DecryptBinary

Description

Decrypts encrypted binary data with the specified key, value, algorithm, salt, and iterations.

Returns

Unencrypted binary data.

Function syntax

DecryptBinary(bytes, key[, algorithm[, IVorSalt[, iterations]]])

History

ColdFusion MX 7 Updater: Added the function.

Parameters

Parameter	Description
bytes	Binary data to decrypt.
key	String. For the CFMX_COMPAT algorithm, the seed that was used to encrypt the binary data; for all other algorithms, the string generated by the `generateSecretKey()` method.
algorithm	(Optional) The algorithm to use to decrypt the data. Must be the same as the algorithm used to encrypt the binary data. ColdFusion MX installs a cryptography library with the following algorithms: CFMX_COMPAT: the algorithm used in ColdFusion MX and prior releases. This algorithm is the least secure option (default). AES: the Advanced Encryption Standard specified by the National Institute of Standards and Technology (NIST) FIPS-197. BLOWFISH: the Blowfish algorithm defined by Bruce Schneier. DES: the Data Encryption Standard algorithm defined by NIST FIPS-46-3. DESEDE: the "Triple DES" algorithm defined by NIST FIPS-46-3. If you install a security provider with additional cryptography algorithms, you can also specify any of its string encryption and decryption algorithms.
IVorSalt	(Optional) Specify this parameter to adjust ColdFusion encryption to match the details of other encryption software. If you specify this parameter, you must also specify the `algorithm` parameter. For Block Encryption Algorithms: This is the binary Initialization Vector value to use with the algorithm. The algorithm must contain a Feedback Mode other than ECB. This must be a binary value that is exactly the same size as the algorithm block size. For Password Based Encryption Algorithms:- This is the binary Salt value to transform the password into a key.
iterations	(Optional) The number of iterations to transform the password into a binary key. Specify this parameter to adjust ColdFusion encryption to match the details of other encryption software. If you specify this parameter, you must also specify the `algorithm` parameter with a Password Based Encryption (PBE) algorithm. Do not specify this parameter for Block Encryption Algorithms. You must use the same value must to encrypt and decrypt the data.

Usage

This function uses a symmetric key-based algorithm, in which the same key is used to encrypt and decrypt data. The parameter values must match the values used to encode the string. The security of the encrypted string depends on maintaining the secrecy of the key.

ColdFusion MX 7 Updater uses the Java Cryptography Extension (JCE) and installs a Sun Java 1.4.2 runtime that includes the Sun JCE default security provider. This provider includes the algorithms listed in the Parameters section. The JCE framework includes facilities for using other provider implementations; however, Macromedia cannot provide technical support for third-party security providers.

Example

<h3>DecryptBinary Example</h3>
< !--- Do the following if the form has been submitted. --->
<cfif IsDefined("Form.myfile")>
<cffile file="#Form.myfile#" action="readBinary" variable="myData">
<cfscript>
/* GenerateSecretKey does not generate key for the CFMX_COMPAT algorithm,
so use the key from the form.
*/
if (Form.myAlgorithm EQ "CFMX_COMPAT")
theKey=Form.MyKey;
// For all other encryption techniques, generate a secret key.
else
theKey=generateSecretKey(Form.myAlgorithm);
//Encrypt the string
encrypted=encryptBinary(myData, theKey, Form.myAlgorithm);
//Decrypt it
decrypted=decryptBinary(encrypted, theKey, Form.myAlgorithm);
</cfscript>
<cfset encfile="#Form.myfile#" & "_enc">
<cfset decfile="#Form.myfile#" & "_dec">
<cffile file="#encfile#" action="write" output="#encrypted#">
<cffile file="#decfile#" action="write" output="#decrypted#">
<!--- Display the values used for encryption and decryption, 
and the results. --->
<cfoutput>
<b>The algorithm:</b> #Form.myAlgorithm#<br>
<b>The key:</B> #theKey#<br>
<br>
<b>The InputFile:</b> #Form.myfile# <br>
<br>
<b>Encrypted:</b> #encfile#<br>
<br>
<b>Decrypted:</b> #decfile#<br>
</cfoutput>
</cfif>
<!--- The input form. --->
<form action="#CGI.SCRIPT_NAME#" method="post">
<b>Select the algorithm</b><br>
<select size="1" name="myAlgorithm">
      <option selected>CFMX_COMPAT</option>
      <option>AES</option>
      <option>DES</option>
      <option>DESEDE</option>
</select><br>
<br>
<b>Input your key</b> (used for CFMX_COMPAT encryption only)<br>
<input type = "Text" name = "myKey" value = "MyKey"><br>
<br>
<b>Enter filename to encrypt</b><br>
<input type="text" name="myfile" value="Enter the path of the file to encrypt"><br>
<input type = "Submit" value = "Encrypt file ">
</form>

Version 7

Send me an e-mail when comments are added to this page | Comment Report

Current page: http://livedocs.adobe.com/coldfusion/7/htmldocs/00001829.htm