Series intro: Apple Pay Certificate Signing Using .NET At this point, we’ve uploaded our “payment processing” and/or “merchant identity” CSR to Apple (or had our merchant do that on our behalf), Apple has signed our CSR using their CA (Certificate Authority) private key, and we have downloaded the final Apple-issued certificate (.cer extension) to our […]
Series intro: Apple Pay Certificate Signing Using .NET Apple’s guide for configuration has two sections, one for “payment processing certificate” and one for “merchant identity certificate.” Both basically use the same steps: You generate a CSR (Certificate Signing Request) using the Keychain Access application on some Mac, upload it to Apple, and then download a […]
This series is a follow-up to the Decrypting Apple Pay Payment Blob Using .NET series already posted. Before you can decrypt an Apple Pay blob you must register a “payment processing” certificate with Apple. To really test the entire flow, you’ll probably also want a “merchant identity” certificate (used for getting blobs in the first […]
If you are like me, you love coding. There is little else you would rather be doing. But that’s not the only thing we have to do, is it? There’s a lot of ceremony that comes with writing software. Ticketing systems. Documentation. Architectural diagrams. Emails. As we go along, less and less of our time […]
I noticed this pattern in play while working on the System.Text.Json code in .NET Core (corefx) and immediately fell in love with it. Consider this method signature: Lots of complex stuff being passed into this method and much of it is optional. That’s kind of a “code smell” right? This method is a heavy-lifter or […]
Series Intro: Decrypting Apple Pay Payment Blob Using .NET Finally, we’ve arrived at Step 4 on Apple’s guide for decrypting the payment blob, which is the actual decryption. This is where all our efforts will finally bear fruit. What kind of fruit? Apples, of course. Our guides have instructed us as such: For ECC (EC_v1), […]
Series Intro: Decrypting Apple Pay Payment Blob Using .NET Step 3 on Apple’s guide for decrypting the payment blob is where things really start to get interesting. Now we need to derive key material which will be fed into the encryption algorithm we’ll use to decrypt the cipher bytes. Don’t close your laptop! It’s not […]
Series Intro: Decrypting Apple Pay Payment Blob Using .NET Step 2 on Apple’s guide for decrypting the payment blob is probably the easiest. Basically we need to retrieve the “payment processing” certificate that we will use to perform the decryption. Apple’s Configuring Your Environment page covers two types of certificates: “payment processing” & “merchant identity.” […]
Series Intro: Decrypting Apple Pay Payment Blob Using .NET Step 1 on Apple’s guide for decrypting the payment blob is signature verification, which is done basically to make sure the message actually came from Apple and was not tampered with en route to us. That validates the integrity and authenticity of the message which checks […]
If you are here you are likely either a developer working on a payment gateway, or you are a cryptography nut. In either case, welcome! I would be in the former category. Recently at work I found myself tasked with decrypting the Apple Pay blob you get from the Apple Pay on the Web flow, […]