Introduction
Encryption is the process of encoding a message or information in such a way that only authorized parties can access it and those who are not authorized cannot Decryption: The process of unlocking the encrypted information using cryptographic techniques Key: A secret like a password used to encrypt and decrypt information. There are a few different types of keys used in cryptography. An algorithm: is basically a procedure or a formula for. An encryption algorithm is a set of mathematical procedure for performing encryption on data. Through the use of such an algorithm, information is made in the cipher text and requires the use of a key to transforming the data into its original form.
Encryption types:
1-Symmetric.
2-Asymmetric.
Symmetric Encryption
Symmetric Encryption: This is the simplest kind of encryption that involves only one secret key to cipher and decipher information. Symmetrical encryption is an old and best – known technique. It uses a secret key that can either be a number, a word or a string of random letters. It is a blended with the plain text of a message to change the content in a particular way. The sender and the recipient should know the secret key that is used to encrypt and decrypt all the messages.
Some of Symmetric Encryption Algorithms:
Blowfish, AES, RC4, DES, RC5, and RC6.
1- The most widely used symmetric algorithm is: AES – 128, AES – 192, and AES – 256. 2- The main disadvantage of the symmetric key encryption is that all parties involved have to exchange the key used to encrypt the data before they can decrypt it.
Asymmetric Encryption
Asymmetric Encryption is also known as public key cryptography, which is a relatively new method, compared to symmetric encryption. Asymmetric encryption uses two keys to encrypt a plain text. A public key is made freely available to anyone who might want to send you a message. The second private key is kept a secret so that you can only know.
A message that is encrypted using a public key can only be decrypted using a private key, while also a message encrypted using a private key can be decrypted using a public key Security of the public key is not required because it is publicly available and can be passed over the internet. Asymmetric key has a far better power in ensuring the security of information transmitted during communication .
1- Asymmetric encryption is mostly used in day – to – day communication channels especially over the internet .
2- Popular asymmetric key encryption algorithm includes: ElGamal RSA, DSA Elliptic curve techniques, PKCS.
Symmetric Vs Asymmetric Encryption
1- Symmetric encryption uses a single key that needs to be shared among the people who need to receive the message while asymmetrical encryption uses a pair of public key and a private key to encrypt and decrypt messages when communicating.
2- Symmetric encryption is an old technique while asymmetric encryption is relatively new.
3- Asymmetric encryption was introduced to complement the inherent problem of the need to share the key in symmetrical encryption model, eliminating the need to share the key by using a pair of public – private keys.
4- Asymmetric encryption takes relatively more time than the symmetric encryption.
Asymmetric Encryption in Digital Certification
1- To use asymmetric encryption, there must be a way of discovering public keys, One typical technique is using digital certificates in a client – server model of communication. A certificate is a package of information that identifies a user and a server. It contains information such as an organization’s name, the organization that issued the certificate, the users’ email address and country, and users public key.
2- When a server and a client require a secure encrypted communication, they send a query over the network to the other party, which sends back a copy of the certificate. The other party’s public key can be extracted from the certificate. A certificate can also be used to uniquely identify the holder.
3- SSL / TLS uses both asymmetric and symmetric encryption.