How can I verify the hash of the plain text without being able to decrypt the cipher text?

I am building an E2EE chat app where there is one asymmetric key pair per group and one asymmetric key pair per user. All messages in a group chat are encrypted with the group public key and decrypted with the group private key.
When Alice… Continue reading How can I verify the hash of the plain text without being able to decrypt the cipher text?

What are possible implications of ignoring the ssh host key warning?

With password authentication you’re basically giving your password to the attacker. At least that is my understanding. What about public key authentication? I hear that a private key never leaves your side, and that it’s not possible to pe… Continue reading What are possible implications of ignoring the ssh host key warning?

How can I prove the content of a PGP-encrypted message to a third party?

Imagine this scenario

A StackExchange user sends you a PGP-encrypted message
You decrypt the message and discover that you are being blackmailed
You report the message to the admins but they are unable to view the content

In this situati… Continue reading How can I prove the content of a PGP-encrypted message to a third party?

Can double public key authentication be used as 2fa in privacy based use cases?

MFA with the characteristics of "Something we have" commonly consists of FIDO, OTP and TOTP.
In my use case(privacy focused), FIDO, OTP and TOTP can’t be used due to the fact that they require the binding of private/personal iden… Continue reading Can double public key authentication be used as 2fa in privacy based use cases?