AES 128 remains secure against quantum threats

Contrary to popular belief, AES 128 encryption is considered secure even in a post-quantum computing era, according to cryptography engineer Filippo Valsorda. He clarifies that quantum algorithms like Grover's do not simply halve the effective security of symmetric keys, as commonly misunderstood. The parallelization capabilities of classical computers are fundamentally different from the serial nature of Grover's algorithm, meaning quantum attacks do not scale as efficiently as feared. Valsorda argues that this misconception diverts attention from genuinely necessary post-quantum transition work, emphasizing that the actual computational cost for quantum computers to break AES 128 remains prohibitively high.