Different use cases require trustless event subscription. Among the most fundamental are:

• knowing if a particular extrinsic executed successfully or else get the error message
• knowing what fees have been applied to pay for a particular extrinsic

This has to be possible for each L1-light client separately

The Events require the same security and ordering guarantees that apply to Blocks and extrinsics because we aim to trigger state transitions based on events

• upon each new parentchain block, the untrusted service marshalls the entire event store for that block into the enclave upon providing the block itself to the light client inside the enclave
• the enclave verifies the event store using a storage proof against the block header

This task is done once the verification of the event store succeeds for each parentchain block during a private-tx CI flow