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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /libgo/go/crypto/cipher/cipher.go | |
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Diffstat (limited to 'libgo/go/crypto/cipher/cipher.go')
-rw-r--r-- | libgo/go/crypto/cipher/cipher.go | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/libgo/go/crypto/cipher/cipher.go b/libgo/go/crypto/cipher/cipher.go new file mode 100644 index 000000000..50516b23a --- /dev/null +++ b/libgo/go/crypto/cipher/cipher.go @@ -0,0 +1,63 @@ +// 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. + +// The cipher package implements standard block cipher modes +// that can be wrapped around low-level block cipher implementations. +// See http://csrc.nist.gov/groups/ST/toolkit/BCM/current_modes.html +// and NIST Special Publication 800-38A. +package cipher + +// A Block represents an implementation of block cipher +// using a given key. It provides the capability to encrypt +// or decrypt individual blocks. The mode implementations +// extend that capability to streams of blocks. +type Block interface { + // BlockSize returns the cipher's block size. + BlockSize() int + + // Encrypt encrypts the first block in src into dst. + // Dst and src may point at the same memory. + Encrypt(dst, src []byte) + + // Decrypt decrypts the first block in src into dst. + // Dst and src may point at the same memory. + Decrypt(dst, src []byte) +} + +// A Stream represents a stream cipher. +type Stream interface { + // XORKeyStream XORs each byte in the given slice with a byte from the + // cipher's key stream. Dst and src may point to the same memory. + XORKeyStream(dst, src []byte) +} + +// A BlockMode represents a block cipher running in a block-based mode (CBC, +// ECB etc). +type BlockMode interface { + // BlockSize returns the mode's block size. + BlockSize() int + + // CryptBlocks encrypts or decrypts a number of blocks. The length of + // src must be a multiple of the block size. Dst and src may point to + // the same memory. + CryptBlocks(dst, src []byte) +} + +// Utility routines + +func shift1(dst, src []byte) byte { + var b byte + for i := len(src) - 1; i >= 0; i-- { + bb := src[i] >> 7 + dst[i] = src[i]<<1 | b + b = bb + } + return b +} + +func dup(p []byte) []byte { + q := make([]byte, len(p)) + copy(q, p) + return q +} |