GitHub has introduced new authentication token formats designed to enhance security and improve the detection of compromised tokens. The updated tokens feature identifiable three-letter prefixes and a separator to distinguish them clearly, reducing false positives in secret scanning to 0.5%. A checksum has been added to virtually eliminate false positives, using a CRC32 algorithm encoded with Base62. The new token formats also maintain or increase token entropy, ensuring a high level of uniqueness without altering token length. GitHub encourages users to reset personal access and OAuth tokens to benefit from these security improvements. Additionally, service providers issuing tokens are advised to adopt these practices and participate in GitHub's secret scanning program to enhance their security measures.