"Cryptoy", a free application that lets you learn ciphers happily with a sense of game published by government intelligence agencies

When I hear "cryptography", I have a hard image, but I think that the application "CryptoyIn the UKGCHQHas been released. Cryptoy was released for Android, even junior high school students understand the basic principle of encryption technology and it is said that it is an application that you can make your own encrypted message, so I actually installed and used it.

Cryptoy - Android application on Google Play
https://play.google.com/store/apps/details?id=com.hmg.cryptoy

Open the above URL and tap "Install".


Tap "I agree".


After installing, tap "Cryptoy" icon and start it up.


Tap the screen once.


As the tutorial begins, tap "Skip".


This is the Cryptoy home screen. The screen displays "Shift (Caesar cipher) "Is displayed and when you swipe up from the bottom ... ....


You can learn the outline and history of Caesar encryption. Caesar cipher is a military leader of ancient RomeJulius CaesarIt is a cryptogram used for the first time, encrypting characters by shifting them in lexicographic order.


Since I do not know well even if I read it, tap "Start" and try to actually create a cipher using Caesar cipher.


You can select "Encypt" or "Decrypt", but this time, you select "Encypt".


Enter the word or sentence you want to encrypt and tap "Next".


A list in which the alphabets are arranged in two rows and "Encryption key A" are displayed in the center of the screen. If you look closely, there is "A" under "A" in the list and "H" under "H". At the bottom of the screen you will see "HELLO" for the word you entered.


Swipe the screen to the left and the second row of the list moves to the left. When "H" is matched to "A", "H" is changed to "O". The original word is encrypted from "HELLO" to "OLSSV". Caesar cipher is a technology to encrypt characters by shifting their letters alphabetically. That is, encrypting "HELLO" with the encryption key "H" will result in "OLSSV".


This time, if O is matched to A and encrypted with the encryption key "O", it becomes "VSZZC". Even if I read the overview, I did not know exactly what the Caesar crypto is, but when I actually experience encryption, it will be "Oh, that kind of thing". After enjoying encryption, tap "Done" at the end.


The original "Hello" and "VSZZC" encrypted with the encryption key "O" using the Caesar code are displayed.


Next challenge to decrypt Caesar encryption.


Decrypt "olssv" which encrypted "Hello" with encryption key "H" and verify whether it returns to the original.


Although it is decrypted with the encryption key A, it remains "OLSSV" ... ...


When decrypting with the encryption key H, it becomes "HELLO". Clicking "DONE" ...


The original "OLSSV" and the decrypted "HELLO" are displayed. I feel that I understand more about Caesar cryptography by encrypting and decrypting with my own hand.


Next is "Vigenère (Visionel cipher) "I will try it. Tap "Start".


Tap "Encrypt".


Enter the word or sentence you want to encrypt and tap "Next".


When you enter "Apple" as "Keyword", the original message "GIGAZINE" was converted to "GXVLDICT". I can not understand why this happened, so tap "Analysys" and check the details.


"GIGAZINE" before encryption from the left, "GXVLDICT" after encryption, "APPLEAPP" encryption key is displayed. "APPLE" is "APPLEAPP" because GIGAZINE is 8 characters, APPLE is 5 characters. It is the first letter of each boldface and the lower table to pay attention. The letter that "G" of "GIGAZINE" and "A" of "Apple" overlap in the table is "G". In other words, you can see that the VisiNell cipher is a mechanism to convert the original message and the encryption key into a character that matches in the table.


By swiping the bar on the screen from left to right you can check the encryption of the next letter. "I" is encrypted to "X" ...


"Z" is converted to "D". I understand the mechanism of the visionel cryptosystem that seems difficult to understand at first glance. Finally tap "Done" ......


You can see the original message and the encrypted message.


In Cryptoy, in addition to the above, "Substituion (Substitution type cryptography) "Or ...


Nazi · Germany used in World War II "Enigma (EnigmaYou can actually experience the encryption and decryption of a total of 4 types of encryption such as ".


Because Cryptoy is made for the learning of junior high school students, UI is fairly easy to understand and you can easily experience encryption and decryption without knowledge of English. It seems that it can be used as a simulator of encryption, so it may be a good idea to send an encrypted message to a friend. In addition, Cryptoy is released only for Android version applications, and for iOS it is not at the moment. Also, since it was not possible to confirm the operation with the smartphone even in the Android version, it is reviewed with Nexus 9. According to the product page, the product test is done only on Nexus 7 and Nexus 10, and it seems that it can not be confirmed without installing whether to operate on other terminals.