Once upon a time, keeping data to be secret was not hard, but to keep them secret, you had to write them down and keep in such a way that it must be hidden from those people, whom we do not want to have visibility on our data sets.
Eventually, it did not take very long for ancient military leaders to create and use better techniques, ever since then encryption has been a process of using complex tactics to stay one step ahead of those who want your secret data.
A process that transforms a plain text message into ciphertext is called encryption, and decryption is the opposite of encryption, it transforms ciphertext messages back into plain text.
Plain Text: The original readable message.
Cipher Text: A coded message which is not understood by everyone.
When using cipher, the original information is known as plain text and the encrypted or coded form is called as ciphertext. The ciphertext messages contain all the information of the plain text messages but it is not in a readable format for a human but it can be decrypted only by using a computer or some mechanism. There are two methods of ciphertext.
Substitution Ciphers encrypt plaintext by changing the plain text one piece at a time. The Caesar Cipher is an example of a substitution cipher. In the Caesar Cipher, each character is shifted three letters up or you can say three places up. For example, S becomes V and B becomes E, etc… The following table shows “SIMPLE” word is encrypted by using a substitution cipher.
Transposition Ciphers encrypt plain text by moving small pieces of the message around each other. Anagrams are the example of Transposition Ciphers. The following table shows “RAINBOW” begin encrypted by using transposition ciphers.
Cryptography is the art of achieving security by encoding messages to make them non-readable.
Symmetric Key Cryptography:
In Symmetric-key cryptography, the same key is used by both parties. The sender uses a Secret key for sending the message the same Secret key used by the receiver to decrypt the message. For example, if Stella wants to send a message to Kelvin then Stella uses a key to encode the message and once the message is received by Kelvin the same key is used to decode the message.
Asymmetric Key Cryptography:
In Asymmetric-key cryptography, there are two different types of keys that are used by both parties. There are two keys: Public key and Private Key. The sender uses a key for sending the message and that key is announced as the public key and once the message is received by the receiver the person uses his own key which is announced as the private key. For example, if Stella wants to send a message to Kelvin then Stella uses a public key to encode the message and once the message is received by Kelvin he uses the private key to decode the message. This technique is more powerful than Symmetric key cryptography.