diff --git a/vendor/gopkg.in/jcmturner/gokrb5.v7/pac/signature_data.go b/vendor/gopkg.in/jcmturner/gokrb5.v7/pac/signature_data.go
new file mode 100644
index 0000000..7e0fce1
--- /dev/null
+++ b/vendor/gopkg.in/jcmturner/gokrb5.v7/pac/signature_data.go
@@ -0,0 +1,79 @@
+package pac
+
+import (
+	"bytes"
+
+	"gopkg.in/jcmturner/gokrb5.v7/iana/chksumtype"
+	"gopkg.in/jcmturner/rpc.v1/mstypes"
+)
+
+/*
+https://msdn.microsoft.com/en-us/library/cc237955.aspx
+
+The Key Usage Value MUST be KERB_NON_KERB_CKSUM_SALT (17) [MS-KILE] (section 3.1.5.9).
+
+Server Signature (SignatureType = 0x00000006)
+https://msdn.microsoft.com/en-us/library/cc237957.aspx
+The KDC will use the long-term key that the KDC shares with the server, so that the server can verify this signature on receiving a PAC.
+The server signature is a keyed hash [RFC4757] of the entire PAC message, with the Signature fields of both PAC_SIGNATURE_DATA structures set to zero.
+The key used to protect the ciphertext part of the response is used.
+The checksum type corresponds to the key unless the key is DES, in which case the KERB_CHECKSUM_HMAC_MD5 key is used.
+The resulting hash value is then placed in the Signature field of the server's PAC_SIGNATURE_DATA structure.
+
+KDC Signature (SignatureType = 0x00000007)
+https://msdn.microsoft.com/en-us/library/dd357117.aspx
+The KDC will use KDC (krbtgt) key [RFC4120], so that other KDCs can verify this signature on receiving a PAC.
+The KDC signature is a keyed hash [RFC4757] of the Server Signature field in the PAC message.
+The cryptographic system that is used to calculate the checksum depends on which system the KDC supports, as defined below:
+- Supports RC4-HMAC --> KERB_CHECKSUM_HMAC_MD5
+- Does not support RC4-HMAC and supports AES256 --> HMAC_SHA1_96_AES256
+- Does not support RC4-HMAC or AES256-CTS-HMAC-SHA1-96, and supports AES128-CTS-HMAC-SHA1-96 --> HMAC_SHA1_96_AES128
+- Does not support RC4-HMAC, AES128-CTS-HMAC-SHA1-96 or AES256-CTS-HMAC-SHA1-96 -->  None. The checksum operation will fail.
+*/
+
+// SignatureData implements https://msdn.microsoft.com/en-us/library/cc237955.aspx
+type SignatureData struct {
+	SignatureType  uint32 // A 32-bit unsigned integer value in little-endian format that defines the cryptographic system used to calculate the checksum. This MUST be one of the following checksum types: KERB_CHECKSUM_HMAC_MD5 (signature size = 16), HMAC_SHA1_96_AES128 (signature size = 12), HMAC_SHA1_96_AES256 (signature size = 12).
+	Signature      []byte // Size depends on the type. See comment above.
+	RODCIdentifier uint16 // A 16-bit unsigned integer value in little-endian format that contains the first 16 bits of the key version number ([MS-KILE] section 3.1.5.8) when the KDC is an RODC. When the KDC is not an RODC, this field does not exist.
+}
+
+// Unmarshal bytes into the SignatureData struct
+func (k *SignatureData) Unmarshal(b []byte) (rb []byte, err error) {
+	r := mstypes.NewReader(bytes.NewReader(b))
+
+	k.SignatureType, err = r.Uint32()
+	if err != nil {
+		return
+	}
+
+	var c int
+	switch k.SignatureType {
+	case chksumtype.KERB_CHECKSUM_HMAC_MD5_UNSIGNED:
+		c = 16
+	case uint32(chksumtype.HMAC_SHA1_96_AES128):
+		c = 12
+	case uint32(chksumtype.HMAC_SHA1_96_AES256):
+		c = 12
+	}
+	k.Signature, err = r.ReadBytes(c)
+	if err != nil {
+		return
+	}
+
+	// When the KDC is not an Read Only Domain Controller (RODC), this field does not exist.
+	if len(b) >= 4+c+2 {
+		k.RODCIdentifier, err = r.Uint16()
+		if err != nil {
+			return
+		}
+	}
+
+	// Create bytes with zeroed signature needed for checksum verification
+	rb = make([]byte, len(b), len(b))
+	copy(rb, b)
+	z := make([]byte, len(b), len(b))
+	copy(rb[4:4+c], z)
+
+	return
+}