package crypto

import 

// FillBytes is safe version of (*big.Int).FillBytes.
// Returns false if to length is not exact equal to big.Int's.
// Otherwise fills to using b and returns true.
func ( *big.Int,  []byte) bool {
	 := .BitLen()
	if (+7)/8 > len() {
		return false
	}
	.FillBytes()
	return true
}