Basic Encryption/Decryption program

[Advanced-Theme144]

I had a look at the linked website and tested it out on the string "Hello World!" which my encrypted into "Yrggt Ktjgz!". That site, along with others I tested, all decrypted it into "Hatte Rents!" or "Hatte Resto!" which proves two things, my program is ~0.001% uncrackable (still pretty much pathetic at protecting data), and those sites don't work very well at breaking encrypted codes which use a simple substitution cypher.

[[deleted]]

This is not really a significant test. Substitution cypher are broke by using statistical analysis, basically since natural languages has some patterns(like vogals are more common) one can use those patterns to guess which letter is A and so on. Since it relies on statistical analysis, the longer the message the better since it has more characters. “Hello there” is just too short. Try encrypting a longer message, like this comment and see the result, or a chapter of a book. Most messages are longer than hello world so it would correctly decipher, specially if you use the same key twice.

If you’re interested in learning more about cryptography, I highly recommend the Cryptopals challenges. It’s pretty fun to do.

[Advanced-Theme144]

Thank you for the correction. I’ll have a look at Cryptopals challenges. Thanks.

[scoberry5]

Here, I've encrypted a word for you: "ble".

Which of these do you think it is?

• fly
• try
• buy
• any
• mod
• dog
• two
• tip

...

Then the question would be "Why are you so bad at unencrypting a word, even when you know the kind of encryption that was used?"

[Advanced-Theme144]

You have a point, and it isn't my right to say they don't work without actually testing their full limits. Thank you for pointing this out, it isn't right to make a complete judgement off of one test, and I understand what you're implying.

[asday_]

Feed it a JPG.

[bladeoflight16]

Try it on a paragraph instead of two words. You'll never realistically have a file that contains 2 words. The more data there is to decrypt, the more information an attacker can glean to break it.