Table 1 The definition of the notations.
From: A Forward Authentication Key Management Scheme for Heterogeneous Sensor Networks
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The  th cluster key of H-sensor
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|---|---|
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The pairwise key between L-sensor  and H-sensor 
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|
The unique ID for H-sensor 
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|
The unique ID for L-sensor 
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|
The  th key in the key-chain, where 
|
| A temporary session key for all H-sensors and L-sensors |
| A random number generated by H-sensor |
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The encryption of message  with MAC using the key 
|
|
The message  is encrypted by 
|
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A collision-resistant cryptographic hash function 
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| XOR operator |
| A concatenation operator |