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mirror of https://github.com/henrydcase/nobs.git synced 2024-11-25 08:31:21 +00:00
nobs/drbg/internal/aes/tools.go
Kris Kwiatkowski 08f7315b64 DRBG: Speed improvements
* CTR-DRBG doesn't call "NewCipher" for block encryption
* Changes API of CTR-DRBG, so that read operation implementes io.Reader

Benchmark results:
----------------------
benchmark           old ns/op     new ns/op     delta
BenchmarkInit-4     1118          3579          +220.13%
BenchmarkRead-4     5343          14589         +173.05%

benchmark           old allocs     new allocs     delta
BenchmarkInit-4     15             0              -100.00%
BenchmarkRead-4     67             0              -100.00%

benchmark           old bytes     new bytes     delta
BenchmarkInit-4     1824          0             -100.00%
BenchmarkRead-4     9488          0             -100.00%
2019-04-09 14:37:59 +01:00

35 lines
1.2 KiB
Go

// Copyright 2018 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.
// +build !appengine
// Package subtle implements functions that are often useful in cryptographic
// code but require careful thought to use correctly.
//
// This is a mirror of golang.org/x/crypto/internal/subtle.
package aes
import "unsafe"
// AnyOverlap reports whether x and y share memory at any (not necessarily
// corresponding) index. The memory beyond the slice length is ignored.
func AnyOverlap(x, y []byte) bool {
return len(x) > 0 && len(y) > 0 &&
uintptr(unsafe.Pointer(&x[0])) <= uintptr(unsafe.Pointer(&y[len(y)-1])) &&
uintptr(unsafe.Pointer(&y[0])) <= uintptr(unsafe.Pointer(&x[len(x)-1]))
}
// InexactOverlap reports whether x and y share memory at any non-corresponding
// index. The memory beyond the slice length is ignored. Note that x and y can
// have different lengths and still not have any inexact overlap.
//
// InexactOverlap can be used to implement the requirements of the crypto/cipher
// AEAD, Block, BlockMode and Stream interfaces.
func InexactOverlap(x, y []byte) bool {
if len(x) == 0 || len(y) == 0 || &x[0] == &y[0] {
return false
}
return AnyOverlap(x, y)
}