Php xor encrypt decrypt

A correct usage example is actually pretty long and needs a lot of explanation, so I developed a safe wrapper library which doesn't constrain usage and which comments itself very heavily. It's appropriate for use or for learning. You must use true random number generator.

Only keys of size 16 supported in script. I tried to implement the mcrypt with rijndael For reference I took the code from example 1 and tried running that first, but on the decryption part came back with the error: "The IV parameter must be as long as the blocksize". To work around that, before merging the IV and the encrypted text, I added null padding to match the IV size. This is a solution for the 3DES algorithm's problem in his interaction with.

Cryptography , CBC mode, because the key is completed to bits and the text is padded. So, we has two problems: - The key's completion was posted by "jesse at pctest dot com".

The padding bytes are 0x01 to 0x08 because completed to 8 bytes blocks. If your text have a whole number of 8 bytes blocks, the algorithm add other block with padded bytes 0x If you use vast key as long as encrypted message which is random space noise recorded on a cd , the encrypted message is also radnom - impossible to decrypt without key.

Under those conditions, XOR is strongest encryption algorithm ever known. XOR encryption only works if the key is at liest the same size as the plaintext, and the key is perfectly random. And no, rand is not perfectly random. The logical XOR can be used for encrypting data. The encrypt function below takes two strings, a plaintext message and a key. This result is then converted into a 8 bit binary value, and then converted to a two digit hexadecimal value and appended to a string, which is what we will return.

The decrypt function also takes two strings, the encrypted message in form of a string of hexadecimal values , and the key. First of we split the encrypted message into an array of two digit hexadecimal values. We then loop over this array. For each position in the array we convert the hexadecimal value to a character and XOR it with the corresponding character in the key. The character is then appended to a string, which is what we will return afterwards. This operand will compare two bits and will produce one bit in return.

That bit will be equal to 1 if the two compared bits were different, 0 if they were equal. Xor encryption is commonly used in several symmetric ciphers especially AES. A symetric cipher is simply a cipher in which the key is used for xor encryption and decryption process. The XOR operand is so applied to each bit between the text you want to encrypt and the key you'll choose.