diff --git a/vendor/gopkg.in/jcmturner/gokrb5.v7/crypto/rfc8009/keyDerivation.go b/vendor/gopkg.in/jcmturner/gokrb5.v7/crypto/rfc8009/keyDerivation.go
new file mode 100644
index 0000000..90ced3b
--- /dev/null
+++ b/vendor/gopkg.in/jcmturner/gokrb5.v7/crypto/rfc8009/keyDerivation.go
@@ -0,0 +1,144 @@
+package rfc8009
+
+import (
+	"crypto/hmac"
+	"encoding/binary"
+	"encoding/hex"
+	"errors"
+
+	"golang.org/x/crypto/pbkdf2"
+	"gopkg.in/jcmturner/gokrb5.v7/crypto/etype"
+	"gopkg.in/jcmturner/gokrb5.v7/iana/etypeID"
+)
+
+const (
+	s2kParamsZero = 32768
+)
+
+// DeriveRandom for key derivation as defined in RFC 8009
+func DeriveRandom(protocolKey, usage []byte, e etype.EType) ([]byte, error) {
+	h := e.GetHashFunc()()
+	return KDF_HMAC_SHA2(protocolKey, []byte("prf"), usage, h.Size(), e), nil
+}
+
+// DeriveKey derives a key from the protocol key based on the usage and the etype's specific methods.
+//
+// https://tools.ietf.org/html/rfc8009#section-5
+//
+// If the enctype is aes128-cts-hmac-sha256-128:
+// Kc = KDF-HMAC-SHA2(base-key, usage | 0x99, 128)
+// Ke = KDF-HMAC-SHA2(base-key, usage | 0xAA, 128)
+// Ki = KDF-HMAC-SHA2(base-key, usage | 0x55, 128)
+//
+// If the enctype is aes256-cts-hmac-sha384-192:
+// Kc = KDF-HMAC-SHA2(base-key, usage | 0x99, 192)
+// Ke = KDF-HMAC-SHA2(base-key, usage | 0xAA, 256)
+// Ki = KDF-HMAC-SHA2(base-key, usage | 0x55, 192)
+func DeriveKey(protocolKey, label []byte, e etype.EType) []byte {
+	var context []byte
+	var kl int
+	// Key length is longer for aes256-cts-hmac-sha384-192 is it is a Ke or from StringToKey (where label is "kerberos")
+	if e.GetETypeID() == etypeID.AES256_CTS_HMAC_SHA384_192 {
+		switch label[len(label)-1] {
+		case 0x73:
+			// 0x73 is "s" so label could be kerberos meaning StringToKey so now check if the label is "kerberos"
+			kerblabel := []byte("kerberos")
+			if len(label) != len(kerblabel) {
+				break
+			}
+			for i, b := range label {
+				if b != kerblabel[i] {
+					kl = e.GetKeySeedBitLength()
+					break
+				}
+			}
+			if kl == 0 {
+				// This is StringToKey
+				kl = 256
+			}
+		case 0xAA:
+			// This is a Ke
+			kl = 256
+		}
+	}
+	if kl == 0 {
+		kl = e.GetKeySeedBitLength()
+	}
+	return e.RandomToKey(KDF_HMAC_SHA2(protocolKey, label, context, kl, e))
+}
+
+// RandomToKey returns a key from the bytes provided according to the definition in RFC 8009.
+func RandomToKey(b []byte) []byte {
+	return b
+}
+
+// StringToKey returns a key derived from the string provided according to the definition in RFC 8009.
+func StringToKey(secret, salt, s2kparams string, e etype.EType) ([]byte, error) {
+	i, err := S2KparamsToItertions(s2kparams)
+	if err != nil {
+		return nil, err
+	}
+	return StringToKeyIter(secret, salt, i, e)
+}
+
+// StringToKeyIter returns a key derived from the string provided according to the definition in RFC 8009.
+func StringToKeyIter(secret, salt string, iterations int, e etype.EType) ([]byte, error) {
+	tkey := e.RandomToKey(StringToPBKDF2(secret, salt, iterations, e))
+	return e.DeriveKey(tkey, []byte("kerberos"))
+}
+
+// StringToPBKDF2 generates an encryption key from a pass phrase and salt string using the PBKDF2 function from PKCS #5 v2.0
+func StringToPBKDF2(secret, salt string, iterations int, e etype.EType) []byte {
+	kl := e.GetKeyByteSize()
+	if e.GetETypeID() == etypeID.AES256_CTS_HMAC_SHA384_192 {
+		kl = 32
+	}
+	return pbkdf2.Key([]byte(secret), []byte(salt), iterations, kl, e.GetHashFunc())
+}
+
+// KDF_HMAC_SHA2 key derivation: https://tools.ietf.org/html/rfc8009#section-3
+func KDF_HMAC_SHA2(protocolKey, label, context []byte, kl int, e etype.EType) []byte {
+	//k: Length in bits of the key to be outputted, expressed in big-endian binary representation in 4 bytes.
+	k := make([]byte, 4, 4)
+	binary.BigEndian.PutUint32(k, uint32(kl))
+
+	c := make([]byte, 4, 4)
+	binary.BigEndian.PutUint32(c, uint32(1))
+	c = append(c, label...)
+	c = append(c, byte(0))
+	if len(context) > 0 {
+		c = append(c, context...)
+	}
+	c = append(c, k...)
+
+	mac := hmac.New(e.GetHashFunc(), protocolKey)
+	mac.Write(c)
+	return mac.Sum(nil)[:(kl / 8)]
+}
+
+// GetSaltP returns the salt value based on the etype name: https://tools.ietf.org/html/rfc8009#section-4
+func GetSaltP(salt, ename string) string {
+	b := []byte(ename)
+	b = append(b, byte(0))
+	b = append(b, []byte(salt)...)
+	return string(b)
+}
+
+// S2KparamsToItertions converts the string representation of iterations to an integer for RFC 8009.
+func S2KparamsToItertions(s2kparams string) (int, error) {
+	var i uint32
+	if len(s2kparams) != 8 {
+		return s2kParamsZero, errors.New("Invalid s2kparams length")
+	}
+	b, err := hex.DecodeString(s2kparams)
+	if err != nil {
+		return s2kParamsZero, errors.New("Invalid s2kparams, cannot decode string to bytes")
+	}
+	i = binary.BigEndian.Uint32(b)
+	//buf := bytes.NewBuffer(b)
+	//err = binary.Read(buf, binary.BigEndian, &i)
+	if err != nil {
+		return s2kParamsZero, errors.New("Invalid s2kparams, cannot convert to big endian int32")
+	}
+	return int(i), nil
+}