ref: 4010db3078491baf3cb0d3d4e3a60c0cea114471
dir: /third_party/boringssl/src/ssl/test/runner/deterministic.go/
// Copyright (c) 2016, Google Inc.
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
package runner
import (
"encoding/binary"
"golang.org/x/crypto/chacha20"
)
// Use a different key from crypto/rand/deterministic.c.
var deterministicRandKey = []byte("runner deterministic key 0123456")
type deterministicRand struct {
numCalls uint64
}
func (d *deterministicRand) Read(buf []byte) (int, error) {
for i := range buf {
buf[i] = 0
}
var nonce [12]byte
binary.LittleEndian.PutUint64(nonce[:8], d.numCalls)
cipher, err := chacha20.NewUnauthenticatedCipher(deterministicRandKey, nonce[:])
if err != nil {
return 0, err
}
cipher.XORKeyStream(buf, buf)
d.numCalls++
return len(buf), nil
}