From 38ee83e45b4de7edf89bf9f0ef629eb4c6ad0fa8 Mon Sep 17 00:00:00 2001
From: Christopher Speller <crspeller@gmail.com>
Date: Thu, 12 May 2016 23:56:07 -0400
Subject: Moving to glide

---
 vendor/golang.org/x/crypto/xtea/block.go | 66 ++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 vendor/golang.org/x/crypto/xtea/block.go

(limited to 'vendor/golang.org/x/crypto/xtea/block.go')

diff --git a/vendor/golang.org/x/crypto/xtea/block.go b/vendor/golang.org/x/crypto/xtea/block.go
new file mode 100644
index 000000000..bf5d24599
--- /dev/null
+++ b/vendor/golang.org/x/crypto/xtea/block.go
@@ -0,0 +1,66 @@
+// 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.
+
+/*
+	Implementation adapted from Needham and Wheeler's paper:
+	http://www.cix.co.uk/~klockstone/xtea.pdf
+
+	A precalculated look up table is used during encryption/decryption for values that are based purely on the key.
+*/
+
+package xtea
+
+// XTEA is based on 64 rounds.
+const numRounds = 64
+
+// blockToUint32 reads an 8 byte slice into two uint32s.
+// The block is treated as big endian.
+func blockToUint32(src []byte) (uint32, uint32) {
+	r0 := uint32(src[0])<<24 | uint32(src[1])<<16 | uint32(src[2])<<8 | uint32(src[3])
+	r1 := uint32(src[4])<<24 | uint32(src[5])<<16 | uint32(src[6])<<8 | uint32(src[7])
+	return r0, r1
+}
+
+// uint32ToBlock writes two uint32s into an 8 byte data block.
+// Values are written as big endian.
+func uint32ToBlock(v0, v1 uint32, dst []byte) {
+	dst[0] = byte(v0 >> 24)
+	dst[1] = byte(v0 >> 16)
+	dst[2] = byte(v0 >> 8)
+	dst[3] = byte(v0)
+	dst[4] = byte(v1 >> 24)
+	dst[5] = byte(v1 >> 16)
+	dst[6] = byte(v1 >> 8)
+	dst[7] = byte(v1 >> 0)
+}
+
+// encryptBlock encrypts a single 8 byte block using XTEA.
+func encryptBlock(c *Cipher, dst, src []byte) {
+	v0, v1 := blockToUint32(src)
+
+	// Two rounds of XTEA applied per loop
+	for i := 0; i < numRounds; {
+		v0 += ((v1<<4 ^ v1>>5) + v1) ^ c.table[i]
+		i++
+		v1 += ((v0<<4 ^ v0>>5) + v0) ^ c.table[i]
+		i++
+	}
+
+	uint32ToBlock(v0, v1, dst)
+}
+
+// decryptBlock decrypt a single 8 byte block using XTEA.
+func decryptBlock(c *Cipher, dst, src []byte) {
+	v0, v1 := blockToUint32(src)
+
+	// Two rounds of XTEA applied per loop
+	for i := numRounds; i > 0; {
+		i--
+		v1 -= ((v0<<4 ^ v0>>5) + v0) ^ c.table[i]
+		i--
+		v0 -= ((v1<<4 ^ v1>>5) + v1) ^ c.table[i]
+	}
+
+	uint32ToBlock(v0, v1, dst)
+}
-- 
cgit v1.2.3-1-g7c22