex.EncodeToString(b[0:2]))
+	}
+	// Check the acceptor flag
+	flags := b[2]
+	isFromAcceptor := flags&0x01 == 1
+	if isFromAcceptor && !expectFromAcceptor {
+		return errors.New("unexpected acceptor flag is set: not expecting a token from the acceptor")
+	}
+	if !isFromAcceptor && expectFromAcceptor {
+		return errors.New("expected acceptor flag is not set: expecting a token from the acceptor, not the initiator")
+	}
+	// Check the filler byte
+	if b[3] != FillerByte {
+		return fmt.Errorf("unexpected filler byte: expecting 0xFF, was %s ", hex.EncodeToString(b[3:4]))
+	}
+	checksumL := binary.BigEndian.Uint16(b[4:6])
+	// Sanity check on the checksum length
+	if int(checksumL) > len(b)-HdrLen {
+		return fmt.Errorf("inconsistent checksum length: %d bytes to parse, checksum length is %d", len(b), checksumL)
+	}
+
+	wt.Flags = flags
+	wt.EC = checksumL
+	wt.RRC = binary.BigEndian.Uint16(b[6:8])
+	wt.SndSeqNum = binary.BigEndian.Uint64(b[8:16])
+	wt.Payload = b[16 : len(b)-int(checksumL)]
+	wt.CheckSum = b[len(b)-int(checksumL):]
+	return nil
+}
+
+// NewInitiatorWrapToken builds a new initiator token (acceptor flag will be set to 0) and computes the authenticated checksum.
+// Other flags are set to 0, and the RRC and sequence number are initialized to 0.
+// Note that in certain circumstances you may need to provide a sequence number that has been defined earlier.
+// This is currently not supported.
+func NewInitiatorWrapToken(payload []byte, key types.EncryptionKey) (*WrapToken, error) {
+	encType, err := crypto.GetEtype(key.KeyType)
+	if err != nil {
+		return nil, err
+	}
+
+	token := WrapToken{
+		Flags: 0x00, // all zeroed out (this is a token sent by the initiator)
+		// Checksum size: length of output of the HMAC function, in bytes.
+		EC:        uint16(encType.GetHMACBitLength() / 8),
+		RRC:       0,
+		SndSeqNum: 0,
+		Payload:   payload,
+	}
+
+	if err := token.SetCheckSum(key, keyusage.GSSAPI_INITIATOR_SEAL); err != nil {
+		return nil, err
+	}
+
+	return &token, nil
+}