Feature request: AES Key Wrap/Unwrap (RFC 3394)

[KirkLandTrip]

The problem
Some applications use Key Wrapping to store a key (that is used to decrypt some user data) in a "non-trusted" location, usually together with the data it encrypted.
The key isn't stored in plain-text and instead it is stored in an encrypted form, called the "wrapped" form.
This is done by encrypting using a secondary key, called a KEK. This secondary key is usually not stored in the same place.
A common way to implement it is to generate the KEK in memory based on a password/PIN code that a user enters, then decrypt the wrapped key and then use the results to decrypt the user's data.

"AES Key Wrapping" defined in RFC 3394 is a popular way to wrap keys.
It uses the raw AES function but does some arithmetic/shifting around the input/output.
So this is NOT the same as just Running AES-ECB with the input=key_to_wrap and the encryption key=KEK.

The solution I'd like to have
New modules in Cyberchef that work like this:

1. AES Key Wrapping: Works on the input data as the "Key Data" (Key to wrap)
   With 2 parameters:
   * KEK - The Key to encrypt with
   * IV - As defined in RFC 3394, It's prepended to the "Key Data" before encrypting/wrapping it. (It is NOT used as the IV to the AES method. The abused the name "IV" here)
2. AES Key Unwrapping: Works on the input data as the "Wrapped Key"
   With 2 parameters:
   * KEK - The Key to decrypt with
   * IV - As defined in RFC 3394, The first 8 bytes of the decrypted blob should equal to this IV (this is used to verify that unwrapping succeeded).

For both IV parameters, RFC 3394 suggests these 8 bytes:
a6a6a6a6a6a6a6a6
So using it as the default value will probably cover most use cases.

Alternatives I've considered
I've tried using "AES Decrypt"/"AES Encrypt" modules directly before I realized that the usage of AES in the wrapping/unwrapping is not just a simple call to AES, there are several additional shifting and XORing involved.

** Links: **
RFC 3394 - https://www.rfc-editor.org/rfc/rfc3394
Key Wrap in Wikipedia - https://en.wikipedia.org/wiki/Key_wrap

[mikecat]

Implemented! I hope you like this.