[[["易于理解","easyToUnderstand","thumb-up"],["解决了我的问题","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["没有我需要的信息","missingTheInformationINeed","thumb-down"],["太复杂/步骤太多","tooComplicatedTooManySteps","thumb-down"],["内容需要更新","outOfDate","thumb-down"],["翻译问题","translationIssue","thumb-down"],["示例/代码问题","samplesCodeIssue","thumb-down"],["其他","otherDown","thumb-down"]],["最后更新时间 (UTC):2025-07-26。"],[[["Message Authentication Codes (MACs) are used to verify that Fast Pair configuration messages originate from Google Mobile Services (GMSCore) and not other apps."],["MACs are generated using HMAC-SHA256, incorporating session and message nonces to prevent replay attacks."],["Providers initiate a session nonce upon RFCOMM connection and seekers generate a unique message nonce for each message."],["To verify a message, providers compute the MAC using the received data and compare it with the received MAC, using stored account keys for verification."],["If MAC verification fails, the provider sends a NAK message indicating an incorrect authentication code."]]],["Message Authentication Code (MAC) ensures messages originate from GMSCore. The Seeker generates a MAC using HMAC-SHA256, derived from a key (K), nonce, and message data. The nonce combines a per-connection session nonce (Provider-generated) and a per-message nonce (Seeker-generated). The Seeker transmits the message nonce and MAC with each message. The Provider verifies the MAC using the same function and stored keys, acting on the message only if the MAC is correct. If not, a NAK is sent.\n"]]