53 lines
1.0 KiB
Go
53 lines
1.0 KiB
Go
// Copyright (C) 2019 Storj Labs, Inc.
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// See LICENSE for copying information.
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package psclient
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import (
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"crypto/hmac"
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"crypto/rand"
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"crypto/sha512"
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"github.com/mr-tron/base58/base58"
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)
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// PieceID is the unique identifier for pieces
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type PieceID string
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// NewPieceID creates a PieceID
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func NewPieceID() PieceID {
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b := make([]byte, 32)
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_, err := rand.Read(b)
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if err != nil {
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panic(err)
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}
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return PieceID(base58.Encode(b))
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}
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// String representation of the PieceID
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func (id PieceID) String() string {
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return string(id)
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}
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// IsValid checks if the current PieceID is valid
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func (id PieceID) IsValid() bool {
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return len(id) >= 20
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}
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// Derive a new PieceID from the current PieceID and the given secret
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func (id PieceID) Derive(secret []byte) (derived PieceID, err error) {
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mac := hmac.New(sha512.New, secret)
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_, err = mac.Write([]byte(id))
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if err != nil {
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return "", err
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}
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h := mac.Sum(nil)
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// Trim the hash if greater than 32 bytes
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if len(h) > 32 {
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h = h[:32]
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}
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return PieceID(base58.Encode(h)), nil
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}
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