diff --git a/vendor/gopkg.in/jcmturner/gokrb5.v7/crypto/rfc3962/keyDerivation.go b/vendor/gopkg.in/jcmturner/gokrb5.v7/crypto/rfc3962/keyDerivation.go
new file mode 100644
index 0000000..a5f45c1
--- /dev/null
+++ b/vendor/gopkg.in/jcmturner/gokrb5.v7/crypto/rfc3962/keyDerivation.go
@@ -0,0 +1,58 @@
+package rfc3962
+
+import (
+	"encoding/binary"
+	"encoding/hex"
+	"errors"
+
+	"github.com/jcmturner/gofork/x/crypto/pbkdf2"
+	"gopkg.in/jcmturner/gokrb5.v7/crypto/etype"
+)
+
+const (
+	s2kParamsZero = 4294967296
+)
+
+// StringToKey returns a key derived from the string provided according to the definition in RFC 3961.
+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)
+}
+
+// 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 int64, e etype.EType) []byte {
+	return pbkdf2.Key64([]byte(secret), []byte(salt), iterations, int64(e.GetKeyByteSize()), e.GetHashFunc())
+}
+
+// StringToKeyIter returns a key derived from the string provided according to the definition in RFC 3961.
+func StringToKeyIter(secret, salt string, iterations int64, e etype.EType) ([]byte, error) {
+	tkey := e.RandomToKey(StringToPBKDF2(secret, salt, iterations, e))
+	return e.DeriveKey(tkey, []byte("kerberos"))
+}
+
+// S2KparamsToItertions converts the string representation of iterations to an integer
+func S2KparamsToItertions(s2kparams string) (int64, error) {
+	//process s2kparams string
+	//The parameter string is four octets indicating an unsigned
+	//number in big-endian order.  This is the number of iterations to be
+	//performed.  If the value is 00 00 00 00, the number of iterations to
+	//be performed is 4,294,967,296 (2**32).
+	var i uint32
+	if len(s2kparams) != 8 {
+		return int64(s2kParamsZero), errors.New("invalid s2kparams length")
+	}
+	b, err := hex.DecodeString(s2kparams)
+	if err != nil {
+		return int64(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 int64(s2kParamsZero), errors.New("invalid s2kparams, cannot convert to big endian int32")
+	}
+	return int64(i), nil
+}