diff options
Diffstat (limited to 'src/pkg/crypto/cipher/cfb.go')
| -rw-r--r-- | src/pkg/crypto/cipher/cfb.go | 72 |
1 files changed, 0 insertions, 72 deletions
diff --git a/src/pkg/crypto/cipher/cfb.go b/src/pkg/crypto/cipher/cfb.go deleted file mode 100644 index 9b4eebf5b..000000000 --- a/src/pkg/crypto/cipher/cfb.go +++ /dev/null @@ -1,72 +0,0 @@ -// Copyright 2010 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. - -// CFB (Cipher Feedback) Mode. - -package cipher - -type cfb struct { - b Block - next []byte - out []byte - outUsed int - - decrypt bool -} - -func (x *cfb) XORKeyStream(dst, src []byte) { - for len(src) > 0 { - if x.outUsed == len(x.out) { - x.b.Encrypt(x.out, x.next) - x.outUsed = 0 - } - - if x.decrypt { - // We can precompute a larger segment of the - // keystream on decryption. This will allow - // larger batches for xor, and we should be - // able to match CTR/OFB performance. - copy(x.next[x.outUsed:], src) - } - n := xorBytes(dst, src, x.out[x.outUsed:]) - if !x.decrypt { - copy(x.next[x.outUsed:], dst) - } - dst = dst[n:] - src = src[n:] - x.outUsed += n - } -} - -// NewCFBEncrypter returns a Stream which encrypts with cipher feedback mode, -// using the given Block. The iv must be the same length as the Block's block -// size. -func NewCFBEncrypter(block Block, iv []byte) Stream { - return newCFB(block, iv, false) -} - -// NewCFBDecrypter returns a Stream which decrypts with cipher feedback mode, -// using the given Block. The iv must be the same length as the Block's block -// size. -func NewCFBDecrypter(block Block, iv []byte) Stream { - return newCFB(block, iv, true) -} - -func newCFB(block Block, iv []byte, decrypt bool) Stream { - blockSize := block.BlockSize() - if len(iv) != blockSize { - // stack trace will indicate whether it was de or encryption - panic("cipher.newCFB: IV length must equal block size") - } - x := &cfb{ - b: block, - out: make([]byte, blockSize), - next: make([]byte, blockSize), - outUsed: blockSize, - decrypt: decrypt, - } - copy(x.next, iv) - - return x -} |
