diff options
Diffstat (limited to 'vendor/golang.org/x/crypto/openpgp/packet/ocfb.go')
-rw-r--r-- | vendor/golang.org/x/crypto/openpgp/packet/ocfb.go | 143 |
1 files changed, 0 insertions, 143 deletions
diff --git a/vendor/golang.org/x/crypto/openpgp/packet/ocfb.go b/vendor/golang.org/x/crypto/openpgp/packet/ocfb.go deleted file mode 100644 index ce2a33a5..00000000 --- a/vendor/golang.org/x/crypto/openpgp/packet/ocfb.go +++ /dev/null @@ -1,143 +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. - -// OpenPGP CFB Mode. http://tools.ietf.org/html/rfc4880#section-13.9 - -package packet - -import ( - "crypto/cipher" -) - -type ocfbEncrypter struct { - b cipher.Block - fre []byte - outUsed int -} - -// An OCFBResyncOption determines if the "resynchronization step" of OCFB is -// performed. -type OCFBResyncOption bool - -const ( - OCFBResync OCFBResyncOption = true - OCFBNoResync OCFBResyncOption = false -) - -// NewOCFBEncrypter returns a cipher.Stream which encrypts data with OpenPGP's -// cipher feedback mode using the given cipher.Block, and an initial amount of -// ciphertext. randData must be random bytes and be the same length as the -// cipher.Block's block size. Resync determines if the "resynchronization step" -// from RFC 4880, 13.9 step 7 is performed. Different parts of OpenPGP vary on -// this point. -func NewOCFBEncrypter(block cipher.Block, randData []byte, resync OCFBResyncOption) (cipher.Stream, []byte) { - blockSize := block.BlockSize() - if len(randData) != blockSize { - return nil, nil - } - - x := &ocfbEncrypter{ - b: block, - fre: make([]byte, blockSize), - outUsed: 0, - } - prefix := make([]byte, blockSize+2) - - block.Encrypt(x.fre, x.fre) - for i := 0; i < blockSize; i++ { - prefix[i] = randData[i] ^ x.fre[i] - } - - block.Encrypt(x.fre, prefix[:blockSize]) - prefix[blockSize] = x.fre[0] ^ randData[blockSize-2] - prefix[blockSize+1] = x.fre[1] ^ randData[blockSize-1] - - if resync { - block.Encrypt(x.fre, prefix[2:]) - } else { - x.fre[0] = prefix[blockSize] - x.fre[1] = prefix[blockSize+1] - x.outUsed = 2 - } - return x, prefix -} - -func (x *ocfbEncrypter) XORKeyStream(dst, src []byte) { - for i := 0; i < len(src); i++ { - if x.outUsed == len(x.fre) { - x.b.Encrypt(x.fre, x.fre) - x.outUsed = 0 - } - - x.fre[x.outUsed] ^= src[i] - dst[i] = x.fre[x.outUsed] - x.outUsed++ - } -} - -type ocfbDecrypter struct { - b cipher.Block - fre []byte - outUsed int -} - -// NewOCFBDecrypter returns a cipher.Stream which decrypts data with OpenPGP's -// cipher feedback mode using the given cipher.Block. Prefix must be the first -// blockSize + 2 bytes of the ciphertext, where blockSize is the cipher.Block's -// block size. If an incorrect key is detected then nil is returned. On -// successful exit, blockSize+2 bytes of decrypted data are written into -// prefix. Resync determines if the "resynchronization step" from RFC 4880, -// 13.9 step 7 is performed. Different parts of OpenPGP vary on this point. -func NewOCFBDecrypter(block cipher.Block, prefix []byte, resync OCFBResyncOption) cipher.Stream { - blockSize := block.BlockSize() - if len(prefix) != blockSize+2 { - return nil - } - - x := &ocfbDecrypter{ - b: block, - fre: make([]byte, blockSize), - outUsed: 0, - } - prefixCopy := make([]byte, len(prefix)) - copy(prefixCopy, prefix) - - block.Encrypt(x.fre, x.fre) - for i := 0; i < blockSize; i++ { - prefixCopy[i] ^= x.fre[i] - } - - block.Encrypt(x.fre, prefix[:blockSize]) - prefixCopy[blockSize] ^= x.fre[0] - prefixCopy[blockSize+1] ^= x.fre[1] - - if prefixCopy[blockSize-2] != prefixCopy[blockSize] || - prefixCopy[blockSize-1] != prefixCopy[blockSize+1] { - return nil - } - - if resync { - block.Encrypt(x.fre, prefix[2:]) - } else { - x.fre[0] = prefix[blockSize] - x.fre[1] = prefix[blockSize+1] - x.outUsed = 2 - } - copy(prefix, prefixCopy) - return x -} - -func (x *ocfbDecrypter) XORKeyStream(dst, src []byte) { - for i := 0; i < len(src); i++ { - if x.outUsed == len(x.fre) { - x.b.Encrypt(x.fre, x.fre) - x.outUsed = 0 - } - - c := src[i] - dst[i] = x.fre[x.outUsed] ^ src[i] - x.fre[x.outUsed] = c - x.outUsed++ - } -} |