Скачать или смотреть Make Caesar Cipher More Secure

Make Caesar Cipher More Secure

steps:
watch previous videos

Simple Encryption App with Thunkable X
   • Simple Encryption App with Thunkable X  

Simple Encryption and Decryption App with Thunkable X
   • Simple Encryption and Decryption App with ...  

from the previous videos you will learn how to make a simple encryption and decryption with Caesar Cipher. now we will make the cipher more secure.

in the previous videos we can only encrypt alphabet (that later will be changed to uppercase. what if we want to encrypt both lowercase and uppercase alphabet? what if we want to encrypt numbers? can we encrypt a sentence with whitespace in between words? can we encrypt symbols?

because the code we have built is well constructed, we only need to modify ONE line to be able to make this cipher more secure and be able to encrypt and decrypt more symbols :)

let me show you ;)

we don’t change the design so we can skip this part
Design:
*notes: i assume that you can find your own ways about layout and component setting or i probably will make a tutorial about layout if needed ;)
1. add label and textfield for plaintext
2. add label and textfield for key (on the advanced tab, set the keyboard to numeric)
3. add label and textfield for ciphertext
4. add button for encrypt
5. add button for decrypt
6. i added a button for clearing the textfields to start doing encryption and decryption

Blocks:
*notes: click on the components on the left side to see what block you can use to perform action on the specific component

the pseudocode (the added lines of code is printed in different color):

and we only add this one line (the rest of the code is the same). the cipher will be more secure because now it has more possibilities of ciphertext because we have more characters and symbols in the character set:
alphanumeric = “abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890 ~`!@#$%^&*()_+{}|[]\:";'?,./”
key = 0
ciphertext = “”

when btnEncrypted Click do{
txtCiphertext = caesarCipher(txtPlaintext, key)
}

when btnDecrypted Click do{
txtCiphertext = caesarCipher(txtCiphertext, (lengthof(alphanumeric) - (key mod lengthof(alphanumeric)))
}

when btnClear Click do{
txtPlaintext = “”
txtCiphertext = “”
texKey = “”
}


char_plaintext = “”
char_ciphertext = “”
index = 0
char = “”
check = 0

caesarCipher(plaintext, text){
ciphertext = “”
if (key bigger than lengthof(alphanumeric)){
key = check mod length(alphanumeric)
}
plaintext = UPPERCASE(plaintext)
for i=1 to lengthof(plaintext) by 1{
char_plaintext = plaintext[i]
for x=1 to lengthof(alphanumeric) by 1{
char = alphanumeric[x]
if char == char_plaintext do{
index = x
break
}
}

check = index + key
if (check bigger than lengthof(alphanumeric)){
check = check mod lengthof(alphanumeric)
}

char_ciphertext = alphanumeric[check]
ciphertext = ciphertext + char_ciphertext
txtCiphertext = ciphertext
}
return txtCiphertext
}


click live test and open Thunkable App on your smartphone, and see how it works :)

in the next tutorial, we will learn how to do encryption and decryption with different algorithm ;)

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hope the tutorial is helpful, please leave comments to let us know what you think ;)