ColdFusion Encrypt with Salt + Iterations, not working - encryption

Question

Here is the function, with variable names in place
encrypt(arguments.input, key, algorithm, encoding, arguments.salt, iterations)
I'm using a 256 bit AES key which is 44 characters long.
I am choosing AES and base64 for Algorithm and Encoding.
I've tried various ways of generating a salt,
createUUID(), generatesecretkey('AES',128) and generatesecretkey('AES',256)
The encrypted result is always the same with the same input, when the salt changes each time. Like it's ignoring it, there is no error to suggest why.
I also note, iterations has no effect on the encryption either.

Answer 1

The algorithm "AES" is actually shorthand for "AES/ECB/PKCS5Padding" (ie algorithm/mode/padding). When using the default ECB mode, the iv will be ignored. Use the longhand algorithm form to specify CBC mode, ie "AES/CBC/PKCS5Padding"
Runnable Example on Trycf.com:
<cfscript>
for (i = 1; i <= 5; i++) {
key = "ji3fd0ZKB87COPz5ZwqsQEQKcuRggtvvO98t3mZFxns=";
// generate different iv's for DEMO only
uuid = CreateUUID();
iv = BinaryDecode( replace(uuid, "-", "", "all"), "hex");
input = "This is plain text to be encrypted";
encoding = "base64";
algorithm = "AES/CBC/PKCS5Padding";
encrypted = encrypt(input, key, algorithm, encoding, iv);
decrypted = decrypt(encrypted, key, algorithm, encoding, iv);
writeOutput("<hr>["& i &"] encrypted="& encrypted );
writeOutput("<br>["& i &"] decrypted="& decrypted );
writeOutput("<br>["& i &"] iv="& uuid );
}
</cfscript>
Note: To use larger keys, like 256bit, you must first have installed the (JCE) Unlimited Strength Jurisdiction Policy Files

Answer 2

AES only supports three key lengths, 16, 24 and 32 bytes. Note that 44 characters is 352-bits which is none of these. But it appears that the encrypt method expects a Base64 encoded string as the key so a 44 character Base64 key would seems to be correct. The documentation does not detail the key form.
Also note that the iv (arguments.salt) must be exactly one block in size, for AES that is 16-bytes.
See Encrypt for more information.
For more help please supply the encrypt arguments and the result.