Here we are in 2017, the Technological era and most of our lives are spent using technology. We often wonder if our work on the internet is safe or not, this is where cryptography plays its role.
Cryptography is the science of providing security for information and resources by using appropriate technologies.
It can be used for non-technological reasons like hiding physical messages, or creating ciphers so that only you and your friends can read your messages, but nowadays it is used for more vital reasons. It is the basis for Data Encryption.
Cryptography is used to make sure all of the thingslisted above, butpeopleusually find loops holes or ways around the rules. Cryptography takes math and uses it to develop algorithms for computer systems to use to secure data either before data transfer or just for secure data storage.
It is the combination of encryption and decryption of anything (i.e. message, file etc.) This is very vast field around Information Security.
There are many cryptography algorithms mainly divided in two categories:
Asymmetric Key Cryptography and Symmetric Key Cryptography.
When Different keys are used for both encryption and decryption, it is known as Asymmetric Key Cryptography.
When same key is used for both encryption and decryption, it is known as Symmetric Key Cryptography.
The term cryptography has also expanded to include more than just the processes of encrypting and decrypting messages in order to hide messages from an outside observer. Cryptography allows us to form digital signatures, characterize a large message by a small message (or digest), and even more complex things like distributed currency.
Cryptography makes secure web sites and electronic safe transmissions possible. Due to the large number of commercial transactions on the internet, cryptography is very key in ensuring the security of the transactions.It allows you to have confidence in your electronic transactions. Encryption is used in electronic transactions to protect data such as account numbers and transaction amounts, digital signatures replace handwritten signatures or credit card authorizations, and public-key encryption provides confidentiality.
Cryptography is also used in access control to regulate access such as in satellite and cable TV. Without cryptography, hackers could get into our e-mail, listen in on our phone conversations, tap into cable companies ,acquire free cable service, or break into our bank/brokerage accounts.
Cryptography -among other things- tries to make sure that a message sent from you (your voice, your text, your email) can be understood only by the person that is intended to get that message.
Cryptography guarantees basic security services authorization, authentication, integrity, confidentiality, and non-repudiation in all communications and data exchanges in the new information society.
These guarantees are achieved as follows:
Confidentiality- through encryption
Authentication- through digital signatures and digital certificates
Integrity- through generating a digital signature with a public key and obtain the message digest, then hashing the message to obtain a second digest. If the digests are identical, the message is authentic and the signer’s identity is proven.
Non-repudiation- through digital signatures of a hashed message then encrypting the result with the private key of the sender, thus binding the digital signature to the message being sent.
Non-replay– through encryption, hashing, and digital signature