Tor has upgraded its encryption method to enhance security and user anonymity by replacing the outdated tor1 relay encryption algorithm with a new one called Counter Galois Onion (CGO). This shift aims to bolster the network's defenses against contemporary traffic interception attacks that threaten data integrity and user privacy. The Tor network, which relies on a series of relays to route data through three nodes—entry, middle, and exit—adds layers of encryption using onion routing, making it a go-to tool for activists, journalists, and privacy advocates, as well as some cybercriminals. The tor1 algorithm had significant vulnerabilities, including the use of AES-CTR encryption without hop-by-hop authentication, which allowed adversaries to modify traffic and perform tagging attacks. It also suffered from partial forward secrecy, reusing AES keys throughout a circuit's lifetime, and relied on a 4-byte SHA-1 digest for cell authentication, which posed a risk of forgery. In contrast, CGO employs a Rugged Pseudorandom Permutation (RPRP) design, offering protection against tagging attacks through wide-block encryption and tag chaining. It also updates keys after each cell for better forward secrecy and replaces SHA-1 with a 16-byte authenticator, enhancing overall authentication strength. The transition to CGO is currently underway for both the C Tor implementation and its Rust-based client, Arti. Users of the Tor Browser will automatically benefit from this upgrade once it is fully deployed, although no specific timeline has been provided for when CGO will become the default option. The introduction of CGO addresses many of the flaws in the previous system without significantly increasing bandwidth usage, ensuring that user privacy remains a top priority.