Modern Cryptography and the Future

Cryptography continues to evolve in response to new threats, new computing paradigms, and new use cases. This lesson explores the cutting-edge developments in cryptographic research and the challenges that lie ahead — including the looming threat of quantum computing.

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The Quantum Computing Threat

Quantum computers use qubits that can exist in superposition (0 and 1 simultaneously), enabling certain computations to be performed exponentially faster than on classical computers.

Impact on Current Cryptography

Algorithm	Quantum Threat	Attack
RSA	Broken	Shor's algorithm factors large numbers efficiently
ECC / ECDSA / ECDH	Broken	Shor's algorithm solves the discrete logarithm problem
Diffie-Hellman	Broken	Shor's algorithm
AES-128	Weakened	Grover's algorithm reduces effective security to 64 bits
AES-256	Secure	Grover's algorithm reduces to 128-bit security — still infeasible
SHA-256	Secure	Grover's provides only a quadratic speedup for pre-image attacks

Key insight: Quantum computing breaks asymmetric cryptography (RSA, ECC, DH) but only weakens symmetric cryptography and hash functions. Doubling the key size (AES-256) provides quantum resilience.

Timeline