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math/rand/v2: add ChaCha8.Read
Fixes #67059 Closes #67452 Closes #67498 Change-Id: I84eba2ed787a17e9d6aaad2a8a78596e3944909a Reviewed-on: https://go-review.googlesource.com/c/go/+/587280 Reviewed-by: Roland Shoemaker <roland@golang.org> Auto-Submit: Filippo Valsorda <filippo@golang.org> Reviewed-by: Carlos Amedee <carlos@golang.org> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
This commit is contained in:
Filippo Valsorda
Gopher Robot
parent
6dd79d02f8
commit
587c3847da
1
api/next/67059.txt
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1
api/next/67059.txt
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@ -0,0 +1 @@
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pkg math/rand/v2, method (*ChaCha8) Read([]uint8) (int, error) #67059
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1
doc/next/6-stdlib/99-minor/math/rand/v2/67059.md
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1
doc/next/6-stdlib/99-minor/math/rand/v2/67059.md
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@ -0,0 +1 @@
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The new [ChaCha8.Read] method implements the [io.Reader] interface.
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@ -474,6 +474,7 @@ func Shuffle(n int, swap func(i, j int)) { globalRand().Shuffle(n, swap) }
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// Read, unlike the [Rand.Read] method, is safe for concurrent use.
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//
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// Deprecated: For almost all use cases, [crypto/rand.Read] is more appropriate.
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// If a deterministic source is required, use [math/rand/v2.ChaCha8.Read].
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func Read(p []byte) (n int, err error) { return globalRand().Read(p) }
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// NormFloat64 returns a normally distributed float64 in the range
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@ -4,12 +4,20 @@
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package rand
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import "internal/chacha8rand"
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import (
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"errors"
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"internal/byteorder"
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"internal/chacha8rand"
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)
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// A ChaCha8 is a ChaCha8-based cryptographically strong
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// random number generator.
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type ChaCha8 struct {
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state chacha8rand.State
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// The last readLen bytes of readBuf are still to be consumed by Read.
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readBuf [8]byte
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readLen int // 0 <= readLen <= 8
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}
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// NewChaCha8 returns a new ChaCha8 seeded with the given seed.
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@ -22,6 +30,8 @@ func NewChaCha8(seed [32]byte) *ChaCha8 {
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// Seed resets the ChaCha8 to behave the same way as NewChaCha8(seed).
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func (c *ChaCha8) Seed(seed [32]byte) {
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c.state.Init(seed)
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c.readLen = 0
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c.readBuf = [8]byte{}
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}
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// Uint64 returns a uniformly distributed random uint64 value.
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@ -35,12 +45,66 @@ func (c *ChaCha8) Uint64() uint64 {
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}
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}
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// Read reads exactly len(p) bytes into p.
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// It always returns len(p) and a nil error.
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//
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// If calls to Read and Uint64 are interleaved, the order in which bits are
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// returned by the two is undefined, and Read may return bits generated before
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// the last call to Uint64.
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func (c *ChaCha8) Read(p []byte) (n int, err error) {
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if c.readLen > 0 {
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n = copy(p, c.readBuf[len(c.readBuf)-c.readLen:])
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c.readLen -= n
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p = p[n:]
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}
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for len(p) >= 8 {
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byteorder.LePutUint64(p, c.Uint64())
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p = p[8:]
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n += 8
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}
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if len(p) > 0 {
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byteorder.LePutUint64(c.readBuf[:], c.Uint64())
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n += copy(p, c.readBuf[:])
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c.readLen = 8 - len(p)
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}
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return
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}
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// UnmarshalBinary implements the encoding.BinaryUnmarshaler interface.
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func (c *ChaCha8) UnmarshalBinary(data []byte) error {
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data, ok := cutPrefix(data, []byte("readbuf:"))
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if ok {
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var buf []byte
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buf, data, ok = readUint8LengthPrefixed(data)
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if !ok {
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return errors.New("invalid ChaCha8 Read buffer encoding")
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}
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c.readLen = copy(c.readBuf[len(c.readBuf)-len(buf):], buf)
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}
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return chacha8rand.Unmarshal(&c.state, data)
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}
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func cutPrefix(s, prefix []byte) (after []byte, found bool) {
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if len(s) < len(prefix) || string(s[:len(prefix)]) != string(prefix) {
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return s, false
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}
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return s[len(prefix):], true
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}
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func readUint8LengthPrefixed(b []byte) (buf, rest []byte, ok bool) {
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if len(b) == 0 || len(b) < int(1+b[0]) {
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return nil, nil, false
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}
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return b[1 : 1+b[0]], b[1+b[0]:], true
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}
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// MarshalBinary implements the encoding.BinaryMarshaler interface.
