Lie detectors are no longer the preserve of shadowy government agencies. Nor are they hard to get.
The KishKish Lie Detector, for example, can be downloaded free as an "extra" on the popular internet phone service Skype. It is capable of monitoring, in real-time, the stress levels in a person's voice.
Its creator, BATM, says higher sound frequencies are a telltale sign that someone is being dishonest.
"What all people have in common is that their stress levels are constantly changing within their current range, changes which indicate the 'perceived jeopardy' or 'danger' of statements being made," reads a product description on the KishKish website.
The lie detector is activated whenever a Skype call is placed, and before giving a reading the software calibrates to the general stress levels of the speaker.
A needle meter moves up and down to illustrate variations from the general stress level, and an indicator light turns from green to red if the software detects a "lie".
To avoid legal troubles, the program automatically informs the other person their conversation is being monitored by a lie detector.
Skype - which has become popular among tech-savvy users because of its competitive landline and mobile call rates - boasts over 100 million users worldwide, and was bought by eBay for $US2.6 billion ($3.2 billion) in September last year.