Crypto.MD5DigestFromString Examples

OverviewExamples

string Crypto.MD5DigestFromString (

string Text )

Example 1

-- Calculate the MD5 message digest for the user's name and display it in a message

strName = Dialog.Input("", "What is your name?", "", MB_ICONQUESTION);

strDigitalSignature = Crypto.MD5DigestFromString(strName);

Dialog.Message("The digital signature for your name is:",strDigitalSignature);

Prompts for the user's name and then generates the MD5 message digest for it and shows it in a dialog message.

Example 2

--[[ note: our app allows the user to password-protect it. If the user

chose to enable password-protection, they were prompted for

a password, we appended a suffix to it (to help prevent

dictionary attacks), and the MD5 digest for the resulting

password + suffix was stored in the Registry.]]

--[[ get the digest that was stored in the Registry at HKEY_CURRENT_USER\Software\SuperDooperApp

note: this was calculated when the user supplied the password,

before it was stored ]]

reg_md5 = Registry.GetValue(HKEY_CURRENT_USER, "Software\\SuperDooperApp", "password")

-- the value only exists when the app is password-protected

if reg_md5 ~= "" then

--[[ ask the user for the password they supplied when they enabled

the password protection feature ]]

pw = Dialog.Input("", "Please enter your password:");

--[[ we added "!$" to their password before it was stored,

to help make the user's password safe from dictionary attacks ]]

pw = pw .. "!$"

-- calculate the MD5 message digest for the password + suffix

pw_md5 = Crypto.MD5DigestFromString(pw);

-- exit the app if the password digests don't match

if pw_md5 ~= reg_md5 then

Dialog.Message("", "Sorry, invalid password!");

Application.ExitScript();

end

Given that the MD5 message digest for a password was previously stored in the Registry, a user is prompted for the password and it is compared to the current password input from the user. If the message digests do not match, the application exits.