diff --git a/vendor/golang.org/x/crypto/md4/md4block.go b/vendor/golang.org/x/crypto/md4/md4block.go
new file mode 100644
index 0000000..3fed475
--- /dev/null
+++ b/vendor/golang.org/x/crypto/md4/md4block.go
@@ -0,0 +1,89 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// MD4 block step.
+// In its own file so that a faster assembly or C version
+// can be substituted easily.
+
+package md4
+
+var shift1 = []uint{3, 7, 11, 19}
+var shift2 = []uint{3, 5, 9, 13}
+var shift3 = []uint{3, 9, 11, 15}
+
+var xIndex2 = []uint{0, 4, 8, 12, 1, 5, 9, 13, 2, 6, 10, 14, 3, 7, 11, 15}
+var xIndex3 = []uint{0, 8, 4, 12, 2, 10, 6, 14, 1, 9, 5, 13, 3, 11, 7, 15}
+
+func _Block(dig *digest, p []byte) int {
+	a := dig.s[0]
+	b := dig.s[1]
+	c := dig.s[2]
+	d := dig.s[3]
+	n := 0
+	var X [16]uint32
+	for len(p) >= _Chunk {
+		aa, bb, cc, dd := a, b, c, d
+
+		j := 0
+		for i := 0; i < 16; i++ {
+			X[i] = uint32(p[j]) | uint32(p[j+1])<<8 | uint32(p[j+2])<<16 | uint32(p[j+3])<<24
+			j += 4
+		}
+
+		// If this needs to be made faster in the future,
+		// the usual trick is to unroll each of these
+		// loops by a factor of 4; that lets you replace
+		// the shift[] lookups with constants and,
+		// with suitable variable renaming in each
+		// unrolled body, delete the a, b, c, d = d, a, b, c
+		// (or you can let the optimizer do the renaming).
+		//
+		// The index variables are uint so that % by a power
+		// of two can be optimized easily by a compiler.
+
+		// Round 1.
+		for i := uint(0); i < 16; i++ {
+			x := i
+			s := shift1[i%4]
+			f := ((c ^ d) & b) ^ d
+			a += f + X[x]
+			a = a<<s | a>>(32-s)
+			a, b, c, d = d, a, b, c
+		}
+
+		// Round 2.
+		for i := uint(0); i < 16; i++ {
+			x := xIndex2[i]
+			s := shift2[i%4]
+			g := (b & c) | (b & d) | (c & d)
+			a += g + X[x] + 0x5a827999
+			a = a<<s | a>>(32-s)
+			a, b, c, d = d, a, b, c
+		}
+
+		// Round 3.
+		for i := uint(0); i < 16; i++ {
+			x := xIndex3[i]
+			s := shift3[i%4]
+			h := b ^ c ^ d
+			a += h + X[x] + 0x6ed9eba1
+			a = a<<s | a>>(32-s)
+			a, b, c, d = d, a, b, c
+		}
+
+		a += aa
+		b += bb
+		c += cc
+		d += dd
+
+		p = p[_Chunk:]
+		n += _Chunk
+	}
+
+	dig.s[0] = a
+	dig.s[1] = b
+	dig.s[2] = c
+	dig.s[3] = d
+	return n
+}