Ed25519 and RSA are two different cryptographic algorithms used for generating key pairs for secure communication, such as SSH connections.
Offers faster key generation, signing, and verification speeds, smaller key sizes, and is generally considered more secure than RSA for SSH keys.
Widely used and supported, is slower and requires larger key sizes for comparable security.
Key Differences:
Performance: Ed25519 is generally faster than RSA in key generation, signing, and verification operations, potentially leading to quicker logins and improved user experience.
Key Size: Ed25519 keys are significantly smaller than RSA keys, with a public key of only 68 characters compared to RSA's 3072 characters, making them more efficient for storage and transmission.
Security: Both algorithms are considered secure, but Ed25519 is often favored for its strong security and resistance to certain types of attacks. RSA's security relies on the difficulty of factoring large numbers, while Ed25519 relies on the difficulty of solving the discrete logarithm problem on elliptic curves.
Compatibility: RSA is more widely supported across different systems and software, especially older ones. Ed25519 support is increasing, but it may not be available on all systems, especially older ones.
When to choose which:
**Ed25519:**If performance and key size are critical considerations, and the system supports Ed25519, it's generally the preferred choice for SSH keys.
**RSA:**If compatibility with older systems is essential, or if there are specific reasons to prefer RSA, it can still be used, especially with larger key sizes like 4096 bits for enhanced security.