The claim is that as a result of the Great Firewall’s recent attempt to modernize in light of new Internet protocols, the Firewall faces “unprecedented vulnerabilities” (“QUIC Protocol Flaws Expose Censorship Vulnerabilities,” Zoombangla, August 6, 2025).
The Great Firewall’s attempt to bock QUIC-encrypted traffic “has inadvertently created new weaknesses—making censorship less effective while exposing China’s networks to potential disruption.”
QUIC to the rescue
Networks Training describes QUIC—Quick UDP Internet Connections—as “a new generation Internet protocol that speeds online web applications that are susceptible to delay, such as searching, video streaming etc., by reducing the round-trip time needed to connect to a server.”
UDP, user datagram protocol, is in turn “a communication protocol used across the internet for time-sensitive transmissions such as video playback or DNS lookups. Unlike transmission control protocol (TCP), UDP is connectionless and does not guarantee delivery, order, or error checking, making it a lightweight and efficient option for certain types of data transmission.”
So UDP is fast and sloppy and QUIC is faster and maybe not sloppier, because according to Network Training, “By replacing TCP with UDP and encrypting most of its payload, QUIC reduces the time it takes to start viewing the content two to three times, while maintaining data security.”
What is the problem for the Great Firewall? Well, according to Zoombangla, the firewall “implemented critical shortcuts” when it “rolled out QUIC-specific censorship in April 2024.” The “critical shortcuts” of this ambitious upgrade created gaps in the censorship.
“During peak traffic hours, Stanford researchers observed delayed blocking and missed connections as the system struggled with cryptographic operations. As one researcher noted: ‘The firewall must handle millions of connections using keys derived from each packet’s connection ID. When overwhelmed, it fails silently.’…
Shaky foundations
“The Great Firewall still stands, but its foundations are shaking. As censorship systems grow more complex to control modern protocols like QUIC, they become slower, more fragile, and paradoxically easier to circumvent. This research proves that even the most fortified digital barriers develop cracks when stretched beyond their limits—and that open-source ingenuity can turn design flaws into pathways for free information flow.”
I hope that this is true and that the technicians who work for the Chinese Communist Party don’t figure out a way to plug the gaps.
Meantime, the anticensorship strategy seems to be: find ways to overwhelm the system.