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func (c *ChaCha8) MarshalBinary() ([]byte, error) {
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if c.readLen > 0 {
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out := []byte("readbuf:")
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out = append(out, uint8(c.readLen))
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out = append(out, c.readBuf[len(c.readBuf)-c.readLen:]...)
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return append(out, chacha8rand.Marshal(&c.state)...), nil
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}
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return chacha8rand.Marshal(&c.state), nil
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}
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@ -5,8 +5,13 @@
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package rand_test
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import (
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"bytes"
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"crypto/sha256"
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"encoding/hex"
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"io"
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. "math/rand/v2"
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"testing"
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"testing/iotest"
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)
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func TestChaCha8(t *testing.T) {
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@ -25,6 +30,74 @@ func TestChaCha8(t *testing.T) {
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}
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}
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func TestChaCha8Read(t *testing.T) {
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p := NewChaCha8(chacha8seed)
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h := sha256.New()
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buf := make([]byte, chacha8outlen)
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if nn, err := p.Read(buf); err != nil {
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t.Fatal(err)
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} else if nn != len(buf) {
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t.Errorf("Read short: got %d, expected %d", nn, len(buf))
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}
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h.Write(buf)
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if got := h.Sum(nil); !bytes.Equal(got, chacha8hash) {
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t.Errorf("transcript incorrect: got %x, want %x", got, chacha8hash)
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}
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p.Seed(chacha8seed)
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h.Reset()
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buf = make([]byte, chacha8outlen)
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if _, err := io.ReadFull(iotest.OneByteReader(p), buf); err != nil {
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t.Errorf("one byte reads: %v", err)
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}
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h.Write(buf)
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if got := h.Sum(nil); !bytes.Equal(got, chacha8hash) {
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t.Errorf("transcript incorrect (one byte reads): got %x, want %x", got, chacha8hash)
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}
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p.Seed(chacha8seed)
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h.Reset()
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if n, err := p.Read(make([]byte, 0)); err != nil {
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t.Errorf("zero length read: %v", err)
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} else if n != 0 {
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t.Errorf("Read zero length: got %d, expected %d", n, 0)
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}
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var n int
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for n < chacha8outlen {
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if IntN(2) == 0 {
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out, err := p.MarshalBinary()
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if err != nil {
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t.Fatal(err)
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}
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if IntN(2) == 0 {
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p = NewChaCha8([32]byte{})
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}
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if err := p.UnmarshalBinary(out); err != nil {
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t.Fatal(err)
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}
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}
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buf := make([]byte, IntN(100))
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if n+len(buf) > chacha8outlen {
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buf = buf[:chacha8outlen-n]
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}
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n += len(buf)
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t.Logf("reading %d bytes", len(buf))
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if nn, err := p.Read(buf); err != nil {
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t.Fatal(err)
