I have an open source offline airgapped encrypted device for signing transactions.
Seeds are stored on this device.
Signed transactions are passed to an online machine as a parade of qr-codes for broadcasting to the Tangle.
The online device holds the index, security level, and addresses, but not the seed.
This helps me:
1. Keep track of what addresses have already been used.
2. Look up balances.
3. Send out addresses in order to receive payments.
The online device is not secure because it connects to other devices and to the Internet. If an adversary gains access to this device, can the list of indexes, security levels and addresses be used to crack the seed? Common sense makes me think not but the question is worth asking because many people may wish to manage their funds this way.
Thanks for the clarification.