func randBytes(numBytes int) []byte {
	b := make([]byte, numBytes)
	_, err := crand.Read(b)
	if err != nil {
		PanicCrisis(err)
	}
	return b
}
This only uses the OS's randomness
package crypto
import (
	"crypto/aes"
	"crypto/cipher"
	crand "crypto/rand"
	"encoding/hex"
	"io"
	"sync"
	. "github.com/annchain/annchain/module/lib/go-common"
)
var gRandInfo *randInfo
func init() {
	gRandInfo = &randInfo{}
	gRandInfo.MixEntropy(randBytes(32))  
}
func MixEntropy(seedBytes []byte) {
	gRandInfo.MixEntropy(seedBytes)
}