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https://github.com/superseriousbusiness/gotosocial.git
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98eef328ea
Bumps [golang.org/x/net](https://github.com/golang/net) from 0.30.0 to 0.31.0. - [Commits](https://github.com/golang/net/compare/v0.30.0...v0.31.0) --- updated-dependencies: - dependency-name: golang.org/x/net dependency-type: direct:production update-type: version-update:semver-minor ... Signed-off-by: dependabot[bot] <support@github.com> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
194 lines
5.9 KiB
Go
194 lines
5.9 KiB
Go
// Copyright 2014 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package sha3
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// This file defines the ShakeHash interface, and provides
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// functions for creating SHAKE and cSHAKE instances, as well as utility
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// functions for hashing bytes to arbitrary-length output.
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//
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//
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// SHAKE implementation is based on FIPS PUB 202 [1]
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// cSHAKE implementations is based on NIST SP 800-185 [2]
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//
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// [1] https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.202.pdf
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// [2] https://doi.org/10.6028/NIST.SP.800-185
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import (
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"bytes"
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"encoding/binary"
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"errors"
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"hash"
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"io"
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"math/bits"
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)
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// ShakeHash defines the interface to hash functions that support
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// arbitrary-length output. When used as a plain [hash.Hash], it
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// produces minimum-length outputs that provide full-strength generic
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// security.
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type ShakeHash interface {
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hash.Hash
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// Read reads more output from the hash; reading affects the hash's
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// state. (ShakeHash.Read is thus very different from Hash.Sum)
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// It never returns an error, but subsequent calls to Write or Sum
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// will panic.
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io.Reader
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// Clone returns a copy of the ShakeHash in its current state.
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Clone() ShakeHash
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}
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// cSHAKE specific context
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type cshakeState struct {
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*state // SHA-3 state context and Read/Write operations
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// initBlock is the cSHAKE specific initialization set of bytes. It is initialized
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// by newCShake function and stores concatenation of N followed by S, encoded
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// by the method specified in 3.3 of [1].
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// It is stored here in order for Reset() to be able to put context into
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// initial state.
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initBlock []byte
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}
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func bytepad(data []byte, rate int) []byte {
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out := make([]byte, 0, 9+len(data)+rate-1)
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out = append(out, leftEncode(uint64(rate))...)
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out = append(out, data...)
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if padlen := rate - len(out)%rate; padlen < rate {
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out = append(out, make([]byte, padlen)...)
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}
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return out
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}
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func leftEncode(x uint64) []byte {
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// Let n be the smallest positive integer for which 2^(8n) > x.
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n := (bits.Len64(x) + 7) / 8
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if n == 0 {
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n = 1
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}
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// Return n || x with n as a byte and x an n bytes in big-endian order.
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b := make([]byte, 9)
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binary.BigEndian.PutUint64(b[1:], x)
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b = b[9-n-1:]
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b[0] = byte(n)
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return b
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}
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func newCShake(N, S []byte, rate, outputLen int, dsbyte byte) ShakeHash {
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c := cshakeState{state: &state{rate: rate, outputLen: outputLen, dsbyte: dsbyte}}
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c.initBlock = make([]byte, 0, 9+len(N)+9+len(S)) // leftEncode returns max 9 bytes
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c.initBlock = append(c.initBlock, leftEncode(uint64(len(N))*8)...)
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c.initBlock = append(c.initBlock, N...)
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c.initBlock = append(c.initBlock, leftEncode(uint64(len(S))*8)...)
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c.initBlock = append(c.initBlock, S...)
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c.Write(bytepad(c.initBlock, c.rate))
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return &c
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}
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// Reset resets the hash to initial state.
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func (c *cshakeState) Reset() {
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c.state.Reset()
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c.Write(bytepad(c.initBlock, c.rate))
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}
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// Clone returns copy of a cSHAKE context within its current state.
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func (c *cshakeState) Clone() ShakeHash {
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b := make([]byte, len(c.initBlock))
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copy(b, c.initBlock)
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return &cshakeState{state: c.clone(), initBlock: b}
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}
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// Clone returns copy of SHAKE context within its current state.
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func (c *state) Clone() ShakeHash {
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return c.clone()
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}
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func (c *cshakeState) MarshalBinary() ([]byte, error) {
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return c.AppendBinary(make([]byte, 0, marshaledSize+len(c.initBlock)))
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}
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func (c *cshakeState) AppendBinary(b []byte) ([]byte, error) {
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b, err := c.state.AppendBinary(b)
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if err != nil {
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return nil, err
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}
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b = append(b, c.initBlock...)
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return b, nil
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}
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func (c *cshakeState) UnmarshalBinary(b []byte) error {
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if len(b) <= marshaledSize {
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return errors.New("sha3: invalid hash state")
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}
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if err := c.state.UnmarshalBinary(b[:marshaledSize]); err != nil {
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return err
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}
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c.initBlock = bytes.Clone(b[marshaledSize:])
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return nil
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}
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// NewShake128 creates a new SHAKE128 variable-output-length ShakeHash.
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// Its generic security strength is 128 bits against all attacks if at
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// least 32 bytes of its output are used.
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func NewShake128() ShakeHash {
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return newShake128()
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}
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// NewShake256 creates a new SHAKE256 variable-output-length ShakeHash.
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// Its generic security strength is 256 bits against all attacks if
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// at least 64 bytes of its output are used.
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func NewShake256() ShakeHash {
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return newShake256()
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}
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func newShake128Generic() *state {
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return &state{rate: rateK256, outputLen: 32, dsbyte: dsbyteShake}
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}
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func newShake256Generic() *state {
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return &state{rate: rateK512, outputLen: 64, dsbyte: dsbyteShake}
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}
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// NewCShake128 creates a new instance of cSHAKE128 variable-output-length ShakeHash,
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// a customizable variant of SHAKE128.
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// N is used to define functions based on cSHAKE, it can be empty when plain cSHAKE is
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// desired. S is a customization byte string used for domain separation - two cSHAKE
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// computations on same input with different S yield unrelated outputs.
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// When N and S are both empty, this is equivalent to NewShake128.
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func NewCShake128(N, S []byte) ShakeHash {
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if len(N) == 0 && len(S) == 0 {
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return NewShake128()
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}
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return newCShake(N, S, rateK256, 32, dsbyteCShake)
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}
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// NewCShake256 creates a new instance of cSHAKE256 variable-output-length ShakeHash,
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// a customizable variant of SHAKE256.
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// N is used to define functions based on cSHAKE, it can be empty when plain cSHAKE is
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// desired. S is a customization byte string used for domain separation - two cSHAKE
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// computations on same input with different S yield unrelated outputs.
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// When N and S are both empty, this is equivalent to NewShake256.
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func NewCShake256(N, S []byte) ShakeHash {
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if len(N) == 0 && len(S) == 0 {
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return NewShake256()
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}
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return newCShake(N, S, rateK512, 64, dsbyteCShake)
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}
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// ShakeSum128 writes an arbitrary-length digest of data into hash.
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func ShakeSum128(hash, data []byte) {
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h := NewShake128()
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h.Write(data)
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h.Read(hash)
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}
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// ShakeSum256 writes an arbitrary-length digest of data into hash.
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func ShakeSum256(hash, data []byte) {
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h := NewShake256()
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h.Write(data)
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h.Read(hash)
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}
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