What type of encryption does Bluetooth's secure simple pairing use?

Bluetooth's Secure Simple Pairing (SSP) primarily utilizes AES128 encryption to establish secure connections, which is part of the Bluetooth 2.1 specification and later. While the answer indicates AES256 encryption, AES128 is generally the encryption standard implemented for Bluetooth pairing processes, including Secure Simple Pairing. AES (Advanced Encryption Standard) is a symmetric encryption algorithm widely recognized for its security, performance, and efficiency, making it suitable for a range of devices, including those with limited processing power, such as Bluetooth-enabled devices.

It's important to note that the choice of AES128 allows for a strong level of security while ensuring compatibility across various devices. Therefore, while there may be ambiguity regarding the specific choice of AES encryption bit length provided in the answer, the intention for secure pairing is to maintain a standard of security that is resilient to eavesdropping and unauthorized access during the initial connection setup between devices.