!
>#
>$
>-
>.
(dot)- Numbers
- Leading space (although the space doesn't appear after saving, the sort order is still updated)
- incorrect
_
(underscore)- Letters (case insensitive)
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
#include <stdio.h> | |
#include <stdlib.h> | |
#include <string.h> | |
int main(void) | |
{ | |
unsigned int a = 9; | |
unsigned int b = 9; | |
雙方使用的同一個金鑰,既可以加密又可以解密,這種加密方法稱為對稱加密,也稱為單金鑰加密。 在對稱加密演算法中常用的演算法有:DES、AES等。
- 優點:速度快,對稱性加密通常在訊息傳送方需要加密大量資料時使用,演算法公開、計算量小、加密速度快、加密效率高。
- 缺點:在資料傳送前,傳送方和接收方必須商定好祕鑰,然後 使雙方都能儲存好祕鑰。其次如果一方的祕鑰被洩露,那麼加密資訊也就不安全了。另外,每對使用者每次使用對稱加密演算法時,都需要使用其他人不知道的唯一祕鑰,這會使得收、發雙方所擁有的鑰匙數量巨大,金鑰管理成為雙方的負擔。
AES
進階加密標準(Advanced Encryption Standard),在密碼學中又稱Rijndael加密法,是美國聯邦政府採用的一種區塊加密標準。
The ARM processor has a simple privilege model. All modes are privileged apart from User mode.
Privilege is the ability to perform certain tasks that cannot be done from User mode.
For example, changing the operating mode is a privileged operation.
The processor modes are:
- Thread Mode