Cryptography is derived from the Greek, is composed of two syllables are crypto and Graphia. Crypto means to hide, while the meaning Graphia writing. Cryptography is the study of mathematical techniques related to aspects of information security, such as data confidentiality, data authenticity, data integrity, and authentication of data .But not all aspects of information security can be solved by cryptography.
Cryptography can also be interpreted as a science or art to maintain the security of the message.
In principle, Cryptography has four main components:
Plaintext, which is a message that can be read
Ciphertext, that message can be read randomly tidka
Key, which is the key to perform cryptographic techniques
Algorithm, which is a method to perform enkrispi and decryption
Then, the process will be discussed in this article includes two basic processes in Cryptography, namely:
encryption
decryption
with the same key is used for both of the above processes. The use of the same key for both encryption and decryption process is also called the Secret Key, Shared Key or Key symetric cryptosystems.
Here is an illustration of the 4 components and 2 processes used in cryptography techniques.
encryption
Encryption is a process of making a message readable (plaintext) into a random message unreadable (ciphertext). Here is an example of encryption used by Julius Caesar, by replacing each letter with the letter next 3 (also called Additive / Substitution Cipher):
decryption
Decryption is the reverse process of encryption where the process is going to change the ciphertext into plaintext by using algorithms 'inversion' and the same key.
