A protocol to set up shared secret schemes without the assistance of a mutually trusted par
l2tp mac 密钥
l2tp mac 密钥英文回答：L2TP (Layer 2 Tunneling Protocol) is a widely used VPN (Virtual Private Network) protocol that allows users to establish secure connections over the internet. In order to ensure the security of the L2TP connection, a pre-shared key (PSK) is required. The PSK is a secret key that is shared between the client and the server to authenticate and encrypt the data transmitted over the connection.To set up L2TP on a Mac and configure the PSK, follow these steps:1. Open the "System Preferences" on your Mac.2. Click on "Network" to open the network settings.3. Click on the "+" button at the bottom left to add a new network connection.4. Select "VPN" as the interface and choose "L2TP over IPSec" as the VPN Type.5. Enter a name for the connection in the "Service Name" field.6. In the "Server Address" field, enter the IP address or domain name of the VPN server you want to connect to.7. Click on the "Authentication Settings" button to configure the PSK.8. In the "Shared Secret" field, enter the PSK provided by your VPN service provider.9. Optionally, you can also enter your username and password if required by the VPN server.10. Click on "OK" to save the settings.11. Click on "Apply" to apply the changes.Once the L2TP connection is set up with the correct PSK, you can now connect to the VPN server by selecting the connection from the network menu on your Mac's menu bar.中文回答：L2TP（第二层隧道协议）是一种广泛使用的VPN（虚拟专用网络）协议，允许用户在互联网上建立安全连接。
ipsec原理介绍
Ipsec VPN调研总结一、Ipsec原理Ipsec vpn指采用IPSec协议来实现远程接入的一种VPN技术，IPSec全称为Internet Protocol Security，是由Internet Engineering Task Force (IETF) 定义的安全标准框架，用以提供公用和专用网络的端对端加密和验证服务。
Ipsec是一个协议集，包括AH协议、ESP协议、密钥管理协议（IKE协议）和用于网络验证及加密的一些算法。
1、IPSec支持的两种封装模式传输（transport）模式：只是传输层数据被用来计算AH或ESP头，AH或ESP头以及ESP加密的用户数据被放置在原IP包头后面。
隧道（tunnel）模式：用户的整个IP数据包被用来计算AH或ESP头，AH或ESP头以及ESP加密的用户数据被封装在一个新的IP数据包中。
2、数据包结构◆传输模式：不改变原有的IP包头，通常用于主机与主机之间。
◆隧道模式：增加新的IP头，通常用于私网与私网之间通过公网进行通信。
3、场景应用图4、网关到网关交互图5、Ipsec体系结构：6、ipsec中安全算法●源认证用于对对等体的身份确认,具体方法包含:PSK(pre-share key);PK3(public key infrustructure公钥基础设施)数字证书,RSA等,后两种为非对称加密算法。
●数据加密对传输的数据进行加密,确保数据私密性,具体对称加密算法包含:des(data encrypt standard)共有2种密钥长度40bits,56bits,3des密钥长度为56bits的3倍;aes(advanced encrypted standard)AES 加密共有三种形式，分为AES 128（128-bit 长度加密），AES 192（192-bit 长度加密）以及AES 256（256-bit 长度加密）。
●完整性校验对接收的数据进行检查,确保数据没有被篡改,主要使用hash算法(HMAC hashed message authentication code),包含MD5(message digest输出128bit校验结果);SHA-1(secure hash algorithm 1)输出160bits校验结果。
navicat ssh 隧道原理
navicat ssh 隧道原理英文回答：The principle behind Navicat SSH tunnel is to establish a secure connection between the local machine and the remote server through an encrypted tunnel. This allows the user to access the remote database securely as if it were on the local machine.When setting up an SSH tunnel in Navicat, the user needs to provide the SSH server information, including the host, port, username, and password. Navicat will then establish a secure SSH connection to the server.Once the SSH connection is established, Navicat will create a tunnel between the local machine and the remote server. This tunnel acts as a secure channel through which data can be transmitted between the two machines. The data sent through the tunnel is encrypted, ensuring its confidentiality and integrity.Navicat uses the SSH protocol to create the tunnel and encrypt the data. The SSH protocol provides a secure way to authenticate and encrypt communication between two machines. It uses public-key cryptography to authenticate the server and establish a shared secret key for encrypting the data.By using an SSH tunnel, Navicat allows users tosecurely access and manage remote databases withoutexposing sensitive information, such as usernames and passwords, to potential attackers. It provides a convenient and secure solution for remote database management.中文回答：Navicat SSH隧道的原理是通过建立一个加密隧道，在本地机器和远程服务器之间建立一个安全连接。
shadowsock 参数
shadowsock 参数英文回答：Shadowsocks is a popular proxy tool that allows users to bypass internet censorship and access blocked websites. It works by creating a secure connection between the user's device and a remote server, through which all internet traffic is routed. This helps to mask the user's IP address and encrypt their data, making it difficult for third parties to monitor or restrict their online activities.To use Shadowsocks, you need to have a Shadowsocks client installed on your device and a Shadowsocks server set up. The client and server communicate using a specific protocol, which is why it's important to ensure that both the client and server are compatible and using the same protocol version.The parameters you need to configure in the Shadowsocks client include the server address, server port, password,and encryption method. The server address is the IP address or domain name of the remote server you want to connect to. The server port is the port number on which the server is listening for incoming connections. The password is a shared secret between the client and server, used to authenticate and encrypt the communication. The encryption method determines how the data is encrypted and decrypted during transmission.For example, let's say I want to set up a Shadowsocks connection to access blocked websites in China. I wouldfirst need to find a Shadowsocks server located outside of China. I would then install a Shadowsocks client on my device and configure it with the server address, server port, password, and encryption method provided by the server administrator. Once everything is set up, I can connect to the Shadowsocks server and start browsing the internet without restrictions.中文回答：Shadowsocks是一种流行的代理工具，允许用户绕过互联网审查并访问被封锁的网站。
IPSEC
2000, Cisco Systems, Inc.
