// Reseed reseeds the generator with the given arbitrary input.
func (g *Generator) Reseed(s string) {
h := sha3.NewKeccak256()
h.Write(g.key[:])
h.Write([]byte(s))
key := h.Sum(nil)
copy(g.key[:], key)
zero(key)
h.Reset()
incCounter(g.ctr)
}
// Write performs the same operation as Reseed, but allows the
// generator to be used as an io.Writer.
func (g *Generator) Write(bs []byte) (int, error) {
h := sha3.NewKeccak256()
h.Write(g.key[:])
h.Write(bs)
key := h.Sum(nil)
copy(g.key[:], key)
zero(key)
h.Reset()
incCounter(g.ctr)
return len(bs), nil
}
// getHash calculates the hash of a file.
// It reads a file block by block, and updates a hashsum with each block.
// Reading by blocks consume very little memory, which is needed for large files.
// parameters:
// - fd is an open file descriptor that points to the file to inspect
// - hashType is an integer that define the type of hash
// return:
// - hexhash, the hex encoded hash of the file found at fp
func getHash(fd *os.File, hashType int) (hexhash string) {
if DEBUG {
fmt.Printf("getHash: computing hash for '%s'\n", fd.Name())
}
var h hash.Hash
switch hashType {
case CheckMD5:
h = md5.New()
case CheckSHA1:
h = sha1.New()
case CheckSHA256:
h = sha256.New()
case CheckSHA384:
h = sha512.New384()
case CheckSHA512:
h = sha512.New()
case CheckSHA3_224:
h = sha3.NewKeccak224()
case CheckSHA3_256:
h = sha3.NewKeccak256()
case CheckSHA3_384:
h = sha3.NewKeccak384()
case CheckSHA3_512:
h = sha3.NewKeccak512()
default:
err := fmt.Sprintf("getHash: Unkown hash type %d", hashType)
panic(err)
}
buf := make([]byte, 4096)
var offset int64 = 0
for {
block, err := fd.ReadAt(buf, offset)
if err != nil && err != io.EOF {
panic(err)
}
if block == 0 {
break
}
h.Write(buf[:block])
offset += int64(block)
}
hexhash = fmt.Sprintf("%x", h.Sum(nil))
return
}
func (rng *Tunafish) reseed() {
rng.counter++
s := []byte{}
for i := 0; i < len(rng.pools); i++ {
if ((1 << uint32(i)) | rng.counter) != 0 {
rng.pools[i].Lock()
h := sha3.NewKeccak256()
h.Write(rng.pools[i].hash)
s = append(s, h.Sum(nil)...)
rng.pools[i].hash = []byte{}
rng.pools[i].Unlock()
}
}
rng.g.Write(s)
rng.lastReseed.Lock()
rng.lastReseed.Time = time.Now()
rng.lastReseed.Unlock()
}
func Sha3Bin(data []byte) []byte {
d := sha3.NewKeccak256()
d.Write(data)
return d.Sum(nil)
}
func keccakMac(key, data []byte) []byte {
h := sha3.NewKeccak256()
h.Write(key)
h.Write(data)
return h.Sum(nil)
}