diff --git a/vendor/gopkg.in/jcmturner/gokrb5.v7/crypto/common/common.go b/vendor/gopkg.in/jcmturner/gokrb5.v7/crypto/common/common.go
new file mode 100644
index 0000000..96ae549
--- /dev/null
+++ b/vendor/gopkg.in/jcmturner/gokrb5.v7/crypto/common/common.go
@@ -0,0 +1,143 @@
+// Package common provides encryption methods common across encryption types
+package common
+
+import (
+	"bytes"
+	"crypto/hmac"
+	"encoding/binary"
+	"encoding/hex"
+	"errors"
+	"fmt"
+
+	"gopkg.in/jcmturner/gokrb5.v7/crypto/etype"
+)
+
+// ZeroPad pads bytes with zeros to nearest multiple of message size m.
+func ZeroPad(b []byte, m int) ([]byte, error) {
+	if m <= 0 {
+		return nil, errors.New("Invalid message block size when padding")
+	}
+	if b == nil || len(b) == 0 {
+		return nil, errors.New("Data not valid to pad: Zero size")
+	}
+	if l := len(b) % m; l != 0 {
+		n := m - l
+		z := make([]byte, n)
+		b = append(b, z...)
+	}
+	return b, nil
+}
+
+// PKCS7Pad pads bytes according to RFC 2315 to nearest multiple of message size m.
+func PKCS7Pad(b []byte, m int) ([]byte, error) {
+	if m <= 0 {
+		return nil, errors.New("Invalid message block size when padding")
+	}
+	if b == nil || len(b) == 0 {
+		return nil, errors.New("Data not valid to pad: Zero size")
+	}
+	n := m - (len(b) % m)
+	pb := make([]byte, len(b)+n)
+	copy(pb, b)
+	copy(pb[len(b):], bytes.Repeat([]byte{byte(n)}, n))
+	return pb, nil
+}
+
+// PKCS7Unpad removes RFC 2315 padding from byes where message size is m.
+func PKCS7Unpad(b []byte, m int) ([]byte, error) {
+	if m <= 0 {
+		return nil, errors.New("invalid message block size when unpadding")
+	}
+	if b == nil || len(b) == 0 {
+		return nil, errors.New("padded data not valid: Zero size")
+	}
+	if len(b)%m != 0 {
+		return nil, errors.New("padded data not valid: Not multiple of message block size")
+	}
+	c := b[len(b)-1]
+	n := int(c)
+	if n == 0 || n > len(b) {
+		return nil, errors.New("padded data not valid: Data may not have been padded")
+	}
+	for i := 0; i < n; i++ {
+		if b[len(b)-n+i] != c {
+			return nil, errors.New("padded data not valid")
+		}
+	}
+	return b[:len(b)-n], nil
+}
+
+// GetHash generates the keyed hash value according to the etype's hash function.
+func GetHash(pt, key []byte, usage []byte, etype etype.EType) ([]byte, error) {
+	k, err := etype.DeriveKey(key, usage)
+	if err != nil {
+		return nil, fmt.Errorf("unable to derive key for checksum: %v", err)
+	}
+	mac := hmac.New(etype.GetHashFunc(), k)
+	p := make([]byte, len(pt))
+	copy(p, pt)
+	mac.Write(p)
+	return mac.Sum(nil)[:etype.GetHMACBitLength()/8], nil
+}
+
+// GetChecksumHash returns a keyed checksum hash of the bytes provided.
+func GetChecksumHash(b, key []byte, usage uint32, etype etype.EType) ([]byte, error) {
+	return GetHash(b, key, GetUsageKc(usage), etype)
+}
+
+// GetIntegrityHash returns a keyed integrity hash of the bytes provided.
+func GetIntegrityHash(b, key []byte, usage uint32, etype etype.EType) ([]byte, error) {
+	return GetHash(b, key, GetUsageKi(usage), etype)
+}
+
+// VerifyChecksum compares the checksum of the msg bytes is the same as the checksum provided.
+func VerifyChecksum(key, chksum, msg []byte, usage uint32, etype etype.EType) bool {
+	//The ciphertext output is the concatenation of the output of the basic
+	//encryption function E and a (possibly truncated) HMAC using the
+	//specified hash function H, both applied to the plaintext with a
+	//random confounder prefix and sufficient padding to bring it to a
+	//multiple of the message block size.  When the HMAC is computed, the
+	//key is used in the protocol key form.
+	expectedMAC, _ := GetChecksumHash(msg, key, usage, etype)
+	return hmac.Equal(chksum, expectedMAC)
+}
+
+// GetUsageKc returns the checksum key usage value for the usage number un.
+//
+// RFC 3961: The "well-known constant" used for the DK function is the key usage number, expressed as four octets in big-endian order, followed by one octet indicated below.
+//
+// Kc = DK(base-key, usage | 0x99);
+func GetUsageKc(un uint32) []byte {
+	return getUsage(un, 0x99)
+}
+
+// GetUsageKe returns the encryption key usage value for the usage number un
+//
+// RFC 3961: The "well-known constant" used for the DK function is the key usage number, expressed as four octets in big-endian order, followed by one octet indicated below.
+//
+// Ke = DK(base-key, usage | 0xAA);
+func GetUsageKe(un uint32) []byte {
+	return getUsage(un, 0xAA)
+}
+
+// GetUsageKi returns the integrity key usage value for the usage number un
+//
+// RFC 3961: The "well-known constant" used for the DK function is the key usage number, expressed as four octets in big-endian order, followed by one octet indicated below.
+//
+// Ki = DK(base-key, usage | 0x55);
+func GetUsageKi(un uint32) []byte {
+	return getUsage(un, 0x55)
+}
+
+func getUsage(un uint32, o byte) []byte {
+	var buf bytes.Buffer
+	binary.Write(&buf, binary.BigEndian, un)
+	return append(buf.Bytes(), o)
+}
+
+// IterationsToS2Kparams converts the number of iterations as an integer to a string representation.
+func IterationsToS2Kparams(i uint32) string {
+	b := make([]byte, 4, 4)
+	binary.BigEndian.PutUint32(b, i)
+	return hex.EncodeToString(b)
+}