{
  "topic": "http-handshake",
  "type": "fill_blank",
  "schema_version": "1.0.0",
  "generated": "2026-09-02T21:20:00+08:00",
  "questions": [
    {
      "id": "fb-001",
      "type": "fill_blank",
      "difficulty": 2,
      "tags": [
        "TCP",
        "三次握手"
      ],
      "question": "TCP 三次握手中，第二次握手服务器发送的标志位是____。",
      "answer": [
        "SYN-ACK"
      ],
      "explanation": "第二次握手服务器发送 SYN-ACK（Synchronize-Acknowledge），表示收到客户端的连接请求并确认，同时自己也准备好建立连接。",
      "source": null,
      "related": []
    },
    {
      "id": "fb-002",
      "type": "fill_blank",
      "difficulty": 3,
      "tags": [
        "TLS",
        "HTTPS"
      ],
      "question": "TLS 1.3 相比 TLS 1.2 将握手耗时从 2-RTT 优化到了____-RTT。",
      "answer": [
        "1"
      ],
      "explanation": "TLS 1.3 优化了握手流程，将握手耗时从 TLS 1.2 的 2-RTT 优化到 1-RTT。TLS 1.3 的 0-RTT 恢复可以在恢复会话时做到 0-RTT。",
      "source": null,
      "related": []
    },
    {
      "id": "fb-003",
      "type": "fill_blank",
      "difficulty": 2,
      "tags": [
        "HTTP/1.x"
      ],
      "question": "HTTP/1.0 和 HTTP/1.1 在应用层____（有/没有）握手。",
      "answer": [
        "没有"
      ],
      "explanation": "HTTP/1.0 和 HTTP/1.1 没有应用层握手。TCP 连接建立后，TLS 握手完成后，客户端直接发送 HTTP 请求。",
      "source": null,
      "related": []
    },
    {
      "id": "fb-004",
      "type": "fill_blank",
      "difficulty": 3,
      "tags": [
        "HTTP/2",
        "SETTINGS"
      ],
      "question": "HTTP/2 在连接建立后通过____帧交换连接参数。",
      "answer": [
        "SETTINGS"
      ],
      "explanation": "HTTP/2 在连接建立后通过 SETTINGS 帧交换参数，如最大并发流数、窗口大小等。这不算严格的「握手」，但起到类似的协商作用。",
      "source": null,
      "related": []
    },
    {
      "id": "fb-005",
      "type": "fill_blank",
      "difficulty": 4,
      "tags": [
        "HTTP/3",
        "QUIC"
      ],
      "question": "HTTP/3 基于 QUIC 协议，QUIC 将传输层握手和____握手合二为一。",
      "answer": [
        "TLS 1.3"
      ],
      "explanation": "QUIC 把传输层握手和 TLS 1.3 握手合二为一，首次连接只需 1-RTT，恢复连接可达 0-RTT。",
      "source": null,
      "related": []
    },
    {
      "id": "fb-006",
      "type": "fill_blank",
      "difficulty": 2,
      "tags": [
        "TCP",
        "三次握手"
      ],
      "question": "TCP 三次握手的本质是双方各确认一次____能力。",
      "answer": [
        "收发"
      ],
      "explanation": "三次握手的本质是双方各确认一次收发能力，确保连接可靠。客户端确认自己能发能收，服务器确认自己能发能收。",
      "source": null,
      "related": []
    },
    {
      "id": "fb-007",
      "type": "fill_blank",
      "difficulty": 3,
      "tags": [
        "TLS",
        "HTTPS"
      ],
      "question": "TLS 握手完成的三件事包括证书验证、密钥协商和____确定。",
      "answer": [
        "加密套件"
      ],
      "explanation": "TLS 握手完成的事包括：证书验证（确认服务器身份）、密钥协商（生成对称加密密钥）、加密套件确定（双方商定使用的加密算法）。",
      "source": null,
      "related": []
    },
    {
      "id": "fb-008",
      "type": "fill_blank",
      "difficulty": 4,
      "tags": [
        "HTTP/3",
        "QUIC"
      ],
      "question": "HTTP/3 基于____协议运行在 UDP 之上。",
      "answer": [
        "QUIC"
      ],
      "explanation": "HTTP/3 基于 QUIC 协议，QUIC 运行在 UDP 之上。QUIC 内置了 TLS 1.3、可靠传输、多路复用和 0-RTT 恢复。",
      "source": null,
      "related": []
    },
    {
      "id": "fb-009",
      "type": "fill_blank",
      "difficulty": 3,
      "tags": [
        "TLS",
        "0-RTT"
      ],
      "question": "TLS 1.3 的 0-RTT 恢复虽然快，但存在____攻击风险。",
      "answer": [
        "重放"
      ],
      "explanation": "0-RTT 恢复虽然快，但存在重放攻击风险。0-RTT 发送的数据不能保证幂等性，因此不适合做敏感操作（如支付）。",
      "source": null,
      "related": []
    },
    {
      "id": "fb-010",
      "type": "fill_blank",
      "difficulty": 4,
      "tags": [
        "HTTP/2",
        "TCP"
      ],
      "question": "HTTP/2 的 SETTINGS 交换发生在____层，解决的是「怎么高效通信」的问题。",
      "answer": [
        "应用"
      ],
      "explanation": "HTTP/2 的 SETTINGS 交换发生在应用层，目的是协商 HTTP 协议参数（如最大并发流、窗口大小等）。TCP 握手解决的是「能不能通信」。",
      "source": null,
      "related": []
    }
  ]
}