System and method of installing software applications on electronic devices

A method of controlling a mobile wireless device that comprises a microprocessor and memory, wherein the method comprises:

• receiving a first digital signature key for verifying digital signatures on software applications to be installed on the device;
• determining if any digital signature keys for verifying digital signatures on software applications to be installed on the device exist on the device, and if not, storing the received first digital signature key in the memory;
• receiving a software application for installation on the device;
• verifying a digital signature on the received software application using the first digital signature key;
• and
• installing the software application on the device if the digital signature on the received software application is successfully verified;
• receiving a new digital signature key for verifying digital signatures on software applications to be installed on the device;
• verifying a digital signature on the received new digital signature key using the first digital signature key;
• and
• storing the new digital signature key in the memory to replace the first digital signature key if the digital signature on the received new digital signature key is successfully verified.

A non-transitory computer-readable medium storing instructions executable by a microprocessor which when executed cause the processor to carry out a method comprising:

• receiving a first digital signature key for verifying digital signatures on software applications to be installed on the device;
• determining if any digital signature keys for verifying digital signatures on software applications to be installed on the device exist on the device, and if not, storing the received first digital signature key in the memory;
• receiving a software application for installation on the device;
• verifying a digital signature on the received software application using the first digital signature key;
• and
• installing the software application on the device if the digital signature on the received software application is successfully verified;
• receiving a new digital signature key for verifying digital signatures on software applications to be installed on the device;
• verifying a digital signature on the received new digital signature key using the first digital signature key;
• and
• storing the new digital signature key in the memory to replace the first digital signature key if the digital signature on the received new digital signature key is successfully verified.