Week 3 Bench: Tracing by hand

Reading a captured power trace against the code that produced it, one operation at a time

8 March 2027

Before the Bench#

Read the week’s deck before arriving — it walks through one trace slowly, which this session assumes you have already seen once.

In the Bench#

Working from a supplied oscilloscope capture and the short program that produced it, mark the trace up by hand: where the modular exponentiation’s loop starts, how the trace shape changes on a squaring step versus a squaring-and-multiply step, and where that shape stops being ambiguous to the eye. The point is not to break anything — the program is a toy already known to leak — it is to build the habit of reading current draw as a sequence of operations rather than as noise.

Afterwards#

Keep your annotated trace. The Trace Analysis Lab supplies a new, unannotated one from a different program and asks you to do this again without a lecture walking you through it first.