Four modes in symmetric encryption and packet encryption (ECB, CBC, CFB, OFB)
a
. AES
Symmetric encryption
:
AES Encryption
Group
two
.
padding for grouped passwords
The padding e.g for a grouped password.:
Pkcs#5 Fill Mode
three
.
Stream Password
:
Four
.
four modes in block cipher encryption
:
3.1 ECB
Mode
Advantages:1. Simple; 2. facilitates parallel computing; 3. errors are not transmitted;
Disadvantages:1. Cannot hide the clear text mode; 2. Active attacks on plaintext may occur;
3.2 CBC
mode:
Advantages:1. Not easy to actively attack, security better than the ECB, suitable for transmitting long-length messages, is the standard of SSL, IPSec.
Disadvantages:1. Not conducive to parallel computing; 2. Error transfer; 3. Required Initialization Vector IV
3.3 CFB
mode:
Advantages:1. The plaintext mode is hidden, 2. The block cipher is converted to stream mode; 3. Can encrypt and transmit data less than packet in time;
Disadvantages:1. Not conducive to parallel computing; 2. Error transfer: A clear text unit damage affects multiple cells; 3. The only IV;
3.4 OFB
mode:
Advantages:1. The plaintext mode is hidden, 2. The block cipher is converted to stream mode; 3. Can encrypt and transmit data less than packet in time;
Disadvantages:1. Not conducive to parallel computing; 2. Active attacks on plaintext are possible; 3. Error transmission: A clear text unit damage affects multiple units;
Four modes of AES encryption
