Ironically, I wonder if something like lettermail is now more secure.
We do know that the exterior of every single piece of mail handled by the USPS is photographed, documented, and retrievable later[1]; but the content of the envelope seems like it may have some level of protection, if only because of the absurdly costly effort of opening and re-sealing in a way that doesn't reveal tampering.
Throw in some level of cryptography, use cursive (so it's harder to OCR), and use code words, and you probably have something better than e-mail.
We do know that the exterior of every single piece of mail handled by the USPS is photographed, documented, and retrievable later[1]; but the content of the envelope seems like it may have some level of protection, if only because of the absurdly costly effort of opening and re-sealing in a way that doesn't reveal tampering.
Throw in some level of cryptography, use cursive (so it's harder to OCR), and use code words, and you probably have something better than e-mail.
[1] https://en.wikipedia.org/wiki/Mail_Isolation_Control_and_Tra...