Replicating UVB-76

For the uninitiated, UVB-76 is a station that broadcasts coded messages over AM radio. It is still active with messages transmitted as recently as Oct 2016 and is speculated to be related to the Russian military. The transmission and tone generation equipment are from the analog era, hence I was ...

IP Hiding and Cloaking for Services

It is relatively easy to hide the IP address of clients through the use of VPNs and proxies. However, it is a challenge for services since they need to be reachable by the clients. Imagine if your phone number changed at the stroke of midnight everyday, it would be very ...

Measuring Power Consumption

I have recently acquired an electricity usage meter off ebay and decided to measure the power consumption of some of my devices. For a device that costs just 15 SGD, it works wonderfully and can measure voltage, amperage and wattage. It is supposed to be able to calculate electricity cost ...

Saturating 1Gbps bandwidth

My ISP recently gave me a free speed bump from 500Mbps to 1 Gbps. I wanted to test if it was possible to fully utilise the bandwidth on a single file transfer. Firstly, we need to look at the test file size. I settled on a roughly 500MB to 1GB ...

Running HTTPS, SSH and VPN on port 443

A port can only be bound to one service at a time, which makes perfect sense since the OS cannot possibly know which application to route the packet to. However, protocols often have distinct signatures, for example the first few bytes of SSH is always SSH-2.0 while HTTP packets ...

RAID is not backup

A number of friends have recently sought my advice on NAS and RAID solutions for storing their personal data. I do not usually give brand recommendations but I will discuss the technology involved. I have never used RAID nor found a need for it, this is because RAID (Redundant Array ...