Symmetric Key Cryptography

Example № 2 of using XOR for symmetric encryption and decryption:

• The message "hi", in ASCII binary, is: 01101000 01101001. We create a random key of the same length:
  00111010 10110010, and encrypt:

  Data	0	1	1	0	1	0	0	0		0	1	1	0	1	0	0	1
  Key	0	0	1	1	1	0	1	0		1	0	1	1	0	0	1	0
  Ciphertext	0	1	0	1	0	0	1	0		1	1	0	1	1	0	1	1

  the ciphertext won't necessarily be English letters. In our case, the ciphertext is: R█ (R and 'full block'.)
• Again, we use the same key to decrypt the ciphertext back to the message "hi":

  Ciphertext	0	1	0	1	0	0	1	0		1	1	0	1	1	0	1	1
  Key	0	0	1	1	1	0	1	0		1	0	1	1	0	0	1	0
  Data	0	1	1	0	1	0	0	0		0	1	1	0	1	0	0	1