BY NIKHIL NARAYANAN
Hey, everyone! I’m Nikhil Narayanan- an individual JAVA SWING/AWT dev, and today
we’ll be talking about a program to convert plain text into a string unreadable by others,
which can be reformatted into the original text. In other words, an encryption algorithm
[Note: This is more of a shuffle algorithm than an industry-standard encryption algorithm
and is susceptible to reverse engineering. This text encryption algorithm is more of a fun
little side project than a guarantor of privacy]
What exactly does this program do, you might ask? Simple, really- it reads the ASCII
values of each character in the string inputted by the user and just, well- plays around
with the values. Think about it for a second, the ASCII value for the space character is
32, right? Now boost that value up by a random number between 8000 to 22000, say
9000- the said ASCII value now becomes 32+9000=9032 i.e ‘⍈.
Now, what if we took in a string and boosted each character in the string by 9000?
Sample String: “MAD SUS!”
Boosted String:”⍵⍩⍬⍈⍻⍽⍻⍉”
Boost Value/key: 9000
Now, simply subtracting 9000 from each character’s ASCII value in the boosted string,
we get the original string. Of course, such an encryption standard is trivially easy to
break/reverse engineer, but it gets my point of playing around with ASCII values to render
text unreadable across.
Encryption routine in it’s simplest form:
public static String encrypt(String s, int boost)
{
String ss=””;
for(int k=0;k<s.length();++k)
{
char ch=s.charAt(k);
ch+=boost;
ss+=ch;
}
System.out.println(ss);
return ss;
}
Of course, we can spice things up a bit- instead of adding up values to each character in
the string, we can subtract a random value(say, between 20 and 40) from alternate
characters in the string.
Now, we have a string with characters at odd positions boosted by say, 9000 and
characters at even positions subtracted by say, 30.
Input String: “MAD SUS!”
Boost value: 9000
Decrement value: 30
Encrypted String:”/⍩&⍈5⍽5⍉”
To reverse the conversion, we simply need the boost value and decrement value, which
will be used as keys- characters at even positions will be boosted by the decrement
value and characters at odd positions will be decremented by the boost value.
Of course, to increase the complexity a bit, other conversions can be factored in, such
as breaking the string into two parts at a random position and reversing one part(the first
half), then adding both strings back together, increasing the complexity of reverse
engineering the algorithm and simultaneously adding a third key to the algorithm.
Final Encryption Routine:
public static String encrypt(String s, int boost, byte decrement, int pos)
{
String ss=””;
for(int k=0;k<s.length();++k)
{
char ch=s.charAt(k);
if(k%2!=0)
ch+=boost;
else
ch-=decrement;
ss+=ch;
}
//Split the string into 2 parts
String a1=ss.substring(0,pos);
String a2=ss.substring(pos);
//reverse the first half
a1=new StringBuffer(a1).reverse().toString();
ss=a1+a2;
System.out.println(ss);
return ss;
}
Final Decryption Routine:
public static String decrypt(String s, int boost, byte decrement, int pos)
{
String ss=””;
String a1=s.substring(0,pos);
String a2=s.substring(pos);
//reverse the first half to bring it back to its original state
a1=new StringBuffer(a1).reverse().toString();
s=a1+a2;
for(int k=0;k<s.length();++k)
{
char ch=s.charAt(k);
if(k%2!=0)
ch-=boost;
else
ch+=decrement;
ss+=ch;
}
System.out.println(ss);
return ss;
}
Input text: “That’s mad sus!”
Boost value:10000
Decrement value:40
position key: 3
encrypted text: 9❸,➄ ➃❽9❴➃M➃
decrypted text: That’s mad sus!
As you can see, simple manipulations of ASCII values render the text unreadable to the
human eye. As mentioned earlier, the algorithm can be brute-forced/reverse engineered
with encrypted text to decrypted text comparisons, and is not industry standard-it’s still a
great example of how simple manipulations of ASCII values can reflect on the original
string.
Hope you enjoyed reading the article on how my shuffle cipher works- if you’d like to test
out the software, it’s available on my website(for pc and mobile).
here’s the link:
https://l.instagram.com/?u=https%3A%2F%2Fwww.swingguiking.com%2Fmy-work-
2&e=ATN9tZzA5-
NSqHOLB3o4HxLSjh9gflpPN7dVeXpGt0yUvxg5MzJUEN_1HCbzI2bctW6PDbUbqHX5s
3sTj1P_AraWngXqIntw7Mc9mA&s=1
If you like my work or other articles, feel free to contact me on Instagram
@nikhil.iscoding!
Good day!
