In *BLUETOOTH SPECIFICATION Version 4.2 [Vol 3, Part C]*, page 372, there is a section called *LE Security Modes*, which states:

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> There are two LE security modes, LE security mode 1 and LE security mode 2.
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> LE security mode 1 has the following security levels:
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> 1. No security (No authentication and no encryption)
> 2. Unauthenticated pairing with encryption
> 3. Authenticated pairing with encryption
> 4. Authenticated LE Secure Connections pairing with encryption
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> LE security mode 2 has two security levels:
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> 1. Unauthenticated pairing with data signing
> 2. Authenticated pairing with data signing
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I do not really understand the difference between the LE security mode 1 and level 3 and 4. Can somebody say something about this?