Key Restrictions:

To ensure the safety of our system, we operate a 'constant turnover' policy. This means that no private key is deemed permanent. We set a limit to the lifetime of any key to six months, and will advise on any decisions that any customer wishes to take concerning these limits.

Keys will be set limits for the transactions that they can perform during one week - this can be negotiated with our advisory team as to the needs of any particular key having a high transaction limit and an extended lifetime.

Each transaction will be preset to a particular level, above which the value must never rise, and indeed the software will not allow this to come to pass. These settings can also be adjusted to suit individual needs.

Finally, the total value of transactions authorised with a key is limited - each key will therefore last the shortest time between six months and the time taken to reach this threshold.

Multiuser systems:

A multiuser cheque-sending method differs from the single user as follows:

User logging-in using their given name and password :-

This stage is important for large companies since users (company members/staff) can be given access solely to those elements of the program that are essential for their work.

The program can store a database of possible recipients managed by the system administrator (company chief etc.) A user may only have been access to a limited portion of the recipient database, and thus can only send cheques to parties to which the system administrator has given them rights.

Manual public/private key entries are prohibited, only the recipients name is enetered. Besides which manual entry of a key in standard ASCII would require a lot of time, since they are 128 bits long for high security systems.

In the interests of security that does not compromise efficiency since it requires a lot of time to employ, the TSEB system does not make use of a personalised form of electronic paying-in book. In fact, this approach enables us to limit our costs effectively, as well as providing us with a speed edge over many of our competitors. Using personal paying in slips would necessitate the storage of an image of the slip, taking up valuable space and providing an additional security risk.

Logging:

All transactions are logged at source and destination. A search algorithm at the bank's end as well as at the multi-user's end will continually be in use monitoring all logs. It highlights instances that are anomalous, for example, strange abnormal sums of money, unusual destinations, times of sending etc. The depth of these records can be individually set to requirements for each account as necessary to take into account the varying securites of accounts and the money held within them.

Logs are tamperproof and kept encrypted, and so can be produced as evidence in a court of law, since each record has a corresponding encrypted digital signature.

Bank Security:

The safety of this system is that if the bank's private key is (if however unlikely) compromised then an interloper would be able to find out details of any cheque, although he would not be able to send an altered version to the bank unless he had access to both person A and person B's private keys. This is unlikely. However our bank's public keys are changed on a strictly regular basis.

Clearing:

The case of clearing cheques between two different banks does not involve implementing any new systems for clearing cheques, and simply relies on the existing methods employed by banks at the moment.