This article explains why the MySQL 8.0 client may report the caching_sha2_password authentication error requiring a secure connection, describes the plugin’s design, RSA and SSL mechanisms, cache behavior, and provides practical commands and replication settings to resolve the issue.
MySQL 8.0 replaces the default mysql_native_password with the caching_sha2_password plugin, which stores a 70‑byte salted SHA‑256 hash with configurable rounds, caches SHA256(password) for fast logins, and falls back to RSA‑encrypted full verification on insecure connections, supporting user creation, replication and key management.
This article explains why Java applications occasionally encounter the "Public Key Retrieval is not allowed" error when connecting to MySQL 8.0, analyzes the role of caching_sha2_password and user authentication cache, and provides practical solutions such as specifying the RSA public key, enabling AllowPublicKeyRetrieval=True, or switching to mysql_native_password.
The article explains how MySQL 8.0's caching_sha2_password authentication plugin works, its caching mechanism, advantages, limitations, and how to generate, view, and use RSA key pairs for secure password exchange in encrypted or RSA‑based non‑encrypted connections.
