Multi-Factor Authentication for APIs

Multi-Factor Authentication for APIs

Multi-factor authentication (MFA) significantly enhances API security by requiring multiple verification methods. While traditionally associated with user interfaces, MFA concepts apply to API authentication through various implementation patterns. Time-based One-Time Passwords (TOTP), SMS codes, or push notifications provide additional authentication factors.

# Python example of TOTP-based MFA for APIs
import pyotp
import time

# Setup phase - generate secret for client
secret = pyotp.random_base32()
totp = pyotp.TOTP(secret)

# Authentication phase
def authenticate_with_mfa(username, password, totp_code):
    # First, verify username and password
    if not verify_credentials(username, password):
        return False
    
    # Then verify TOTP code
    totp = pyotp.TOTP(get_user_secret(username))
    if totp.verify(totp_code, valid_window=1):
        # Generate and return access token
        return generate_access_token(username)
    
    return False

# Client usage
current_totp = totp.now()
token = authenticate_with_mfa("[email protected]", "password123", current_totp)

Risk-based authentication adds intelligence to MFA decisions. APIs can require additional authentication factors based on request characteristics like IP address, device fingerprint, or unusual behavior patterns. This adaptive approach balances security with user experience, applying stronger authentication only when risk indicators warrant it.