What mechanism does Vault use to encrypt data at rest?

Vault uses AES (Advanced Encryption Standard) to encrypt data at rest because it is a widely accepted encryption standard that offers a high level of security and efficiency. AES is symmetric encryption, meaning the same key is used for both encryption and decryption, making it suitable for large amounts of data that Vault needs to handle securely. It operates on fixed block sizes and supports key lengths of 128, 192, and 256 bits, providing flexibility and robustness against various types of cryptographic attacks.

This choice aligns with current best practices in data security, which favor AES due to its strength, performance, and speed, along with being standardized and tested extensively over time. Using strong encryption like AES is critical for maintaining the confidentiality and integrity of sensitive data managed by Vault.

The other encryption methods mentioned are either outdated (like 3DES, which is generally considered less secure and is being phased out) or not as widely used in modern secure data storage solutions. RSA, while popular for key exchange and digital signatures, is not practical for encrypting large datasets due to its slower performance compared to symmetric algorithms like AES. Blowfish, although effective, has been largely eclipsed by the performance and security enhancements found in AES.