Crescendo Cloud Driver

Crescendo Cloud driver for Crestron control systems

Getting Started

Due to quirks with SIMPL+, the driver is divided into 2-Series and 3-Series folders. The Crescendo Cloud.usp files are identical in both folders, but the Crescendo Cloud.ush header files are scoped to each processor type.

To keep the module inputs, outputs, and parameters neatly aligned, the driver is not wrapped in a user macro, which would force all the parameters to the bottom of the module. However, there a few SIMPL symbols the driver depends on that need to be added to the program along with the driver.

1. Clone or download this repository.
2. Choose the 2-Series/ or 3-Series/ processor.
3. Copy Crescendo Cloud.usp to your program directory, which will make it available as a project module.
4. Open Crescendo Cloud.smw in SIMPL Windows.
5. Copy the Crescendo Cloud folder from the Crescendo Cloud program.
6. Paste the folder into your program.

This will provide a completely linked module, neatly aligned and ready for custom integration.

2-Series

Performance

The Crescendo Cloud driver is a high-performance standalone SIMPL+ module. With default settings, it supports 198 digital, analog, and serial key:value pairs. These can be reduced for a (very slight) performance increase or expanded if more values are needed:

// Input/Output Sizes
#DEFINE_CONSTANT #KEY_VALUE_SIZE   198
#DEFINE_CONSTANT #KEY_VALUE_SIZEx2 396

Values are keyed for transmission using a simple array index and transmission performance is not affected by the number of key:value pairs.

Digital_Value_Is[197] = 1; // index is 197, key is Digital_Key[197]

Values are looked up on receipt using a hash table of keys. This hash table is extremely performant (over 2,100 ops/sec on 3-Series and 1,600 ops/sec on 2-Series). More importantly, hash table performance does not degrade if the size of the hash table increases.

Security

For performance reasons, the driver does not use encryption or checksums. Enterprise-grade encryption between the client network and Crescendo Cloud is available via IPSec, which should be configured on the client network equipment. Checksums are delegated to TCP, which includes a robust 16-bit checksum on every segment.

Password

A future version of the driver may include an optional password. Further discussion is available on Issue #1.

ID as Password

The processor model, serial number, and MAC address are concatenated to form a processor ID, which functions as a password.

Our processor sample set has a range of over 30 processor models (2⁵), 10 million serial numbers (2²²), and 4 million MAC addresses (2²¹). Entropy is reduced by a correlation between the uppermost four bits of the MAC address with a serial number (-2⁴). A naive adversary wishing to exploit a random processor out of n total processors would have to to search 2⁵ × 2²² × 2²¹ ÷ 2⁴ ÷ n ÷ 2 = 2^{5 + 22 + 21 - 4 - log₂n - 1} = 2^{43 - log₂n} locations on average for a single exploit.

NOTE: 2-Series processors do not have serial numbers accessible from the Crestron operating system, see Issue #2.

A well-informed adversary could exploit a specific processor easily, but it is not clear that Crescendo Cloud creates additional security risk against such an adversary, especially an adversary with physical access to the processor.