Cryptography (cryptography) comes from the Greek language, consisting of two syllables, namely crypto and Graphia. Crypto means hiding, while graphia means writing. Cryptography is a science that learns mathematical techniques related to information security aspects, such as data confidentiality, data validity, data integrity, and data authentication. But not all aspects of information security can be solved by cryptography.

Cryptography can also be interpreted as a science or an art to keep messages safe.
In principle, cryptography has 4 main components:
– PlainText, which is a readable message
– Ciphertext, which is a random message that can be read
– Key, ie the key to conducting cryptographic techniques
– Algorithm, which is method to perform encryption and decryption
Then, the process that will be discussed in this article includes two basic processes on cryptography namely:

Encryption
Decryption

With the key used the same for both processes above. Using the same key for both encryption and decryption processes is also called Secret Key, Shared Key or Symetric Key Cryptosystems.

The equipment is the equipment used for the activities of the work and is a tool that must be used when we want to do the activities, the application is divided into 2 instruments, namely, hardware or hardware and devices Software. Hardware and software is a very related thing in this paper will be explained about a software that can be used for the activity of the application of CrypTool

CrypTool is an open source application created by a team from the University Of Kassel Germany, the team contains professors who are in the world of technology. This software is specially made in addition to the use of kriprtography but as a means of learning the activities of the training especially for students engaged in technology or practitioners Itdue to this software not only limited encryption and Description but also described the encoding mechanism and the algorithm used.

FEATURE?

Cryptool 2 has approximately 300 algorithms that can be used and is very complete cryptographic and cryptotanalisis software, many people assume that this application is a modern cryptographic machine that is practicable in the form of Software that has a variety of features that quite a lot include:
1. Well-known classical cryptography available such as Caesar, Enigma, Solitaire, XOR, Tranposition, Hill Cipher and more
2. In addition to classical cryptografui of course CrypTool 2 also provides a variety of modern cryptography tools both symmetrical and asymmetrical, for symmetrical examples such as DES, AES, SDES, Camellia and others. As well as for the asymmetric example of RSA, RSA Key Generator and other still.
3. Interestingly apart from cryptographic features, this software also has a feature in the case of steganography covering the permutation, insertion and the fabric
4. There is also a device simulation
5. Other than that another pretty cool feature that is cryptotanalisin or science to crack the password or data, in this application used several algorithms to solve a password or encrypted data such as prime test method, Seracher key, Enigma, Cube attack, Factorizer and more
6. The next feature is the interface of the Cryptool application which is very visual and can be adjusted as desired based on the parameters in the application

In this application, there are many features of cryptographic and even steganography. Cryptool is a very suitable application for the students or practitioners of the technology world in learning cryptography. Because in the software or applications it has a lot of cryptographic features and easy to understand and Provides a view of how the cryptographic process is running so as to facilitate the user in understanding any algorithm or system in the processing activity or cryptography.