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} else if nn != len(buf) {
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t.Errorf("Read short: got %d, expected %d", nn, len(buf))
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}
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h.Write(buf)
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}
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if got := h.Sum(nil); !bytes.Equal(got, chacha8hash) {
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t.Errorf("transcript incorrect: got %x, want %x", got, chacha8hash)
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}
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}
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func TestChaCha8Marshal(t *testing.T) {
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p := NewChaCha8(chacha8seed)
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for i, x := range chacha8output {
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@ -33,7 +106,7 @@ func TestChaCha8Marshal(t *testing.T) {
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t.Fatalf("#%d: MarshalBinary: %v", i, err)
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}
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if string(enc) != chacha8marshal[i] {
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t.Fatalf("#%d: MarshalBinary=%q, want %q", i, enc, chacha8marshal[i])
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t.Errorf("#%d: MarshalBinary=%q, want %q", i, enc, chacha8marshal[i])
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}
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*p = ChaCha8{}
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if err := p.UnmarshalBinary(enc); err != nil {
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@ -45,6 +118,24 @@ func TestChaCha8Marshal(t *testing.T) {
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}
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}
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func TestChaCha8MarshalRead(t *testing.T) {
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p := NewChaCha8(chacha8seed)
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for i := range 50 {
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enc, err := p.MarshalBinary()
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if err != nil {
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t.Fatalf("#%d: MarshalBinary: %v", i, err)
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}
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if string(enc) != chacha8marshalread[i] {
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t.Errorf("#%d: MarshalBinary=%q, want %q", i, enc, chacha8marshalread[i])
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}
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*p = ChaCha8{}
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if err := p.UnmarshalBinary(enc); err != nil {
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t.Fatalf("#%d: UnmarshalBinary: %v", i, err)
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}
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p.Read(make([]byte, 1))
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}
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}
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func BenchmarkChaCha8(b *testing.B) {
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p := NewChaCha8([32]byte{1, 2, 3, 4, 5})
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var t uint64
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@ -54,11 +145,26 @@ func BenchmarkChaCha8(b *testing.B) {
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Sink = t
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}
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func BenchmarkChaCha8Read(b *testing.B) {
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p := NewChaCha8([32]byte{1, 2, 3, 4, 5})
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buf := make([]byte, 32)
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b.SetBytes(32)
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var t uint8
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for n := b.N; n > 0; n-- {
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p.Read(buf)
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t += buf[0]
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}
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Sink = uint64(t)
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}
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// Golden output test to make sure algorithm never changes,
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// so that its use in math/rand/v2 stays stable.
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var chacha8seed = [32]byte([]byte("ABCDEFGHIJKLMNOPQRSTUVWXYZ123456"))
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var chacha8outlen = 2976
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var chacha8hash, _ = hex.DecodeString("bfec3d418b829afe5df2d8887d1508348409c293b73758d7efd841dd995fe021")
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var chacha8output = []uint64{
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0xb773b6063d4616a5, 0x1160af22a66abc3c, 0x8c2599d9418d287c, 0x7ee07e037edc5cd6,
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0xcfaa9ee02d1c16ad, 0x0e090eef8febea79, 0x3c82d271128b5b3e, 0x9c5addc11252a34f,
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@ -529,3 +635,56 @@ var chacha8marshal = []string{
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"chacha8:\x00\x00\x00\x00\x00\x00\x00zK3\x9bB!,\x94\x9d\x975\xce'O_t\xee|\xb21\x87\xbb\xbb\xfd)\x8f\xe52\x01\vP\fk",
