> What is the probability that China is reading these messages in real-time
Real-time might be nice but there's value in reading material at this level with almost any delay.
In 1949 a US counter-intelligence program(me), the Venona project[1] decrypted Soviet cables from 1945 which made it almost certain the First Secretary to the British Embassy in Washington DC [2] was a Soviet asset. That wouldn't have happened if the Soviets hadn't misused their channels of communication.
Real-time might be nice but there's value in reading material at this level with almost any delay.
In 1949 a US counter-intelligence program(me), the Venona project[1] decrypted Soviet cables from 1945 which made it almost certain the First Secretary to the British Embassy in Washington DC [2] was a Soviet asset. That wouldn't have happened if the Soviets hadn't misused their channels of communication.
[1] https://www.osti.gov/opennet/manhattan-project-history/Event... [2] https://en.wikipedia.org/wiki/Kim_Philby