Website Coding & Design 825 views Aug 18, 2015
Security Architecture for Universal Mobile Payment system

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One of the important limitations for mobile payments is the security associated with the payment solutions. I propose two attributes that can be exploited  for security architecture:



  • access control
  • isolation


Access control

Access control is the most widely exploited attribute in current security systems. in this approach, access to information that is required to be secure is controlled either by restricting its access. this can be done by two different levels. at the first level, the information is accessed through password control. while this might be acceptable for medium security requirements, the main problem for high security requirements is that the security system is rendered ineffective when the password is compromised (i.e. single point of failure).


at the second level, the information itself can be encrypted so that only those with the decryption key can access the content of  information.  this method if used in addition to the password provides an extra security layer, which keeps the system secure even when the password is compromised. this solution however is usually computationally expensive, but as the performance and cost of computational machines keep improving this may become more and more acceptable.



In access control, the architecture does not target control of information flow or storage within the system. as a result information follow and storage may be liberally distributed all over  system despite its security status. In isolation approach, the information flow and storage is confined with architected security  zones of the system.  a security zone determined by the agents that transact and the necessary information needed for the to transact.

As an example let us look at a mobile payment system. the typically agent based architecture is shown below:


The mobile payment system defines six security zones: 


zone AB

Zone AB is between the mobile user and the mobile phone. usually the security features required here is password control to services. This security feature should never flow or be stored outside the security zone. it is thus isolated to this zone only.


If a mobile phone is stolen the thief will need password to access services on the mobile phone. Some form of password control  is currently readily implemented on existing mobile phones.


zone BC

Zone BC is between the mobile phone and the payment services provider.  The mobile phone purchases payment certificates from the payment services provider. These payment certificates can be used later to pay for goods and services from the goods and services provider. The payment certificates can be viewed as a kind of bankers check. It is a promise by the payment services provider to pay when the certificate is presented to them. The security issue here is clearly authentication.  In such a case, one possible payment service solution is for the payment services provider to provide authentication services (software) for their certificates for the goods and services  provider.  Here we can have online and offline authentication services. The online authentication services connect to the payment service provider for authentication.  The offline authentication services use resident service(software) provided by the payment provider.


The authentication service is made more secure by that fact that; first, to the goods and services provider it is a black box. Second, the payment services provider has flexibility in design and selection of security features, such as encryption, special codes for certificates, and even security questions to the client. In cases of managed risk exposures, the certificates can be used offline, i.e. even when the line is down.  Information, like the source of funds, e.g. bank account should be prevented from flowing or being stored outside this security zone. Only certificates may be visible outside the security zone.


zone BD

Zone BD is between the mobile phone and the goods and services provider.  The mobile phone uses certificates to pay for goods and services. The services provider uses the authentication services of the payment services provider to validate the certificates. The ability to have offline authentication means that payment services can be conducted offline albeit in risk managed cases. the security requirements for this zone should include?


zone CD

Zone CD is between the payment service provider and the goods and services provider. With offline payment services the goods and services provider runs a resident service (software) from the payment services provider. For online authentication, the goods and services provider connects to the payment services provider. Security features could include variations of password control and authentication.   And every effort should be made to confine this information to this security zone. This may imply source routing of messages.


Face to face zone

Finally zone AC and AD can be called the face to face security zone. These zones involver the client and either the goods and services provider or the payment services provider.  In this case the user is on hand to carry out and validate any transaction. This could be the only mode when risks are unacceptable. For example this may be the only available way to transact when abnormally large sums of money are involved.

Tags: #security 

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