CTF Writeup: PowerAnalysis: Warmup

Challenge OverviewThe challenge provides a remote service that performs encryption. The description hints that the algorithm leaks a "bit" of data during computation. Unlike traditional crypto challenges where you attack the math, here we attack the implementation by observing side-channel leakage.2. The Vulnerability: Side-Channel LeakageThe core of the problem is a Power Analysis vulnerability. In a real-world scenario, a CPU uses slightly more power to process a 1 than a 0, or takes more time if a specific branch of code is executed.In this challenge, we assume the leakage allows us to determine if our guess for a specific bit of the key is correct.3. Exploitation StrategyThe attack is performed bit-by-bit. Instead of brute-forcing $2^{128}$ possibilities (which is impossible), we only need to test each bit position.Connect to the challenge via a Python socket.Iterate through each bit of the key (from 0 to 127).Submit a guess for the current bit.Analyze the leakage: If the response