diff --git a/vendor/gopkg.in/jcmturner/gokrb5.v7/messages/APReq.go b/vendor/gopkg.in/jcmturner/gokrb5.v7/messages/APReq.go
new file mode 100644
index 0000000..e1ed4ae
--- /dev/null
+++ b/vendor/gopkg.in/jcmturner/gokrb5.v7/messages/APReq.go
@@ -0,0 +1,220 @@
+package messages
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/jcmturner/gofork/encoding/asn1"
+	"gopkg.in/jcmturner/gokrb5.v7/asn1tools"
+	"gopkg.in/jcmturner/gokrb5.v7/crypto"
+	"gopkg.in/jcmturner/gokrb5.v7/iana"
+	"gopkg.in/jcmturner/gokrb5.v7/iana/asnAppTag"
+	"gopkg.in/jcmturner/gokrb5.v7/iana/errorcode"
+	"gopkg.in/jcmturner/gokrb5.v7/iana/keyusage"
+	"gopkg.in/jcmturner/gokrb5.v7/iana/msgtype"
+	"gopkg.in/jcmturner/gokrb5.v7/keytab"
+	"gopkg.in/jcmturner/gokrb5.v7/krberror"
+	"gopkg.in/jcmturner/gokrb5.v7/types"
+)
+
+/*AP-REQ          ::= [APPLICATION 14] SEQUENCE {
+pvno            [0] INTEGER (5),
+msg-type        [1] INTEGER (14),
+ap-options      [2] APOptions,
+ticket          [3] Ticket,
+authenticator   [4] EncryptedData -- Authenticator
+}
+
+APOptions       ::= KerberosFlags
+-- reserved(0),
+-- use-session-key(1),
+-- mutual-required(2)*/
+
+type marshalAPReq struct {
+	PVNO      int            `asn1:"explicit,tag:0"`
+	MsgType   int            `asn1:"explicit,tag:1"`
+	APOptions asn1.BitString `asn1:"explicit,tag:2"`
+	// Ticket needs to be a raw value as it is wrapped in an APPLICATION tag
+	Ticket                 asn1.RawValue       `asn1:"explicit,tag:3"`
+	EncryptedAuthenticator types.EncryptedData `asn1:"explicit,tag:4"`
+}
+
+// APReq implements RFC 4120 KRB_AP_REQ: https://tools.ietf.org/html/rfc4120#section-5.5.1.
+type APReq struct {
+	PVNO                   int                 `asn1:"explicit,tag:0"`
+	MsgType                int                 `asn1:"explicit,tag:1"`
+	APOptions              asn1.BitString      `asn1:"explicit,tag:2"`
+	Ticket                 Ticket              `asn1:"explicit,tag:3"`
+	EncryptedAuthenticator types.EncryptedData `asn1:"explicit,tag:4"`
+	Authenticator          types.Authenticator `asn1:"optional"`
+}
+
+// NewAPReq generates a new KRB_AP_REQ struct.
+func NewAPReq(tkt Ticket, sessionKey types.EncryptionKey, auth types.Authenticator) (APReq, error) {
+	var a APReq
+	ed, err := encryptAuthenticator(auth, sessionKey, tkt)
+	if err != nil {
+		return a, krberror.Errorf(err, krberror.KRBMsgError, "error creating Authenticator for AP_REQ")
+	}
+	a = APReq{
+		PVNO:                   iana.PVNO,
+		MsgType:                msgtype.KRB_AP_REQ,
+		APOptions:              types.NewKrbFlags(),
+		Ticket:                 tkt,
+		EncryptedAuthenticator: ed,
+	}
+	return a, nil
+}
+
+// Encrypt Authenticator
+func encryptAuthenticator(a types.Authenticator, sessionKey types.EncryptionKey, tkt Ticket) (types.EncryptedData, error) {
+	var ed types.EncryptedData
+	m, err := a.Marshal()
+	if err != nil {
+		return ed, krberror.Errorf(err, krberror.EncodingError, "marshaling error of EncryptedData form of Authenticator")
+	}
+	usage := authenticatorKeyUsage(tkt.SName)
+	ed, err = crypto.GetEncryptedData(m, sessionKey, uint32(usage), tkt.EncPart.KVNO)
+	if err != nil {
+		return ed, krberror.Errorf(err, krberror.EncryptingError, "error encrypting Authenticator")
+	}
+	return ed, nil
+}
+
+// DecryptAuthenticator decrypts the Authenticator within the AP_REQ.
