// Copyright 2016 The go-ethereum Authors // This file is part of the go-ethereum library. // // The go-ethereum library is free software: you can redistribute it and/or modify // it under the terms of the GNU Lesser General Public License as published by // the Free Software Foundation, either version 3 of the License, or // (at your option) any later version. // // The go-ethereum library is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU Lesser General Public License for more details. // // You should have received a copy of the GNU Lesser General Public License // along with the go-ethereum library. If not, see . package api import ( "encoding/binary" "errors" "github.com/ethereum/go-ethereum/crypto/sha3" "github.com/ethereum/go-ethereum/swarm/storage/encryption" ) type RefEncryption struct { spanEncryption encryption.Encryption dataEncryption encryption.Encryption span []byte } func NewRefEncryption(refSize int) *RefEncryption { span := make([]byte, 8) binary.LittleEndian.PutUint64(span, uint64(refSize)) return &RefEncryption{ spanEncryption: encryption.New(0, uint32(refSize/32), sha3.NewKeccak256), dataEncryption: encryption.New(refSize, 0, sha3.NewKeccak256), span: span, } } func (re *RefEncryption) Encrypt(ref []byte, key []byte) ([]byte, error) { encryptedSpan, err := re.spanEncryption.Encrypt(re.span, key) if err != nil { return nil, err } encryptedData, err := re.dataEncryption.Encrypt(ref, key) if err != nil { return nil, err } encryptedRef := make([]byte, len(ref)+8) copy(encryptedRef[:8], encryptedSpan) copy(encryptedRef[8:], encryptedData) return encryptedRef, nil } func (re *RefEncryption) Decrypt(ref []byte, key []byte) ([]byte, error) { decryptedSpan, err := re.spanEncryption.Decrypt(ref[:8], key) if err != nil { return nil, err } size := binary.LittleEndian.Uint64(decryptedSpan) if size != uint64(len(ref)-8) { return nil, errors.New("invalid span in encrypted reference") } decryptedRef, err := re.dataEncryption.Decrypt(ref[8:], key) if err != nil { return nil, err } return decryptedRef, nil }