protected int[] generate_num_k(String plain,int primer)
	{
		//special case: plain.length<primer.length
		int[] result=new int[plain.length()];
		String p_s=Integer.toString(primer);
		char[] p_array=p_s.toCharArray();
		int array_len=p_array.length;
	//	assert(p_array.length==5);
		int init=plain.length()<5?plain.length():5;
		for(int i=0;i<init;i++)
		{
			result[i]=p_array[i]-'0';
		}
		for(int i=array_len;i<result.length;i++)
		{
			int first=i-array_len;
			int second=i-array_len+1;
			int add_result=result[first]+result[second];
			add_result=add_result>=10?add_result-10:add_result;
			result[i]=add_result;
		}
		return result;
	}