The abstract focuses on the five models of symmetric key algorithm. The cryptography is encapsulating the data with a security key for both encrypting and decrypting. First the plain text is converted in to cipher text by a key and it is send to the receiver side after that the receiver decrypts by the key which was sent by the sender.

Five Models:

#### Ø Data Encryption Standard (DES)

**Advanced Encryption Standard (AES)****International Data Encryption Algorithm (IDEA***)***Blow Fish****CAST**

#### Data Encryption Standard (DES):

DES is also called as digital standard encryption system. DES encrypts or Decrypts the data using 56-bit key. The 64-bit text is taken as input and 64-bit cipher text is produced as output. The algorithm uses both substations and permutations. The strengths of DES are

- Triple DES
- DESX

**Advanced Encryption Standard (AES):**

For the government application purpose the AES encryption standard system was invented. AES uses an SKC scheme called Rijndael. The key lengths are 128, 192, 256 bit encryptions.. The AES algorithm of 128-bit was approved by the NIST in 2001.

**International Data Encryption Algorithm (IDEA***)**:*

IDEA is an method of encryption algorithm. It is a 64-bit block cipher text. It uses 128-bit key. The key length is very difficult to break the code. It is resistant to linear and differential analysis.

**Blow Fish:**

Blowfish is a algorithm Which has high encryption standards? It over the weak points in the encrypting algorithms. Blowfish has block of 64-bit and a variable key length from between 32 to 4480 bits. It is considered to faster than DES.

#### CAST:

CAST full form is Carlisle Adams and Stafford Tavares. It uses 64-bit cipher encryption.CAST-128 is a DES-like Substitution-Permutation Network crypto system. It supports the length between 40 to 128 bits.

**Download** Five Models of Symmetric Key Algorithm CSE Seminar Idea for Final Year Students.