Digital Signature:
1. Digital signatures are based on asymmetric cryptography and can provide assurances of evidence to origin, identity and status of a; electronic document, transaction or message, a well as acknowledging informed by the signer.
2. To create a digital signature, signing softwar- (email) creates a one-way hash of the electron data to be signed. The user's private key tencrypt the hash, returning a value that is unit to the hashed data.
3. The encrypted hash, along with other information such as the hashing alqorithrn, forms the digital signature. Any change in the data, even to a single bit, results in a different hash value. This attribute enables others to validate the integrity of the data by using the signer's public key to decrypt the hash.
4. If the decrypted hash matches a second computed hash of the same data, it proves that the data hasn't changed since it was signed. If the two hashes don't match, the data has either been tampered with in some way (indicating a failure of integrity) or the signature was created with a private key that doesn't correspond to the public key presented by the signer (indicating a failure of authentication).

Firewall Server:
A firewall is a computer network security-based system that monitors and controls the incoming and outgoing network traffic based on predefined security rules. A firewall commonly establishes a block between a trusted internal computer network and entrusted computer outside the network.
They are generally categorized as network-based or host-based.
1. Network-based firewalls are positioned on the gateway computers of LANs [local area Network], WANs [Wide Area Network], and intranets,
2. Host-based firewalls are positioned on the network node itself. The host-based firewall may be a service as a part of the operating system or an agent application such as endpoint security or protection.

HACKING:
Hacking is intruding into a computer system to steal personal data without the owner's permission or knowledge (like to steal a password). It is also gaining unauthorized access to a computer system, and altering its contents. It may be done in pursuit of a criminal activity or it may be a hobby

Digital signature :
(i) Digital signatures are based on asymmetric cryptography and can provide -assurances of evidence to origin, identity and status of an electronic document, transaction or message, as well as acknowledging informed by the signer.
(ii) To create a digital signature, signing software (email) creates a one-way hash of the electronic data to be signed.
(iii) The user's private key to encrypt the hash, returning a value that is unique to the hashed data. The encrypted hash, along with other information such as the hashing algorithm, forms the digital signature. Any change in the data, even to a single bit, results in a different hasp value.

(iv) This attribute enables others to validate the integrity of the data by using the signer's public key to decrypt the hash. If the decrypted hash matches a second computed hash of the same data, it proves that the data hasn't changed since it was signed.
(v) If the two hashes don't match, the data has either been tampered with in some way (indicating a failure of integrity) or the signature was created with a private key that doesn't correspond to the public key presented by the signer (indicating a failure of authentication).

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