Thanks for the kind words! SD cards should be safe. NFC depends on the stack/security of each part. Bluetooth also depends on stack/security of each part. QR relies on the QR parsers and all the bcur dependencies, as well as PSBT parsing dependencies.

blockstream_official

bitcoin

AMA - Blockstream Jade Team Enables Air-Gapped Transactions

Hi Blockstream Jade team!  

I just wondered, how does the security of air-gap transaction by QR code compare to the other forms of air-gapped transactions?  For example, the Coldcard using a microSD, or Ledger Nano X or Jade using Bluetooth, or using NFC methods (does that count as air-gapped)?  

I guess there are pros and cons to each method, but how would you say QR stands up overall, compared to the other ways?

Love your work at Blockstream, by the way!  :-)