TLDR · SCIENCE & FUTURISTIC TECHNOLOGY
QUANTUM COMPUTERS ARE NOT A THREAT TO 128-BIT SYMMETRIC KEYS
Summary from the TLDR newsletter
Both AES-128 and SHA-256 are safe against quantum computers. No symmetric key sizes have to change as part of the post-quantum transition. Almost all experts agree on this. The misconception is usually based on a misunderstanding of the applicability of a quantum algorithm called Grover's.