IPsec Protocol Suite-Page 4
IPsec Drivers
Until 1998 there was no universal mechanism for authentication, integrity, and confidentiality of Internet traffic
Scales to Service Provider levels IKE (Internet Key Exchange) for automated key management Interoperability with PKI (Public Key Infrastructure)
2000, Cisco Systems, Inc.
2000, Cisco SystSuite-Page 5
Data Protection Options
Application-Layer
Application Layers (5-7)
Transport/ Network Layers (3-4)
Access VPNs, Classic Site-to-site managed VPNs, Trusted MPLS VPNs Service Provider
Main Office POP
Business Partner Remote Office
2000, Cisco Systems, Inc.
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What is IPsec?
IPsec can be implemented anywhere In end hosts In intermediate systems (routers, firewalls) By anyone Service Providers Enterprises Should guarantee interoperability in multivendor environments
安全协议英文
•Eavesdropping（窃听）An Eavesdropping attack only passively observe messages.•Modification（篡改）A Modification attack alters or replaces some messages.•Replay / Preplay （重放）The attacker sends a message that it has observed as part of the protocol run.•Man-in-the-Middle（中间人）In a Man-in-the-Middle attack the attacker gets in the middle of a real run of a protocol. •Reflection（反射）Reflection attacks are a kind of replay attack that use a protocol against itself.•Denial of Service（拒绝服务）A DoS attack tries to use up all of a severs CPU or memory by making 1,000,000s ofrequests.•Typing Attack（类型攻击）In a typing attack the attacker passes off one type of message as being another. •Cryptanalysis（密码分析）•Cryptanalysis is the study of methods for obtaining the meaning of encrypted information, without access to the secret information which is normally required to do so.•certificate manipulation （证书操纵）modification of the certificate•protocol interaction （协议交互）using a new protocol to interact with a known protocolZero-knowledge proof （零知识证明）• A zero-knowledge proof is a way that a “prover” can prove possession of a certain piece of information to a “verifier” without revealing it.•Selective Disclosure（选择性泄露）（密钥传输）A key transport protocol or mechanism is a key establishment technique where one party creates or obtains a secret key, and then securely transfers it to the other(s)（密钥协商）A key agreement protocol or mechanism is a key establishment technique in which a shared secret key is derived by two (or more) parties as a function of information contributed by, or associated with, each of these, (ideally) such that no party can predetermine the resulting value.******************************概念比较*************************************** 重放与反射比特承诺与抛币：类似于比特承诺，但承诺是随机的。
sm2密钥交换协议流程
sm2密钥交换协议流程English Answer：SM2 Key Exchange Protocol.The SM2 key exchange protocol is a cryptographic protocol that allows two parties to establish a shared secret key over an insecure channel. The protocol is based on the SM2 elliptic curve cryptosystem, which is a Chinese national standard.The SM2 key exchange protocol consists of the following steps:1. The initiator (Alice) generates a random number a and computes the point Q = aG, where G is the base point of the SM2 curve.2. Alice sends the point Q to the responder (Bob).3. Bob generates a random number b and computes the point P = bG.4. Bob sends the point P to Alice.5. Alice computes the shared secret key K = aP.6. Bob computes the shared secret key K = bQ.The SM2 key exchange protocol is secure against eavesdropping and man-in-the-middle attacks. This is because the shared secret key is only known to Alice and Bob, and it cannot be computed by an eavesdropper who does not know the random numbers a and b.Chinese Answer：SM2 密钥交换协议。
tlcp密钥协商流程
tlcp密钥协商流程英文回答：TLCP Key Negotiation Process.The Telephony Link Control Protocol (TLCP) is a protocol used in Point-to-Point Protocol (PPP) to negotiate the encapsulation format for Layer 3 traffic and the encryption and authentication algorithms to be used. The TLCP key negotiation process is as follows:1. The client sends a TLCP Configure-Request message to the server, specifying the desired encapsulation format and encryption algorithms.2. The server sends a TLCP Configure-Ack message to the client, acknowledging the receipt of the Configure-Request message and specifying the agreed-upon encapsulation format and encryption algorithms.3. The client sends a TLCP Start-Up message to the server, indicating that it is ready to begin transmitting data.4. The server sends a TLCP Start-Up-Ack message to the client, indicating that it is also ready to begin transmitting data.The TLCP key negotiation process is secure because it uses a hash function to generate a shared secret key that is used to encrypt and authenticate the data traffic. The hash function is a one-way function, meaning that it is impossible to determine the input from the output. This makes it difficult for an attacker to intercept and decrypt the data traffic.中文回答：TLCP密钥协商流程。