Encryption and Description on Data Secure

        Encryption is the process of securing the information by making the information can not be read without the aid of special knowledge. In another definition Encryption is a process of encoding the data to prevent unauthorized viewing or modify it. Encryption is a process to convert plaintext into chiperteks.Planteks itself is the original data or messages to be sent, while the ciphertext is the result of data encryption.

      Encryption is used to protect critical data and prevent the unauthorized access to important documents. Encryption called cryptography, which is a science that created a message that can only be read by the sender and the receiver.

     Decryption is the process of taking encoded or encrypted text or other data and converting it back into text that you or the computer are able to read and understand. This term could be used to describe a method of un-encrypting the data manually or with un-encrypting the data using the proper codes or keys.

The purpose of encryption is as follows:

Confidentiality

To keep the contents of the information of anyone other than who has the authority or the secret key to unlock the encrypted information.

Integrity

To maintain the authenticity / integrity of  data, the system must have  ability to detect manipulation data by parties who are not entitled, such as insertion, deletion, and other substitution data into the actual data.

Authentication

This relates to identification / recognition, both of  unity and  information system itself. Two parties must communicate with each other to introduce themselves. Information transmitted through a channel should be authenticated authenticity, data contents, delivery time, and others.

  

Three categories of Encryption :

• Secret encryption key, there is a key to encrypt and decrypt the once information.  
• Public encryption key, there are two keys, one for encryption, and one for decryption process. 
• One-way Functional, information on encryption to create a "signature" of the original  information   used to authenticate.

Advantages of Encyption : 

•  Confidentiality of information guaranteed.
•  Provide authentication and integrity protection in the check sum algorithm.
•  Tackling phone tapping and email. 
•  For digital signature

Disdvantages of Encyption : 

• Encryption terrorist plot 

• Concealment of a criminal record by a thief.

• Messages can not be read when the message recipient forgotten or lost key.

       Symmetric and asymmetric encryption uses two different algorithms to produce ciphertext. In symmetric encryption, algorithm will breaks down data into small pieces called blocks. Then it would replace the letters, change the information in each block into numbers, compresses and expands data, and then run it through a mathematical formula including the key in. Algorithm then repeats the process, sometimes until a dozen repetitions. On asymmetric encryption algorithm, treats the text as a very large figure, raises it to a larger number, and then calculates remainder after dividing by other third-largest number. Finally, this rest of the figure is converted to text back. Encryption program can use the same algorithm in different ways, which is why the recipient of  encrypted information must have the same program with sender for coding data they receive.

Example Encyption UNINDRA  with  MONOALPHABETIC key 4 :



Sources : Ikbal, I. Cyrptografi System Chapter XIII, UNIKOM
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