Is there such a cryptography where I can prove that someone decrypted an encrypted string? Say I wanted to attach a Bitcoin private key in some type of digital container, but in order to open this digital container, I would need to break a digital seal.
I'm basically trying to find a digital equivalent of how a security wax seal works to make a letter tamperproof:
What is the digital equivalent of this? I can write down a bitcoin private key in the envelope and have a wax seal on it. But how do I do this via email?