summaryrefslogtreecommitdiff
path: root/src/pkg/crypto/cipher/ctr.go
diff options
context:
space:
mode:
Diffstat (limited to 'src/pkg/crypto/cipher/ctr.go')
-rw-r--r--src/pkg/crypto/cipher/ctr.go55
1 files changed, 0 insertions, 55 deletions
diff --git a/src/pkg/crypto/cipher/ctr.go b/src/pkg/crypto/cipher/ctr.go
deleted file mode 100644
index 147b74fc2..000000000
--- a/src/pkg/crypto/cipher/ctr.go
+++ /dev/null
@@ -1,55 +0,0 @@
-// 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.
-
-// Counter (CTR) mode.
-
-// CTR converts a block cipher into a stream cipher by
-// repeatedly encrypting an incrementing counter and
-// xoring the resulting stream of data with the input.
-
-// See NIST SP 800-38A, pp 13-15
-
-package cipher
-
-type ctr struct {
- b Block
- ctr []byte
- out []byte
- outUsed int
-}
-
-// NewCTR returns a Stream which encrypts/decrypts using the given Block in
-// counter mode. The length of iv must be the same as the Block's block size.
-func NewCTR(block Block, iv []byte) Stream {
- if len(iv) != block.BlockSize() {
- panic("cipher.NewCTR: iv length must equal block size")
- }
-
- return &ctr{
- b: block,
- ctr: dup(iv),
- out: make([]byte, len(iv)),
- outUsed: len(iv),
- }
-}
-
-func (x *ctr) XORKeyStream(dst, src []byte) {
- for i := 0; i < len(src); i++ {
- if x.outUsed == len(x.ctr) {
- x.b.Encrypt(x.out, x.ctr)
- x.outUsed = 0
-
- // Increment counter
- for i := len(x.ctr) - 1; i >= 0; i-- {
- x.ctr[i]++
- if x.ctr[i] != 0 {
- break
- }
- }
- }
-
- dst[i] = src[i] ^ x.out[x.outUsed]
- x.outUsed++
- }
-}