Nt1310 Unit 3 Assignment 1 Triple Data Encryption

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I Triple Data Encryption Standard (DES) is a modern variation DES where block cipher algorithms will applied three times to each data block. The algorithm uses a block of plaintext with 64 bits in length, and a 56 bit key. The actual key length equals that of the plaintext. However, the last bit on the right in each byte is a parity bit, and is disregarded as least significant, which is why 56 bits are the result. There were many concerns about the weakness of DES against brute force attacks due to the key length, so triple DES was developed in response to needing a stronger encryption method. Triple DES goes through three cycles during the encryption process by using three keys: encryption, decryption, and another encryption. It has a key …show more content…

To explain in further detail, assume that your key is A = B, B = C, and so on until you reach the end of the alphabet. (This is a sample key, but you can design it however you choose. However, nobody else but the intended recipients should have access to the key, as then it would be too easy to decrypt the message, defeating the purpose of encrypting it.) Your message in plaintext is “Don’t forget to drink your Ovaltine”. The key scrambles the plaintext, producing the ciphertext “Epou gpshu up esjol zpvs pwbmujof”. This process is known as the encryption function. The decryption function would take the ciphertext and key to produce the plaintext …show more content…

In this example, the innermost parentheses are first key and plaintext, which indicate the first key combined with the plaintext, and are encrypted. This produces the first ciphertext, which is in turn combined with the second key, and decrypted. The resulting ciphertext is combined with the third key, and encrypted one more time. The third ciphertext is the final result of this operation.

The following is the step for encrypt-decrypt-encrypt cycle (EDE):
1. Encrypt by using first key and plaintext in order to get the first ciphertext.
2. Decrypt by using first ciphertext and second key in order to get the second ciphertext.
3. Encrypt by using the second ciphertext and third key in order to get the third

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