| // 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) { |
| clear(buf) |
| 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 |
| } |
