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481b5b230d
All validation has been moved to the API resources layer, i.e. the domain objects provide validation method, but the service itself assumes no corrupted values are passed to it. Signed-off-by: Dejan Mijic <dejan@mainflux.com>
84 lines
2.2 KiB
Go
84 lines
2.2 KiB
Go
// Copyright 2016 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 chacha20poly1305 implements the ChaCha20-Poly1305 AEAD as specified in RFC 7539.
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package chacha20poly1305
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import (
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"crypto/cipher"
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"errors"
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)
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const (
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// KeySize is the size of the key used by this AEAD, in bytes.
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KeySize = 32
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// NonceSize is the size of the nonce used with this AEAD, in bytes.
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NonceSize = 12
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)
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type chacha20poly1305 struct {
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key [32]byte
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}
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// New returns a ChaCha20-Poly1305 AEAD that uses the given, 256-bit key.
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func New(key []byte) (cipher.AEAD, error) {
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if len(key) != KeySize {
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return nil, errors.New("chacha20poly1305: bad key length")
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}
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ret := new(chacha20poly1305)
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copy(ret.key[:], key)
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return ret, nil
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}
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func (c *chacha20poly1305) NonceSize() int {
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return NonceSize
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}
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func (c *chacha20poly1305) Overhead() int {
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return 16
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}
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func (c *chacha20poly1305) Seal(dst, nonce, plaintext, additionalData []byte) []byte {
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if len(nonce) != NonceSize {
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panic("chacha20poly1305: bad nonce length passed to Seal")
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}
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if uint64(len(plaintext)) > (1<<38)-64 {
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panic("chacha20poly1305: plaintext too large")
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}
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return c.seal(dst, nonce, plaintext, additionalData)
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}
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var errOpen = errors.New("chacha20poly1305: message authentication failed")
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func (c *chacha20poly1305) Open(dst, nonce, ciphertext, additionalData []byte) ([]byte, error) {
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if len(nonce) != NonceSize {
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panic("chacha20poly1305: bad nonce length passed to Open")
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}
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if len(ciphertext) < 16 {
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return nil, errOpen
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}
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if uint64(len(ciphertext)) > (1<<38)-48 {
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panic("chacha20poly1305: ciphertext too large")
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}
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return c.open(dst, nonce, ciphertext, additionalData)
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}
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// sliceForAppend takes a slice and a requested number of bytes. It returns a
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// slice with the contents of the given slice followed by that many bytes and a
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// second slice that aliases into it and contains only the extra bytes. If the
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// original slice has sufficient capacity then no allocation is performed.
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func sliceForAppend(in []byte, n int) (head, tail []byte) {
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if total := len(in) + n; cap(in) >= total {
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head = in[:total]
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} else {
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head = make([]byte, total)
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copy(head, in)
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}
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tail = head[len(in):]
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return
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}
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