Cryptographic algorithms are used for important tasks such as data encryption, authentication, and digital signatures.

1. Cryptographic
Algorithms
Mrs.G.Chandraprabha.,M.Sc.,M.Phil.,
Assistant Professor
Department of Information Technology,
V.V.Vanniaperumal College for Women,
Virudhunagar.

2. Cryptograpy:
The term is derived from the Greek word kryptos, which means hidden.
Cryptographic Algorithms:
Cryptographic algorithms are used for important tasks such as data
encryption, authentication, and digital signatures.

3. Encryption & Decryption
The process of converting plaintext into ciphertext.
 The process of converting ciphertext into plaintext.

4. Symmetric Encrption
 Symmetric encryption is an encryption methodology that uses a
single key to encrypt (encode) and decrypt (decode) data
There are five main components :
 plaintext
 encryption algorithm
 secret key
 Cipher text
 decryption algorithm

5. Symmetric Encrption
1. Plaintext
The term plaintext refers to the
original message that's created
and sent into the encryption
method
2. Encryption Algorithm
The encryption algorithm takes the plaintext and
converts it into an unreadable format.
3. Key
The key holds the information on all
the switches and substitutions
made to the original plain text.
4. Cipher text
The cipher text is the text that is now
scrambled and ready to be sent
5. Decryption Algorithm
Basically performing the encryption in reverse.

6. Two of the most common symmetric encryption
1. Data Encryption Standard (DES) :
 The algorithm takes the plain text in 64-bit blocks and converts them into cipher text using 48-
bit keys.
 Smart cards
 SIM cards
 Modems
 Routers
 Set-top boxes

7. 2. Advanced Encryption Standard (AES). :
AES based on the Rijindael algorithm, which was developed by Rijmen and Jone Daemen.
The features of AES are as follows −
 Symmetric key symmetric block cipher
 128-bit data, 128/192/256-bit keys
 Stronger and faster than Triple-DES
 Provide full specification and design details
 Software implementable in C and Java

8. Asymmetric Encrption
 Asymmetric Encryption consists of two cryptographic keys known as Public Key and
Private Key.
 Asymmetric Encryption (also known as asymmetric cryptography) allows users to
encrypt information using shared keys
 Diffie-Hellman
 ECC

9. Encrption Key Size:
 When deploying cipher ,it is important for user to decide on the size of the
crypto variable or key, because the strength of many encryption
applications and crypto system Is measured by key size.
 The length of the key increases the number of random guesses that have
to be made in order to break the code.
 Creating a larger universe of possibilities increase the time required to
make guesses, and thus a longer key directly influences the strength of
the encryption.