encrypt

Type

command

Summary

Encrypt data using a cipher.

Syntax

encrypt <source> using <cipher> with {password|key} <passorkey> [and salt <saltvalue>] [and IV <IVvalue>] [at <bitvalue> bit]

Description

The encrypt and decrypt commands accept the source data that will be encrypted or decrypted. The cipher is the name of the cipher obtained using the ciphernames function. The passorkey specifies the password or key that will be used for encryption or decryption as determined by the keyword before it. If you specify key then the key needs to be the same size (in bits, eight per byte) as the specified cipher key length. The key may optionally be accompanied by the IVvalue used by some ciphers. If you specify password or don't specify a key mode, then a password, typically text, will be used. The password may optionally be accompanied by a saltvalue. The bitvalue specifies the key length in bits (for example, 64, 128, 192 or 256) and may be zero or empty for the default length (that is listed with the cipherNames function). Some ciphers have fixed key lengths and using an unsupported value will result in an error.

The key and IV value are the fundamental determiner in block ciphers. The IV value is typically the width (in bits) of the block associated with the cipher. The default value is zero. Its use is beyond the scope of this documentation.

The password and salt value are combined and scrambled to form the key and IV which are used as described above. The key derivation process is the same as that used in the openSSL utility. A 16-byte salt prefix is prepended to the encrypted data, based on the salt value. This is used in decryption. If no salt value is specified for a password, one is randomly generated. The use of a randomized salt value is a protection against dictionary attacks.

Some modes of block ciphers will pad data to be a multiple of block size. The padding method is that used by the openSSL utility and is a minimum of one byte.

Parameters

Name	Type	Description
source		the source input data
cipher		the format used to encrypt the data
passorkey		a password or key provided to the encryption routine, as necessary
saltvalue		the password may also be accompanied by a salt value
IVvalue		An IV (initialization vector) value may be specified for some cipher methods
bitvalue		the bit value specifies the key length in bits (ie. 64, 128, 192, 256, etc)

Examples

-- the following copies a file from disk, stores it in a variable (myData), encrypts the result,
-- then copies the file back to disk.

local path2input, myData, path2output
-- put the file path to your input and output files into path2input and path2output
put URL ("binfile:" & path2input) into myData 
encrypt myData using "aes-256-cbc" with password "@&^2fy" 
put it into URL ("binfile:" & path2output) 

Related

command: decrypt

function: cipherNames

property: sslcertificates

Compatibility and Support

Introduced

LiveCode 2.5

OS

mac

windows

linux

ios

android

Platforms

desktop

server

mobile