tracker/middleware/pkg/random/entropy.go
2017-06-19 09:45:26 +02:00

17 lines
585 B
Go

package random
import (
"encoding/binary"
"github.com/chihaya/chihaya/bittorrent"
)
// DeriveEntropyFromRequest generates 2*64 bits of pseudo random state from an
// AnnounceRequest.
//
// Calling DeriveEntropyFromRequest multiple times yields the same values.
func DeriveEntropyFromRequest(req *bittorrent.AnnounceRequest) (uint64, uint64) {
v0 := binary.BigEndian.Uint64([]byte(req.InfoHash[:8])) + binary.BigEndian.Uint64([]byte(req.InfoHash[8:16]))
v1 := binary.BigEndian.Uint64([]byte(req.Peer.ID[:8])) + binary.BigEndian.Uint64([]byte(req.Peer.ID[8:16]))
return v0, v1
}