Hash  
Description
Converts a variable-length string to a 32-byte, hexadecimal string, using the MD5 algorithm. (It is not possible to convert the hash result back to the source string.)
 
Returns
32-byte, hexadecimal string
 
Category
Conversion functions, Other functions, String functions
 
Function syntax
Hash(string)
 
Parameters
 
Parameter      Description
string A string or a variable that contains one.
 
Usage
The result is useful for comparison and validation. For example, a developer can store the hash of a password in a database without exposing the password. The developer can check the validity of the password with the following code:
<cfif hash(form.password) is not myQuery.passwordHash>
  <cflocation url = "unauthenticated.cfm">
</cfif>
 
Example
<!--- How to use Hash for password validation. This assumes that UserID 
value is passed to this page with a URL parameter. --->
<h3>Hash Example</h3>

<cfquery name = "CheckPerson" datasource = "UserData">
   SELECT PasswordHash
   FROM SecureData
   WHERE UserID = <cfqueryparam value = "#UserID#"
      cfsqltype = "CF_SQL_CHARVAR"> 
</cfquery>

<cfif Hash(form.password) is not checkperson.passwordHash>
  <cflocation url = "unauthenticated.cfm">
<cfelse>
   ...
</cfif>
string  
A string or a variable that contains one.