+// sessionKey may simply be the key within the decrypted EncPart of the ticket within the AP_REQ.
+func (a *APReq) DecryptAuthenticator(sessionKey types.EncryptionKey) error {
+	usage := authenticatorKeyUsage(a.Ticket.SName)
+	ab, e := crypto.DecryptEncPart(a.EncryptedAuthenticator, sessionKey, uint32(usage))
+	if e != nil {
+		return fmt.Errorf("error decrypting authenticator: %v", e)
+	}
+	err := a.Authenticator.Unmarshal(ab)
+	if err != nil {
+		return fmt.Errorf("error unmarshaling authenticator: %v", err)
+	}
+	return nil
+}
+
+func authenticatorKeyUsage(pn types.PrincipalName) int {
+	if pn.NameString[0] == "krbtgt" {
+		return keyusage.TGS_REQ_PA_TGS_REQ_AP_REQ_AUTHENTICATOR
+	}
+	return keyusage.AP_REQ_AUTHENTICATOR
+}
+
+// Unmarshal bytes b into the APReq struct.
+func (a *APReq) Unmarshal(b []byte) error {
+	var m marshalAPReq
+	_, err := asn1.UnmarshalWithParams(b, &m, fmt.Sprintf("application,explicit,tag:%v", asnAppTag.APREQ))
+	if err != nil {
+		return krberror.Errorf(err, krberror.EncodingError, "unmarshal error of AP_REQ")
+	}
+	if m.MsgType != msgtype.KRB_AP_REQ {
+		return NewKRBError(types.PrincipalName{}, "", errorcode.KRB_AP_ERR_MSG_TYPE, errorcode.Lookup(errorcode.KRB_AP_ERR_MSG_TYPE))
+	}
+	a.PVNO = m.PVNO
+	a.MsgType = m.MsgType
+	a.APOptions = m.APOptions
+	a.EncryptedAuthenticator = m.EncryptedAuthenticator
+	a.Ticket, err = unmarshalTicket(m.Ticket.Bytes)
+	if err != nil {
+		return krberror.Errorf(err, krberror.EncodingError, "unmarshaling error of Ticket within AP_REQ")
+	}
+	return nil
+}
+
+// Marshal APReq struct.
+func (a *APReq) Marshal() ([]byte, error) {
+	m := marshalAPReq{
+		PVNO:                   a.PVNO,
+		MsgType:                a.MsgType,
+		APOptions:              a.APOptions,
+		EncryptedAuthenticator: a.EncryptedAuthenticator,
+	}
+	var b []byte
+	b, err := a.Ticket.Marshal()
+	if err != nil {
+		return b, err
+	}
+	m.Ticket = asn1.RawValue{
+		Class:      asn1.ClassContextSpecific,
+		IsCompound: true,
+		Tag:        3,
+		Bytes:      b,
+	}
+	mk, err := asn1.Marshal(m)
+	if err != nil {
+		return mk, krberror.Errorf(err, krberror.EncodingError, "marshaling error of AP_REQ")
+	}
+	mk = asn1tools.AddASNAppTag(mk, asnAppTag.APREQ)
+	return mk, nil
+}
+
+// Verify an AP_REQ using service's keytab, spn and max acceptable clock skew duration.
+// The service ticket encrypted part and authenticator will be decrypted as part of this operation.
