AIM:  Write a C/JAVA program to implement the Rijndael algorithm logic. HARDWARE AND SOFTWARE REQUIREMENT: 1. Intel based Desktop PC: - RAM of 512 MB 2. Notepad/Notepad ++ editor    and Command Prompt or 3. IntelliJ IDEA Community Edition THEORY: Ø    Rijndael is advanced version of AES(which is defined for fixed block size i.e.128 bit) which defined for variable length block sizes i.e.128,192 and 256 bits Ø    If a different block size between encryption and decryption is used, then it is not possible to recover the original plaintext. Ø    The Rijndael algorithm is a new generation symmetric encryption algorithm. Ø    It is  block cipher  algorithm data handling happened in 128-bits blocks,variable key length & variable round number. Ø    Encryption under Rijndael is achieved through a series of  matrix transformations  . Each transformation is known as a ...

HARDWARE AND SOFTWARE REQUIREMENT: 1. Intel based Desktop PC: - RAM of 512 MB 2. Notepad/Notepad ++ editor    and Command Prompt or 3. IntelliJ IDEA Community Edition THEORY: Ø    Blowfish is also an encryption technique which is replacement to DES algorithm and that is    very powerful ammunition against hackers and cyber-criminals. It is utilized in a wide array of products like in performance-constrained environments such as embedded systems, secure E-mail encryption tools, backup software, password management tools. Ø    It is a symmetric key encryption algorithm in which the same secret key is used for both encryption and decryption i.e. same secret key is used by sender and receiver and it is kept secret. Ø    It is block cipher algorithm i.e. The message is divided into fixed length blocks (64-bits) during encryption and decryption. The key size ranges from 32 to 448 bits(variable length key is...

Hill Cipher :     Ø    The Hill cipher is a poly-graphic substitution cipher (plaintext letters are substituted in larger groups, instead of substituting letters individually i.e. Works on multiple letters at same time). Ø    In this Hill cipher technique, the KEY and PLAINTEXT must be in the form of square matrix. Ø    The KEY must be chosen randomly according to PLAINTEXT. ENCRYPTION: Ø    To encrypt the message, we will use the formula  C=K.P mod  26  where C is Ciphertext, K is the Key, P is Plaintext. Ø    Each letter is represented by a number  modulo   26 . Often following simple scheme is used. A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Ø    By using above value table we have ...

Substitution Cipher HARDWARE AND SOFTWARE REQUIREMENT: 1. Intel based Desktop PC: - RAM of 512 MB 2. Notepad/Notepad ++ editor 3.Turbo C++ Ø    Substitution ciphers are probably the most common form of cipher. They work by replacing each letter of the plaintext (and sometimes punctuation marks and spaces) with another letter (or possibly even a random symbol). Ø    A  monoalphabetic substitution cipher , also known as a simple substitution cipher, relies on a fixed replacement structure. Ø    That is, the replacement(substitution) is fixed for each letter of the alphabet. Thus, if "b" is encrypted to "S", then every time whenever we encounter the letter "b" in the plaintext, we replace it with the letter "S" in the ciphertext. Ø    A simple example is which each letter is encrypted as the next letter in the alphabet:  "online smart trainer "  becomes "POMJOF TNBSU USBJOFS". Ø    In general, wh...