Create random.go

random.go

@@ -0,0 +1,83 @@
+package main
+/* copyright 2020 by moshix
+   crypto/rand number generator using /dev/random (depends on reliability of this Linux mechanism...
+   or connect to Java library for atmospheric noise random number generator as in second example
+*/
+
+import (
+	crand "crypto/rand"
+	rand "math/rand"
+
+	"encoding/binary"
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+)
+// check the numbers.log file with dieharder entropy checker with
+// dieharder -a -c ' ' -f numbers.log  where -c ' ' is the seperator between numbers
+func main() {
+    // check if numbers.log file is > 1MB delete it
+    var numsize int64
+    fileStat, err := os.Stat("numbers.log")
+    if err != nil {
+        log.Fatal(err)
+    }
+    numsize = fileStat.Size()
+    if numsize > 1000000 {
+       e := os.Remove("numbers.log") 
+    if e != nil { 
+        log.Fatal(e) 
+    } 
+    }
+
+	f, err := os.OpenFile("numbers.log",
+		os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0666)
+	if err != nil {
+		log.Println(err)
+	}
+	defer f.Close()
+	var number int
+	for i := 1; i < 14; i++ {
+		var src cryptoSource
+		rnd := rand.New(src)
+		number = rnd.Intn(899) + 100
+		s := strconv.Itoa(number)
+		fmt.Print(number)
+		fmt.Print(" ")
+		if _, err := f.WriteString(s + " "); err != nil {
+			log.Println(err)
+		}
+	}
+
+	fmt.Print(" ..... ") // seperator for block on web page
+      
+	for i := 1; i < 14; i++ {
+		var src cryptoSource
+		rnd := rand.New(src)
+		number = rnd.Intn(899) + 100
+		s := strconv.Itoa(number)
+		fmt.Print(number)
+		fmt.Print(" ")
+		if _, err := f.WriteString(s + " "); err != nil {
+			log.Println(err)
+		}
+	}
+
+}
+
+type cryptoSource struct{}
+
+func (s cryptoSource) Seed(seed int64) {}
+
+func (s cryptoSource) Int63() int64 {
+	return int64(s.Uint64() & ^uint64(1<<63))
+}
+
+func (s cryptoSource) Uint64() (v uint64) {
+	err := binary.Read(crand.Reader, binary.BigEndian, &v)
+	if err != nil {
+		log.Fatal(err)
+	}
+	return v
+}