Polybius cipher

Polybius cipher is a basic form of encryption invented by the Ancient Greek Historian whose name it bears. It is based on fractionating plaintext characters so they can be represented by a smaller set of symbols. In plain English: all the letters of the alphabet are written in a 5×5 square like the one below:

. . . → Read More: Polybius cipher

Vigenere cipher

Vigenere cipher is an encryption technique consisting of a sequence of Caesar cipher each based on the letters of a secret text called a keyword. This mechanism is classified as polyalphabetic substitution.

In Caesar substitution each letter was shifted a number of positions down the alphabet. For example choosing the secret key to be 5, . . . → Read More: Vigenere cipher

HTTP or HTTPS, find out if the page is secure in PHP

Any site involving sensitive information needs to have some of its pages only accessible via SSL. This is a way to make sure that your page is only available on https, using the predefined variable $_SERVER['HTTPS'] to determine the connection and $_SERVER['SERVER_NAME'] and $_SERVER['REQUEST_URI'] to rebuild the accessed url:

1 2 3 4 5 if($_SERVER[’HTTPS’] . . . → Read More: HTTP or HTTPS, find out if the page is secure in PHP

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