[pgalvin]

> However, they just change their original message, maybe to remove a typo, change the date or add a friendly note. Then the three letter agency does a glorified 'diff' and they are subsequently in on the chat.

Could you expand on this please?

[raisin_churn]

They cannot because PGP has no such vulnerability.

[Theodores]

You must be joking!

[Dx5IQ]

It is hard to imagine that "modern" encryption would be susceptible to known plaintext attacks, please provide some citations.