diff --git a/vendor/gopkg.in/jcmturner/rpc.v1/mstypes/sid.go b/vendor/gopkg.in/jcmturner/rpc.v1/mstypes/sid.go
new file mode 100644
index 0000000..98a9c5a
--- /dev/null
+++ b/vendor/gopkg.in/jcmturner/rpc.v1/mstypes/sid.go
@@ -0,0 +1,32 @@
+package mstypes
+
+import (
+	"encoding/binary"
+	"encoding/hex"
+	"fmt"
+)
+
+// RPCSID implements https://msdn.microsoft.com/en-us/library/cc230364.aspx
+type RPCSID struct {
+	Revision            uint8    // An 8-bit unsigned integer that specifies the revision level of the SID. This value MUST be set to 0x01.
+	SubAuthorityCount   uint8    // An 8-bit unsigned integer that specifies the number of elements in the SubAuthority array. The maximum number of elements allowed is 15.
+	IdentifierAuthority [6]byte  // An RPC_SID_IDENTIFIER_AUTHORITY structure that indicates the authority under which the SID was created. It describes the entity that created the SID. The Identifier Authority value {0,0,0,0,0,5} denotes SIDs created by the NT SID authority.
+	SubAuthority        []uint32 `ndr:"conformant"` // A variable length array of unsigned 32-bit integers that uniquely identifies a principal relative to the IdentifierAuthority. Its length is determined by SubAuthorityCount.
+}
+
+// String returns the string representation of the RPC_SID.
+func (s *RPCSID) String() string {
+	var str string
+	b := append(make([]byte, 2, 2), s.IdentifierAuthority[:]...)
+	// For a strange reason this is read big endian: https://msdn.microsoft.com/en-us/library/dd302645.aspx
+	i := binary.BigEndian.Uint64(b)
+	if i >= 4294967296 {
+		str = fmt.Sprintf("S-1-0x%s", hex.EncodeToString(s.IdentifierAuthority[:]))
+	} else {
+		str = fmt.Sprintf("S-1-%d", i)
+	}
+	for _, sub := range s.SubAuthority {
+		str = fmt.Sprintf("%s-%d", str, sub)
+	}
+	return str
+}