1 files changed, 109 insertions, 0 deletions
diff --git a/vendor/golang.org/x/crypto/tea/cipher.go b/vendor/golang.org/x/crypto/tea/cipher.go
new file mode 100644
index 0000000..9c13d12
--- /dev/null
+++ b/vendor/golang.org/x/crypto/tea/cipher.go
@@ -0,0 +1,109 @@
+// Copyright 2015 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 tea implements the TEA algorithm, as defined in Needham and
+// Wheeler's 1994 technical report, “TEA, a Tiny Encryption Algorithm”. See
+// http://www.cix.co.uk/~klockstone/tea.pdf for details.
+
+package tea
+
+import (
+	"crypto/cipher"
+	"encoding/binary"
+	"errors"
+)
+
+const (
+	// BlockSize is the size of a TEA block, in bytes.
+	BlockSize = 8
+
+	// KeySize is the size of a TEA key, in bytes.
+	KeySize = 16
+
+	// delta is the TEA key schedule constant.
+	delta = 0x9e3779b9
+
+	// numRounds is the standard number of rounds in TEA.
+	numRounds = 64
+)
+
+// tea is an instance of the TEA cipher with a particular key.
+type tea struct {
+	key    [16]byte
+	rounds int
+}
+
+// NewCipher returns an instance of the TEA cipher with the standard number of
+// rounds. The key argument must be 16 bytes long.
+func NewCipher(key []byte) (cipher.Block, error) {
+	return NewCipherWithRounds(key, numRounds)
+}
+
+// NewCipherWithRounds returns an instance of the TEA cipher with a given
+// number of rounds, which must be even. The key argument must be 16 bytes
+// long.
+func NewCipherWithRounds(key []byte, rounds int) (cipher.Block, error) {
+	if len(key) != 16 {
+		return nil, errors.New("tea: incorrect key size")
+	}
+
+	if rounds&1 != 0 {
+		return nil, errors.New("tea: odd number of rounds specified")
+	}
+
+	c := &tea{
+		rounds: rounds,
+	}
+	copy(c.key[:], key)
+
+	return c, nil
+}
+
+// BlockSize returns the TEA block size, which is eight bytes. It is necessary
+// to satisfy the Block interface in the package "crypto/cipher".
+func (*tea) BlockSize() int {
+	return BlockSize
+}
+
+// Encrypt encrypts the 8 byte buffer src using the key in t 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 (t *tea) Encrypt(dst, src []byte) {
+	e := binary.BigEndian
+	v0, v1 := e.Uint32(src), e.Uint32(src[4:])
+	k0, k1, k2, k3 := e.Uint32(t.key[0:]), e.Uint32(t.key[4:]), e.Uint32(t.key[8:]), e.Uint32(t.key[12:])
+
+	sum := uint32(0)
+	delta := uint32(delta)
+
+	for i := 0; i < t.rounds/2; i++ {
+		sum += delta
+		v0 += ((v1 << 4) + k0) ^ (v1 + sum) ^ ((v1 >> 5) + k1)
+		v1 += ((v0 << 4) + k2) ^ (v0 + sum) ^ ((v0 >> 5) + k3)
+	}
+
+	e.PutUint32(dst, v0)
+	e.PutUint32(dst[4:], v1)
+}
+
+// Decrypt decrypts the 8 byte buffer src using the key in t and stores the
+// result in dst.
+func (t *tea) Decrypt(dst, src []byte) {
+	e := binary.BigEndian
+	v0, v1 := e.Uint32(src), e.Uint32(src[4:])
+	k0, k1, k2, k3 := e.Uint32(t.key[0:]), e.Uint32(t.key[4:]), e.Uint32(t.key[8:]), e.Uint32(t.key[12:])
+
+	delta := uint32(delta)
+	sum := delta * uint32(t.rounds/2) // in general, sum = delta * n
+
+	for i := 0; i < t.rounds/2; i++ {
+		v1 -= ((v0 << 4) + k2) ^ (v0 + sum) ^ ((v0 >> 5) + k3)
+		v0 -= ((v1 << 4) + k0) ^ (v1 + sum) ^ ((v1 >> 5) + k1)
+		sum -= delta
+	}
+
+	e.PutUint32(dst, v0)
+	e.PutUint32(dst[4:], v1)
+}