c# – The best way to decrypt a receipt and validate for a Xamarin kinds iOS autonewing subscription?

I might wish to know for a Xamarin Kinds iOS auto-renew subscription:

• Is it necessary to validate a purchase order?
• How can I decrypt an App Retailer Receipt?
• How can I validate a purchase order with out utilizing a server?

VALIDATION

I’ve had the app retailer reject my app saying I must “validate on my server”, however I’ve additionally learn loads of materials on-line the place individuals say a server isn’t obligatory for an auto-subscription that merely unlocks a function within the app and delivers no exterior content material.

The Microsoft Xamarin documentation nevertheless does not describe this state of affairs and solely considers server aspect validation.

https://study.microsoft.com/en-us/xamarin/ios/platform/in-app-purchasing/transactions-and-verification#Securing_Purchases

DECRYPTION

I perceive the receipt is a PKCS #7 container and have learn Apple’s documentation on this however I am not very educated on crytography and may’t work out how I can apply this to a Xamarin Kinds iOS undertaking.

https://developer.apple.com/documentation/appstorereceipts/validating_receipts_on_the_device#//apple_ref/doc/uid/TP40010573-CH1-SW2

Might somebody assist with a Xamarin Kinds, C#, app-side decrypt and validate instance?