NetTeller System Security

Commercial Bank and Trust Company understands the security of your personal and account information is important to you. To assist us in offering Internet banking services in a secure manner, we use several different types of technology to ensure the confidentiality of your accounts.

Access Codes

An important security measure rests with you. Your transactions are protected by your individual NetTeller ID and NetTeller PIN, assigned initially by Commercial Bank. You will be required to change your PIN upon your initial log on. You should carefully select a password (PIN) that is hard to guess. It is your sole responsibility to control and protect your ID and PIN.

Time Out Feature

To further protect you, a time out feature is used. We will end your NetTeller session if we have detected no activity for 10 minutes. This is to protect you in case you accidentally leave your computer unattended after you logged on. We recommend that you always sign off (log out) when you are done with your online banking.


Commercial Bank uses a protection measure known as a firewall to protect our computer systems and your information. Firewalls can be thought of as selective barriers that only let authorized traffic (i.e. you, our NetTeller banking customer) through.


The privacy of the communications between you (your browser) and our servers is ensured using encryption. Encryption scrambles messages exchanged between your browser and our online banking server. Encryption happens as follows: When you go to the sign-on page for online banking, your browser establishes a secure session with our server. The secure session is established using a protocol called Secure Sockets Layer (SSL) Encryption. This protocol requires the exchange of what are called public and private keys. Keys are random numbers chosen for that session and are only known between your browser and our server. After the keys are exchanged, your browser will use the numbers to scramble (encrypt) the messages sent between your browser and our server. Both sides require the keys because they need to de-scramble (decrypt) the messages when they are received. The SSL protocol not only ensures privacy, but also ensures that no other browser can “impersonate” your browser, nor alter any of the information sent.

Network Security

The network architecture used to provide the online banking service was designed by the brightest minds in network technology. While the architecture is too complex to explain here, it is important to point out that the banks computers that store your actual account information are not hooked up to the Internet. The requests you make through the Internet are handled by our home banking servers, which retrieve the information you requested from our mainframe via proxy-based firewall servers. These servers act as the go-between you and our mainframe computers.

Additional Measures

New advances in security technology are happening daily, and Commercial Bank is constantly evaluating its security architecture to ensure that it provides the highest level of privacy and safety for bank customers.

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