Question

Explain the One-time Pad scheme. Also, explain its security and practicality. Refer to page 1 in “Principles of modern cryptography” under “Computer and Network Security Course” notes

In few sentences please.

Answer 1

One-Time pad scheme:

• Invented during 1882
• Known as Vernam-Cipher
• Used for encryption
• Private Key (only one key is used to encrypt and decrypt the message)
• Random generation (Characters and strings) of private key - used once
• Cannot break this type of keys easily
• Calculated by modulo with the options of 10, 26 and 2
• Two copies of the key (for sender and recipient)
• This is not similar to OTP (One time Password)

Security: More secured if

• It is used only once
• generated randomly
• Done manually

Practical implementation:

Combination of 0s and 1s

See the attachment.

The number of keys I have asked is 1

and the length is 48

I have given the key length as 8 so only 8 characters are generated

You can opt for the ky types as number, characters etc

Type the word for which you need to generate OTP in the user-defined text box.

You can also generate a random One time pad using https://www.fourmilab.ch/onetime/otpjs.html

Note: The notes which you have specified is not available on the internet. I think that is your private notes. You can refer that notes in the given content.