如何在不泄露密码的情况下整合两个异构网站实现跨站登录与账号创建？

Absolutely, this is totally achievable—you’ve got two clear integration goals, and both can be implemented securely while preserving your existing password security practices. Let’s break down how to tackle each requirement:

1. 已登录Site Two的用户通过Web API在Site One创建账号 #

This relies on establishing a trusted client relationship between Site Two and Site One, since we want to ensure only legitimate, authenticated users from Site Two can create accounts on Site One:

• Step 1: Secure API Authentication
  First, set up a way for Site Two to prove its identity to Site One’s API. Options include:

  • Using a secret API key (stored securely on both sides) that Site Two includes in request headers like Authorization: ApiKey <your-secret-key>.
  • Implementing OAuth2 Client Credentials flow, where Site Two gets a short-lived access token from Site One’s auth server before making API calls (sent via Authorization: Bearer <access-token>).
    Critical: All API traffic must use HTTPS to prevent credential interception.

• Step 2: User Data Transfer & Account Creation
  When a logged-in Site Two user triggers the account creation:

  • Site Two sends the necessary user data (e.g., username, email—avoid sending plaintext passwords unless absolutely necessary) to Site One’s dedicated account creation API, along with its authentication credential.
  • Site One validates the credential first. Once confirmed, it generates a secure random password (or if you want users to set their own later, store a temporary hash and send a password reset link to the user’s email), adds a unique salt, hashes the password using your existing method, and saves the account to your SQL database.
  • Return a success/error response to Site Two, which can then notify the user their Site One account is ready.

2. 从Site Two一键无缝登录Site One (单点登录/SSO) #

For seamless login, you’ll want a way to let Site One trust the authentication status from Site Two. The most reliable cross-domain approaches are:

Option A: JWT-Based SSO (Simple & Direct) #

• When the user clicks "Login to Site One" on Site Two, Site Two generates a short-lived JWT containing the user’s unique identifier (e.g., their Site Two user ID or email, which should match the one used to create their Site One account). Sign this JWT with a shared secret key only known to both sites.
• Redirect the user to Site One’s SSO callback endpoint, passing the JWT as a query parameter (or in a secure cookie, if possible).
• Site One verifies the JWT’s signature and expiration time. If valid, it looks up the corresponding user account in its database, creates a user session (using your existing session management), and redirects the user to their Site One dashboard.

Option B: OAuth2/OpenID Connect (Standardized & Scalable) #

If you want a more robust, industry-standard solution (great for long-term maintainability across separate companies):

• Treat Site Two as an Identity Provider (IdP) and Site One as a Relying Party (RP).
• When the user initiates the seamless login, Site One redirects them to Site Two’s authorization endpoint (though since the user is already logged in, this will skip the login prompt).
• Site Two returns an authorization code to Site One, which exchanges it for an access token and user info.
• Site One uses the user info to find the existing account, creates a session, and completes the login.

Key Security Best Practices #

• Never transmit plaintext passwords between sites—always use hashed values or temporary tokens.
• Set short expiration times for JWTs and access tokens to limit the impact of potential leaks.
• Enable HttpOnly, Secure, and SameSite=Strict flags on cookies used for sessions or token storage.
• Regularly rotate shared secrets/API keys used for authentication between the two sites.
• Keep your password hashing logic (salt + hash) intact for all Site One accounts, whether created via API or user sign-up.

内容的提问来源于stack exchange，提问作者LarryBud