IPSec (ESP, AH, DES, MD5, SHA, DH)

IPsec( Internet Protocol Security) is a protocol that secures Internet Protocol by authentication and encrypting each IP packet involved in a communication session. It operates in the Internet layer of the Internet Protocol Suite protecting data traffic between hosts and networks. It uses the various protocols such as Encapsulating Security Protocols, Authentication Headers and encryption technologies like Data Encryption Standard , MD5, Secure Hash Algorithm and Diffle-Hellman .

Encapsulation Security Protocols

It is a security protocol that provides data confidentiality, data source authentication, connectionless integrity. It also prevents anti-replay service (for e.g, someone log in with the credential used by other people to log into a system).

Authentication Header

Authentication Header is a member of the IPsec protocol suite that provides authentication, integrity and anti-replay for the entire data packet. Although it does not encrypt the data, it modifies the data using  HMAC algorithms to ensure its integrity  By doing so, one can ensure that the data is not altered without permission.

Data Encryption Standard

DES is a previously predominant encryption algorithm for electronic data. However, compared to today's encryption standards, is considered to be insecure due to its use of a 56-bit key. DES was developed to meet the  US government's computer security needs and through this, it jump started the study and development of encryption algorithms..

DES works by taking in a fixed-length string plaintext and turns it into a ciphertext of the same size as the plaintext data. As it uses a particular key to customize the encryption, only authorized people who knows the key can use it to decrypt.

MD5

MD5(also known as MD5 Message-Digest Algorithm) is widely used as a cryptography hash function to encrypt data. It has been employed in a wide variety of security applications and used for checking data integrity.

SHA

SHA also known as Secure Hash Algorithm is one of  the cryptography hash functions. There are 4 types of SHA invented and each is denoted with a number behind.

Diffle-Hellman 

Also known as DH. It is a method of exchanging cryptography keys which allows two parties (with no prior knowledge of the other party) to establish a shared secret key while using insecure communications channel. This key encrypts data communications with a symmetric key cipher.