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"chacha8:\x00\x00\x00\x00\x00\x00\x00{K3\x9bB!,\x94\x9d\x975\xce'O_t\xee|\xb21\x87\xbb\xbb\xfd)\x8f\xe52\x01\vP\fk",
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}
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var chacha8marshalread = []string{
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"chacha8:\x00\x00\x00\x00\x00\x00\x00\x00ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\a\x16F=\x06\xb6s\xb7chacha8:\x00\x00\x00\x00\x00\x00\x00\x01ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x06F=\x06\xb6s\xb7chacha8:\x00\x00\x00\x00\x00\x00\x00\x01ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x05=\x06\xb6s\xb7chacha8:\x00\x00\x00\x00\x00\x00\x00\x01ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x04\x06\xb6s\xb7chacha8:\x00\x00\x00\x00\x00\x00\x00\x01ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x03\xb6s\xb7chacha8:\x00\x00\x00\x00\x00\x00\x00\x01ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x02s\xb7chacha8:\x00\x00\x00\x00\x00\x00\x00\x01ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x01\xb7chacha8:\x00\x00\x00\x00\x00\x00\x00\x01ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"chacha8:\x00\x00\x00\x00\x00\x00\x00\x01ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\a\xbcj\xa6\"\xaf`\x11chacha8:\x00\x00\x00\x00\x00\x00\x00\x02ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x06j\xa6\"\xaf`\x11chacha8:\x00\x00\x00\x00\x00\x00\x00\x02ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x05\xa6\"\xaf`\x11chacha8:\x00\x00\x00\x00\x00\x00\x00\x02ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x04\"\xaf`\x11chacha8:\x00\x00\x00\x00\x00\x00\x00\x02ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x03\xaf`\x11chacha8:\x00\x00\x00\x00\x00\x00\x00\x02ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x02`\x11chacha8:\x00\x00\x00\x00\x00\x00\x00\x02ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x01\x11chacha8:\x00\x00\x00\x00\x00\x00\x00\x02ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"chacha8:\x00\x00\x00\x00\x00\x00\x00\x02ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\a(\x8dAٙ%\x8cchacha8:\x00\x00\x00\x00\x00\x00\x00\x03ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x06\x8dAٙ%\x8cchacha8:\x00\x00\x00\x00\x00\x00\x00\x03ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x05Aٙ%\x8cchacha8:\x00\x00\x00\x00\x00\x00\x00\x03ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x04ٙ%\x8cchacha8:\x00\x00\x00\x00\x00\x00\x00\x03ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x03\x99%\x8cchacha8:\x00\x00\x00\x00\x00\x00\x00\x03ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x02%\x8cchacha8:\x00\x00\x00\x00\x00\x00\x00\x03ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x01\x8cchacha8:\x00\x00\x00\x00\x00\x00\x00\x03ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"chacha8:\x00\x00\x00\x00\x00\x00\x00\x03ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\a\\\xdc~\x03~\xe0~chacha8:\x00\x00\x00\x00\x00\x00\x00\x04ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x06\xdc~\x03~\xe0~chacha8:\x00\x00\x00\x00\x00\x00\x00\x04ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x05~\x03~\xe0~chacha8:\x00\x00\x00\x00\x00\x00\x00\x04ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x04\x03~\xe0~chacha8:\x00\x00\x00\x00\x00\x00\x00\x04ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x03~\xe0~chacha8:\x00\x00\x00\x00\x00\x00\x00\x04ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x02\xe0~chacha8:\x00\x00\x00\x00\x00\x00\x00\x04ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x01~chacha8:\x00\x00\x00\x00\x00\x00\x00\x04ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"chacha8:\x00\x00\x00\x00\x00\x00\x00\x04ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\a\x16\x1c-\xe0\x9e\xaa\xcfchacha8:\x00\x00\x00\x00\x00\x00\x00\x05ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x06\x1c-\xe0\x9e\xaa\xcfchacha8:\x00\x00\x00\x00\x00\x00\x00\x05ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x05-\xe0\x9e\xaa\xcfchacha8:\x00\x00\x00\x00\x00\x00\x00\x05ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x04\xe0\x9e\xaa\xcfchacha8:\x00\x00\x00\x00\x00\x00\x00\x05ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x03\x9e\xaa\xcfchacha8:\x00\x00\x00\x00\x00\x00\x00\x05ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x02\xaa\xcfchacha8:\x00\x00\x00\x00\x00\x00\x00\x05ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\x01\xcfchacha8:\x00\x00\x00\x00\x00\x00\x00\x05ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"chacha8:\x00\x00\x00\x00\x00\x00\x00\x05ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
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"readbuf:\a\xea\xeb\x8f\xef\x0e\t\x0echacha8:\x00\x00\x00\x00\x00\x00\x00\x06ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
|
||||
"readbuf:\x06\xeb\x8f\xef\x0e\t\x0echacha8:\x00\x00\x00\x00\x00\x00\x00\x06ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
|
||||
"readbuf:\x05\x8f\xef\x0e\t\x0echacha8:\x00\x00\x00\x00\x00\x00\x00\x06ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
|
||||
"readbuf:\x04\xef\x0e\t\x0echacha8:\x00\x00\x00\x00\x00\x00\x00\x06ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
|
||||
"readbuf:\x03\x0e\t\x0echacha8:\x00\x00\x00\x00\x00\x00\x00\x06ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
|
||||
"readbuf:\x02\t\x0echacha8:\x00\x00\x00\x00\x00\x00\x00\x06ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
|
||||
"readbuf:\x01\x0echacha8:\x00\x00\x00\x00\x00\x00\x00\x06ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
|
||||
"chacha8:\x00\x00\x00\x00\x00\x00\x00\x06ABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
|
||||
"readbuf:\a[\x8b\x12q҂<chacha8:\x00\x00\x00\x00\x00\x00\x00\aABCDEFGHIJKLMNOPQRSTUVWXYZ123456",
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user