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crazy-max_diun/vendor/golang.org/x/crypto/sha3/sha3.go
dependabot[bot] 263c4afffd
chore(deps): bump golang.org/x/crypto from 0.21.0 to 0.31.0
Bumps [golang.org/x/crypto](https://github.com/golang/crypto) from 0.21.0 to 0.31.0.
- [Commits](https://github.com/golang/crypto/compare/v0.21.0...v0.31.0)

---
updated-dependencies:
- dependency-name: golang.org/x/crypto
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>
2024-12-15 11:13:51 +00:00

245 lines
6.5 KiB
Go

// Copyright 2014 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.
package sha3
import (
"crypto/subtle"
"encoding/binary"
"errors"
"unsafe"
"golang.org/x/sys/cpu"
)
// spongeDirection indicates the direction bytes are flowing through the sponge.
type spongeDirection int
const (
// spongeAbsorbing indicates that the sponge is absorbing input.
spongeAbsorbing spongeDirection = iota
// spongeSqueezing indicates that the sponge is being squeezed.
spongeSqueezing
)
type state struct {
a [1600 / 8]byte // main state of the hash
// a[n:rate] is the buffer. If absorbing, it's the remaining space to XOR
// into before running the permutation. If squeezing, it's the remaining
// output to produce before running the permutation.
n, rate int
// dsbyte contains the "domain separation" bits and the first bit of
// the padding. Sections 6.1 and 6.2 of [1] separate the outputs of the
// SHA-3 and SHAKE functions by appending bitstrings to the message.
// Using a little-endian bit-ordering convention, these are "01" for SHA-3
// and "1111" for SHAKE, or 00000010b and 00001111b, respectively. Then the
// padding rule from section 5.1 is applied to pad the message to a multiple
// of the rate, which involves adding a "1" bit, zero or more "0" bits, and
// a final "1" bit. We merge the first "1" bit from the padding into dsbyte,
// giving 00000110b (0x06) and 00011111b (0x1f).
// [1] http://csrc.nist.gov/publications/drafts/fips-202/fips_202_draft.pdf
// "Draft FIPS 202: SHA-3 Standard: Permutation-Based Hash and
// Extendable-Output Functions (May 2014)"
dsbyte byte
outputLen int // the default output size in bytes
state spongeDirection // whether the sponge is absorbing or squeezing
}
// BlockSize returns the rate of sponge underlying this hash function.
func (d *state) BlockSize() int { return d.rate }
// Size returns the output size of the hash function in bytes.
func (d *state) Size() int { return d.outputLen }
// Reset clears the internal state by zeroing the sponge state and
// the buffer indexes, and setting Sponge.state to absorbing.
func (d *state) Reset() {
// Zero the permutation's state.
for i := range d.a {
d.a[i] = 0
}
d.state = spongeAbsorbing
d.n = 0
}
func (d *state) clone() *state {
ret := *d
return &ret
}
// permute applies the KeccakF-1600 permutation.
func (d *state) permute() {
var a *[25]uint64
if cpu.IsBigEndian {
a = new([25]uint64)
for i := range a {
a[i] = binary.LittleEndian.Uint64(d.a[i*8:])
}
} else {
a = (*[25]uint64)(unsafe.Pointer(&d.a))
}
keccakF1600(a)
d.n = 0
if cpu.IsBigEndian {
for i := range a {
binary.LittleEndian.PutUint64(d.a[i*8:], a[i])
}
}
}
// pads appends the domain separation bits in dsbyte, applies
// the multi-bitrate 10..1 padding rule, and permutes the state.
func (d *state) padAndPermute() {
// Pad with this instance's domain-separator bits. We know that there's
// at least one byte of space in the sponge because, if it were full,
// permute would have been called to empty it. dsbyte also contains the
// first one bit for the padding. See the comment in the state struct.
d.a[d.n] ^= d.dsbyte
// This adds the final one bit for the padding. Because of the way that
// bits are numbered from the LSB upwards, the final bit is the MSB of
// the last byte.
d.a[d.rate-1] ^= 0x80
// Apply the permutation
d.permute()
d.state = spongeSqueezing
}
// Write absorbs more data into the hash's state. It panics if any
// output has already been read.
func (d *state) Write(p []byte) (n int, err error) {
if d.state != spongeAbsorbing {
panic("sha3: Write after Read")
}
n = len(p)
for len(p) > 0 {
x := subtle.XORBytes(d.a[d.n:d.rate], d.a[d.n:d.rate], p)
d.n += x
p = p[x:]
// If the sponge is full, apply the permutation.
if d.n == d.rate {
d.permute()
}
}
return
}
// Read squeezes an arbitrary number of bytes from the sponge.
func (d *state) Read(out []byte) (n int, err error) {
// If we're still absorbing, pad and apply the permutation.
if d.state == spongeAbsorbing {
d.padAndPermute()
}
n = len(out)
// Now, do the squeezing.
for len(out) > 0 {
// Apply the permutation if we've squeezed the sponge dry.
if d.n == d.rate {
d.permute()
}
x := copy(out, d.a[d.n:d.rate])
d.n += x
out = out[x:]
}
return
}
// Sum applies padding to the hash state and then squeezes out the desired
// number of output bytes. It panics if any output has already been read.
func (d *state) Sum(in []byte) []byte {
if d.state != spongeAbsorbing {
panic("sha3: Sum after Read")
}
// Make a copy of the original hash so that caller can keep writing
// and summing.
dup := d.clone()
hash := make([]byte, dup.outputLen, 64) // explicit cap to allow stack allocation
dup.Read(hash)
return append(in, hash...)
}
const (
magicSHA3 = "sha\x08"
magicShake = "sha\x09"
magicCShake = "sha\x0a"
magicKeccak = "sha\x0b"
// magic || rate || main state || n || sponge direction
marshaledSize = len(magicSHA3) + 1 + 200 + 1 + 1
)
func (d *state) MarshalBinary() ([]byte, error) {
return d.AppendBinary(make([]byte, 0, marshaledSize))
}
func (d *state) AppendBinary(b []byte) ([]byte, error) {
switch d.dsbyte {
case dsbyteSHA3:
b = append(b, magicSHA3...)
case dsbyteShake:
b = append(b, magicShake...)
case dsbyteCShake:
b = append(b, magicCShake...)
case dsbyteKeccak:
b = append(b, magicKeccak...)
default:
panic("unknown dsbyte")
}
// rate is at most 168, and n is at most rate.
b = append(b, byte(d.rate))
b = append(b, d.a[:]...)
b = append(b, byte(d.n), byte(d.state))
return b, nil
}
func (d *state) UnmarshalBinary(b []byte) error {
if len(b) != marshaledSize {
return errors.New("sha3: invalid hash state")
}
magic := string(b[:len(magicSHA3)])
b = b[len(magicSHA3):]
switch {
case magic == magicSHA3 && d.dsbyte == dsbyteSHA3:
case magic == magicShake && d.dsbyte == dsbyteShake:
case magic == magicCShake && d.dsbyte == dsbyteCShake:
case magic == magicKeccak && d.dsbyte == dsbyteKeccak:
default:
return errors.New("sha3: invalid hash state identifier")
}
rate := int(b[0])
b = b[1:]
if rate != d.rate {
return errors.New("sha3: invalid hash state function")
}
copy(d.a[:], b)
b = b[len(d.a):]
n, state := int(b[0]), spongeDirection(b[1])
if n > d.rate {
return errors.New("sha3: invalid hash state")
}
d.n = n
if state != spongeAbsorbing && state != spongeSqueezing {
return errors.New("sha3: invalid hash state")
}
d.state = state
return nil
}