(date + sha224) byte array

date_sha224.go

package main

// http://play.golang.org/p/F3XbXbmAgr
import (
	"fmt"
	"encoding/binary"
	"crypto/sha256"
	"io"
	"time"
)

func GetByteId() []byte {
	h := sha256.New224()
	io.WriteString(h, "foobar")
	return h.Sum(nil)
}

func main() {
	// 32 = 4 + 28 = (date) + (sha224)
	u := [32]byte{}

	// time by int32
	t := time.Now()
	n := t.Day() + int(t.Month()) * 32 + t.Year() * 32 * 16

	// sha224
	b := GetByteId()

	// write time as uint32
	// the first entry should be 0
	binary.BigEndian.PutUint32(u[0:], uint32(n))
	copy(u[4:], b)
	fmt.Println(u)
	fmt.Println(b)
}