Symmetric Key Algorithms
DES uses a 56-bit key and can be broken fairly easily. It is a block cipher—
it encrypts 64-bit blocks of data at a time.
3DES is also a block cipher, but it encrypts each block, decrypts it, and then
encrypts it again. A 56-bit key is used each time, thus equaling a key length
of 168 bits. It is more secure than DES but also requires more processing
power.
AES is a stronger block cipher encryption method than DES or 3DES. It
uses a 128-bit data block and a key length of 128, 192, or 256 bits. AES has
been approved for use with government classified data.