对称/分组密码一般分为流加密(如OFB、CFB等)和块加密(如ECB、CBC等)。对于流加密，需要将分组密码转化为流模式工作。对于块加密(或称分组加密)，如果要加密超过块大小的数据，就需要涉及填充和链加密模式，文中提到的ECB和CBC等就是指链加密模式。 本文将要介绍了AES对称加密/分组加密/流密码及其ECB、CBC、CFB、OFB和CTR五种对称加密模式。,Symmetric/block ciphers are generally divided into stream encryption

Wireless Sensor Networks (WSN) are becoming popular day by day, however one of the main issue in WSN is its limited resources. We have to look to the resources to create Message Authentication Code (MAC) keeping in mind the feasibility of techn