79 lines
2.3 KiB
Go
79 lines
2.3 KiB
Go
// Copyright 2016 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package api
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import (
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"encoding/binary"
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"errors"
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"github.com/ethereum/go-ethereum/swarm/storage/encryption"
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"golang.org/x/crypto/sha3"
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)
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type RefEncryption struct {
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refSize int
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span []byte
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}
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func NewRefEncryption(refSize int) *RefEncryption {
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span := make([]byte, 8)
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binary.LittleEndian.PutUint64(span, uint64(refSize))
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return &RefEncryption{
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refSize: refSize,
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span: span,
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}
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}
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func (re *RefEncryption) Encrypt(ref []byte, key []byte) ([]byte, error) {
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spanEncryption := encryption.New(key, 0, uint32(re.refSize/32), sha3.NewLegacyKeccak256)
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encryptedSpan, err := spanEncryption.Encrypt(re.span)
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if err != nil {
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return nil, err
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}
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dataEncryption := encryption.New(key, re.refSize, 0, sha3.NewLegacyKeccak256)
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encryptedData, err := dataEncryption.Encrypt(ref)
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if err != nil {
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return nil, err
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}
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encryptedRef := make([]byte, len(ref)+8)
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copy(encryptedRef[:8], encryptedSpan)
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copy(encryptedRef[8:], encryptedData)
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return encryptedRef, nil
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}
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func (re *RefEncryption) Decrypt(ref []byte, key []byte) ([]byte, error) {
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spanEncryption := encryption.New(key, 0, uint32(re.refSize/32), sha3.NewLegacyKeccak256)
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decryptedSpan, err := spanEncryption.Decrypt(ref[:8])
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if err != nil {
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return nil, err
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}
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size := binary.LittleEndian.Uint64(decryptedSpan)
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if size != uint64(len(ref)-8) {
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return nil, errors.New("invalid span in encrypted reference")
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}
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dataEncryption := encryption.New(key, re.refSize, 0, sha3.NewLegacyKeccak256)
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decryptedRef, err := dataEncryption.Decrypt(ref[8:])
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if err != nil {
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return nil, err
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}
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return decryptedRef, nil
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}
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