Connection without encryption

[AndrzejB]

Documentation specifies levels of security mode 1, and first level means that connection is without any encryption. But how it is possible? Every connection starts with pairing, and even if devices were bonded without exchange LTK or CSRK, the pairing will be required at start of subsequent connection.

And second question, how to dermine the level of security of connection in LE Credit Based Flow Control Mode?

Thank you in advance for help :)

[RK]

No. Every connection does not start with encryption, every connection starts with a simple connection and unless a procedure is started to initiate encryption, it stays unencrypted.