Gecko [ 167.86.127.34 ]

Name	Size	Permission
benchmark_test.go	3.46 KB	-rw-r--r--
cbc.go	4.42 KB	-rw-r--r--
cbc_aes_test.go	2.93 KB	-rw-r--r--
cfb.go	1.94 KB	-rw-r--r--
cfb_test.go	2.77 KB	-rw-r--r--
cipher.go	2.49 KB	-rw-r--r--
cipher_test.go	2.2 KB	-rw-r--r--
common_test.go	1.24 KB	-rw-r--r--
ctr.go	2.12 KB	-rw-r--r--
ctr_aes_test.go	2.98 KB	-rw-r--r--
ctr_test.go	1.13 KB	-rw-r--r--
example_test.go	11.78 KB	-rw-r--r--
export_test.go	242 B	-rw-r--r--
gcm.go	13.82 KB	-rw-r--r--
gcm_test.go	21.3 KB	-rw-r--r--
io.go	1.46 KB	-rw-r--r--
ofb.go	1.6 KB	-rw-r--r--
ofb_test.go	2.95 KB	-rw-r--r--
xor_amd64.go	642 B	-rw-r--r--
xor_amd64.s	1.31 KB	-rw-r--r--
xor_generic.go	2.33 KB	-rw-r--r--
xor_ppc64x.go	641 B	-rw-r--r--
xor_ppc64x.s	2.03 KB	-rw-r--r--
xor_test.go	1.6 KB	-rw-r--r--

Code Editor : cfb.go

// 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

import "crypto/internal/subtle"

type cfb struct {
	b       Block
	next    []byte
	out     []byte
	outUsed int

decrypt bool
}

func (x *cfb) XORKeyStream(dst, src []byte) {
	if len(dst) < len(src) {
		panic("crypto/cipher: output smaller than input")
	}
	if subtle.InexactOverlap(dst[:len(src)], src) {
		panic("crypto/cipher: invalid buffer overlap")
	}
	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
}

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Code Editor : cfb.go