Definition
An OTP is an encryption method that is impossible to decipher when employed correctly. It uses a random data string called the pad, which has the same length as the initial message.
The message is encrypted by integrating it with the pad using a modular addition or bitwise XOR techniques. Every separate character or bit of the plaintext is mixed with the corresponding character or bit from the pad.
History of the One-time Pad
- 1882: Frank Miller originally introduced the concept of one-time pad encryption. He defined the OTP idea as the encryption of plaintext using a key, which is a random suite of numbers. Every digit should be employed only once and then discarded.
- 1917: Gilbert Vernam, an AT&T engineer, designed and patented a cipher structure for telegraphy. The process involved merging the plaintext message with a cipher tape created by a teletypewriter. This is regarded as the official introduction of the OTP encryption technology.
- World War II and Cold War: OTPs were commonly used for confidential military and diplomatic communication. The pad, comprising of random keys, was printed on little pieces of flash paper to destroy the key after usage.
- 1949: Claude Shannon, dubbed ‘the father of modern cryptography’, proved that one-time pad encryption could not be decrypted. However, this could only be true if the key was completely random, the same length as the plaintext, never reused and kept secret.
