Upgrading dependencies to include logrus.

vendor/golang.org/x/crypto/xtea/cipher.go

@@ -0,0 +1,82 @@
+// 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.
+
+// Package xtea implements XTEA encryption, as defined in Needham and Wheeler's
+// 1997 technical report, "Tea extensions."
+package xtea // import "golang.org/x/crypto/xtea"
+
+// For details, see http://www.cix.co.uk/~klockstone/xtea.pdf
+
+import "strconv"
+
+// The XTEA block size in bytes.
+const BlockSize = 8
+
+// A Cipher is an instance of an XTEA cipher using a particular key.
+type Cipher struct {
+	// table contains a series of precalculated values that are used each round.
+	table [64]uint32
+}
+
+type KeySizeError int
+
+func (k KeySizeError) Error() string {
+	return "crypto/xtea: invalid key size " + strconv.Itoa(int(k))
+}
+
+// NewCipher creates and returns a new Cipher.
+// The key argument should be the XTEA key.
+// XTEA only supports 128 bit (16 byte) keys.
+func NewCipher(key []byte) (*Cipher, error) {
+	k := len(key)
+	switch k {
+	default:
+		return nil, KeySizeError(k)
+	case 16:
+		break
+	}
+
+	c := new(Cipher)
+	initCipher(c, key)
+
+	return c, nil
+}
+
+// BlockSize returns the XTEA block size, 8 bytes.
+// It is necessary to satisfy the Block interface in the
+// package "crypto/cipher".
+func (c *Cipher) BlockSize() int { return BlockSize }
+
+// Encrypt encrypts the 8 byte buffer src using the key and stores the result in dst.
+// Note that for amounts of data larger than a block,
+// it is not safe to just call Encrypt on successive blocks;
+// instead, use an encryption mode like CBC (see crypto/cipher/cbc.go).
+func (c *Cipher) Encrypt(dst, src []byte) { encryptBlock(c, dst, src) }
+
+// Decrypt decrypts the 8 byte buffer src using the key and stores the result in dst.
+func (c *Cipher) Decrypt(dst, src []byte) { decryptBlock(c, dst, src) }
+
+// initCipher initializes the cipher context by creating a look up table
+// of precalculated values that are based on the key.
+func initCipher(c *Cipher, key []byte) {
+	// Load the key into four uint32s
+	var k [4]uint32
+	for i := 0; i < len(k); i++ {
+		j := i << 2 // Multiply by 4
+		k[i] = uint32(key[j+0])<<24 | uint32(key[j+1])<<16 | uint32(key[j+2])<<8 | uint32(key[j+3])
+	}
+
+	// Precalculate the table
+	const delta = 0x9E3779B9
+	var sum uint32
+
+	// Two rounds of XTEA applied per loop
+	for i := 0; i < numRounds; {
+		c.table[i] = sum + k[sum&3]
+		i++
+		sum += delta
+		c.table[i] = sum + k[(sum>>11)&3]
+		i++
+	}
+}