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// example1.go - a test program for the fortuna package
// Copyright (C) 2013 Jochen Voss <voss@seehuhn.de>
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
// +build ignore
package main
import (
"crypto/rand"
"fmt"
"io"
"log"
"net/http"
"strconv"
"time"
"github.com/seehuhn/fortuna"
)
const seedFileName = "seed.dat"
func main() {
rng, err := fortuna.NewRNG(seedFileName)
if err != nil {
panic("cannot initialise the RNG: " + err.Error())
}
defer rng.Close()
// entropy source 1: submit some randomness from crypto/rand once a minute
go func() {
sink1 := rng.NewEntropyDataSink()
for _ = range time.Tick(time.Minute) {
buffer := make([]byte, 4)
n, _ := rand.Read(buffer)
sink1 <- buffer[:n]
}
}()
// entropy source 2: submit time between requests
sink2 := rng.NewEntropyTimeStampSink()
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
sink2 <- time.Now()
sizeStr := r.URL.Query().Get("len")
size, _ := strconv.ParseInt(sizeStr, 0, 32)
if size <= 0 {
size = 16
}
w.Header().Set("Content-Length", fmt.Sprintf("%d", size))
io.CopyN(w, rng, size)
})
listenAddr := ":8080"
log.Printf("listening on http://localhost%s/", listenAddr)
err = http.ListenAndServe(listenAddr, nil)
if err != nil {
log.Fatal(err)
}
}