Description
Decrypts a string that is encrypted using a standard encryption technique, including strings encrypted by the Encrypt function.
Returns
An unencrypted string.
Category
Security functions, String functions
Function syntax
Decrypt(string, key, encoding, algorithm, IV_Salt, iterations)
See also
History
- ColdFusion (2023 release) Update 8 and ColdFusion (2021 release) Update 14: Changed the default algorithm from CFMX_COMPAT to AES/CBC/PKCS5Padding.
- ColdFusion (2021 release): Added support for authentication encryption.
- ColdFusion (2018 release): Introduced named parameters.
- ColdFusion 8: Added support for encryption using the RSA BSafe Crypto-J library on Enterprise Edition.
- ColdFusion MX 7.01: Added the IVorSalt and iterations parameters.
- ColdFusion MX 7: Added the algorithm and encoding parameters.
Parameters
Parameter |
Description |
|---|---|
encrypted_string |
String to decrypt. |
key |
String. For the CFMX_COMPAT algorithm, the seed that was used to encrypt the string; for all other algorithms, the string generated by the generateSecretKey() method. |
algorithm |
(Optional) The Enterprise Edition of ColdFusion installs the RSA BSafe Crypto-J library, which provides FIPS-140 Compliant Strong Cryptography. For a list of algorithms, see the Encrypt function.The Standard Edition of ColdFusion installs a cryptography library with the following algorithms:
Note: When using the algorithm: AES/GCM/NoPadding for this function, If you see the error- An error occurred while trying to encrypt or decrypt your input string: Tag mismatch!., either you could be using an incorrect salt or the value of the parameter iterations do not match the one used for encrypting the string. |
encoding |
(Optional; if you specify this parameter, also specify the algorithm parameter.) The binary encoding used to represent the data as a string. Must be the same as the algorithm used to encrypt the string.
|
IVorSalt |
(Optional) Specify this parameter to adjust ColdFusion encryption to match the details of other encryption software. If you specify this parameter, also specify the algorithm parameter.
|
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, also specify the algorithm parameter with a Password Based Encryption (PBE) algorithm. Do not specify this parameter for Block Encryption Algorithms. Use the same value 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 a string. The parameter values must match the values used to encode string . The security of the encrypted string depends on maintaining the secrecy of the key. ColdFusion uses the Java Cryptography Extension (JCE) and installs a Sun Java 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, Adobe cannot provide technical support for third-party security providers.
Example
<cfscript>
myInfo={};
myInfo.key = generateSecretKey("AES");
myInfo.secret = "my secret";
myInfo.encrypted=encrypt(myInfo.secret, myInfo.key, "AES", "Base64");
myInfo.decrypted=decrypt(myInfo.encrypted, myInfo.key, "AES", "Base64");
writeDump(myInfo);
</cfscript>
Output
EXAMPLE 2
<cfscript>
// string data
a = "abcd"
// generate the key
key = GenerateSecretKey("AES")
iterations="AssoicatedData"
randomIntegers = [];
// generate the SALT value
for ( i = 1 ; i <= 12 ; i++ ) {
arrayAppend( randomIntegers, randRange( -128, 127, "SHA1PRNG" ) );
}
initializationVector = javaCast( "byte[]", randomIntegers )
// encrypt srring
enc1 = Encrypt(string=a,
key=key,
encoding="UU",
algorithm="AES/GCM/NoPadding",
IV_Salt=initializationVector,
iterations=iterations)
// decrypt string
dec1= Decrypt(string=enc1,
key=key,
encoding="UU",
algorithm="AES/GCM/NoPadding",
IV_Salt=initializationVector,
iterations=iterations)
writeDump(dec1)
</cfscript>
Output
abcd