Peter Shor Broke PKI with Ancient Math, and Futuristic Quantum Computing

This blog post walks through the historical and mathematical foundations of Shor's algorithm—from Euclid's GCD and Babylonian quadratic methods to Fermat/Euler theorems, the Quantum Fourier Transform, and continued fractions—using concrete examples to show how quantum period finding can factor integers and thereby threaten PKI/RSA; it also explains quantum speedup, practical limitations (logical qubits), and the need to transition to post-quantum cryptography (citing developments like Google's "Willow" and national guidance toward PQC by 2030).