+func (a *APReq) Verify(kt *keytab.Keytab, d time.Duration, cAddr types.HostAddress) (bool, error) {
+	// Decrypt ticket's encrypted part with service key
+	//TODO decrypt with service's session key from its TGT is use-to-user. Need to figure out how to get TGT.
+	//if types.IsFlagSet(&a.APOptions, flags.APOptionUseSessionKey) {
+	//	//If the USE-SESSION-KEY flag is set in the ap-options field, it indicates to
+	//	//the server that user-to-user authentication is in use, and that the ticket
+	//	//is encrypted in the session key from the server's TGT rather than in the server's secret key.
+	//	err := a.Ticket.Decrypt(tgt.DecryptedEncPart.Key)
+	//	if err != nil {
+	//		return false, krberror.Errorf(err, krberror.DecryptingError, "error decrypting encpart of ticket provided using session key")
+	//	}
+	//} else {
+	//	// Because it is possible for the server to be registered in multiple
+	//	// realms, with different keys in each, the srealm field in the
+	//	// unencrypted portion of the ticket in the KRB_AP_REQ is used to
+	//	// specify which secret key the server should use to decrypt that
+	//	// ticket.The KRB_AP_ERR_NOKEY error code is returned if the server
+	//	// doesn't have the proper key to decipher the ticket.
+	//	// The ticket is decrypted using the version of the server's key
+	//	// specified by the ticket.
+	//	err := a.Ticket.DecryptEncPart(*kt, &a.Ticket.SName)
+	//	if err != nil {
+	//		return false, krberror.Errorf(err, krberror.DecryptingError, "error decrypting encpart of service ticket provided")
+	//	}
+	//}
+	err := a.Ticket.DecryptEncPart(kt, &a.Ticket.SName)
+	if err != nil {
+		return false, krberror.Errorf(err, krberror.DecryptingError, "error decrypting encpart of service ticket provided")
+	}
+
+	// Check time validity of ticket
+	ok, err := a.Ticket.Valid(d)
+	if err != nil || !ok {
+		return ok, err
+	}
+
+	// Check client's address is listed in the client addresses in the ticket
+	if len(a.Ticket.DecryptedEncPart.CAddr) > 0 {
+		//The addresses in the ticket (if any) are then searched for an address matching the operating-system reported
+		//address of the client.  If no match is found or the server insists on ticket addresses but none are present in
+		//the ticket, the KRB_AP_ERR_BADADDR error is returned.
+		if !types.HostAddressesContains(a.Ticket.DecryptedEncPart.CAddr, cAddr) {
+			return false, NewKRBError(a.Ticket.SName, a.Ticket.Realm, errorcode.KRB_AP_ERR_BADADDR, "client address not within the list contained in the service ticket")
+		}
+	}
+
+	// Decrypt authenticator with session key from ticket's encrypted part
+	err = a.DecryptAuthenticator(a.Ticket.DecryptedEncPart.Key)
+	if err != nil {
+		return false, NewKRBError(a.Ticket.SName, a.Ticket.Realm, errorcode.KRB_AP_ERR_BAD_INTEGRITY, "could not decrypt authenticator")
+	}
+
+	// Check CName in authenticator is the same as that in the ticket
+	if !a.Authenticator.CName.Equal(a.Ticket.DecryptedEncPart.CName) {
+		return false, NewKRBError(a.Ticket.SName, a.Ticket.Realm, errorcode.KRB_AP_ERR_BADMATCH, "CName in Authenticator does not match that in service ticket")
+	}
+
+	// Check the clock skew between the client and the service server
+	ct := a.Authenticator.CTime.Add(time.Duration(a.Authenticator.Cusec) * time.Microsecond)
+	t := time.Now().UTC()
+	if t.Sub(ct) > d || ct.Sub(t) > d {
+		return false, NewKRBError(a.Ticket.SName, a.Ticket.Realm, errorcode.KRB_AP_ERR_SKEW, fmt.Sprintf("clock skew with client too large. greater than %v seconds", d))
+	}
+	return true, nil
+}