HTTPS is a network communication protocol that protects data transmission security

HTTPS

Introduction to HTTPS

HTTPS (Hypertext Transfer Protocol Secure) is a network communication protocol that protects data transmission security through encryption and authentication. It is an extension of the HTTP protocol and uses the SSL (Secure Sockets Layer) or TLS (Transport Layer Security) protocol to establish an encrypted connection to ensure the confidentiality and integrity of data during transmission.

Advantages of HTTPS:

• Data transmission security: By encrypting data, it prevents data from being stolen or tampered with.
• Authentication: Verify the server's identity through SSL certificates to prevent man-in-the-middle attacks .
• Support SEO: Search engines are more inclined to index websites that use HTTPS.
• Improve user trust: HTTPS indicates the security of the website and increases user trust in the website.

HTTPS is a network communication protocol that protects data transmission security and ensures data confidentiality and integrity through encryption and identity authentication. In today's Internet environment, the use of HTTPS has become an important means of protecting user privacy and data security.

HTTP Pain Points

1. "Statelessness" : The HTTP protocol is stateless, that is, the server does not save the client's state information. Each request is independent, and the server cannot know whether the two requests are from the same client. This leads to the need for additional mechanisms to maintain state information when dealing with application scenarios that need to maintain state (such as user login status), which increases the complexity of development and maintenance.
2. "Plain text transmission" : The HTTP protocol uses plain text transmission by default, and data is easily eavesdropped and tampered with during transmission. This is unsafe for the transmission of some sensitive information, and additional encryption mechanisms are required to ensure data security.
3. "Performance issues" : The HTTP protocol has some performance issues during transmission. For example, each request needs to establish and close a TCP connection, which will bring a large overhead. At the same time, in the request-response mode of the HTTP protocol, the client needs to actively initiate a request before the server can respond. This one-way communication method may cause some delays.
4. "Extensibility" : The HTTP protocol was not designed with the scale and complexity of the modern Internet in mind. With the development of the Internet, a large number of expansion requirements have emerged, such as supporting multimedia content and real-time communication. These requirements are beyond the original design scope of the HTTP protocol and need to be implemented through various expansion mechanisms, resulting in the complexity and inconsistency of the protocol.

Although the HTTP protocol is widely used in Internet applications, there are still some pain points that need to be addressed. In order to solve these problems, some new protocols and technologies have emerged, such as HTTPS, SPDY, HTTP/2, etc., to improve security, performance and scalability.

How HTTPS works

1. The client initiates an HTTPS request and connects to port 443 of the server.
2. The server sends its SSL certificate to the client.
3. The client verifies whether the server's certificate is credible, and if so, generates a random symmetric key .
4. The client encrypts the symmetric key using the server's public key and sends it to the server.
5. The server uses the private key to decrypt the symmetric key sent by the client.
6. The client and server use symmetric keys for encryption and decryption to ensure the security of data transmission.

encryption

Introduction to Encryption

Encryption refers to the process of converting raw data into unreadable ciphertext through a certain algorithm and key. Encryption can protect the confidentiality of data and prevent unauthorized persons from obtaining sensitive information. Common encryption algorithms include symmetric encryption and asymmetric encryption .

Symmetric encryption refers to an encryption algorithm that uses the same key for encryption and decryption. Common symmetric encryption algorithms include DES and AES. In symmetric encryption, the sender uses a key to encrypt the original data into ciphertext, and the receiver uses the same key to decrypt the ciphertext and restore it to the original data.

Asymmetric encryption refers to an encryption algorithm that uses different keys for encryption and decryption. Common asymmetric encryption algorithms include RSA and ECC. In asymmetric encryption, the sender uses the public key to encrypt the original data into ciphertext, and the receiver uses the private key to decrypt the ciphertext and restore it to the original data.

The security of encryption algorithms depends on the confidentiality of the key and the complexity of the algorithm . In order to enhance the security of encryption, technologies such as message authentication code (MAC) and digital signature are usually used to verify the integrity and authenticity of data.

Encryption is an important information security technology that can effectively protect the confidentiality and security of data by using appropriate encryption algorithms and key management methods.

Hash

Hash is an algorithm that maps data of any length to data of a fixed length. A hash function can convert input data into a fixed-length hash value, which is usually a number or a string. Hash functions have the following characteristics:

1. If you input the same data, the hash function will produce the same hash value.
2. If you input different data, the hash function will produce different hash values.
3. The output length of the hash function is fixed and is not affected by the length of the input data.

Hash functions are widely used in cryptography, data verification, data indexing, etc. Common hash functions include MD5, SHA-1, SHA-256, etc.

Applications of hash functions include:

• Data integrity check: By comparing the hash value of the data, it can be determined whether the data has been tampered with.
• Data index: Using the hash value of the data as an index allows for quick search and comparison of data.
• Password storage: Storing the hash value of the user's password in the database can increase the security of the password.

The mathematical representation of the hash function is: , where represents the hash value, represents the hash function, and represents the input data.

Symmetric encryption

Introduction to Symmetric Encryption

Symmetric encryption is an encryption algorithm that uses the same key to encrypt and decrypt data. In symmetric encryption, the sender and receiver use the same key to encrypt and decrypt data. The advantage of this encryption algorithm is that it is fast and suitable for encryption and decryption of large amounts of data. Common symmetric encryption algorithms include DES, AES, etc.

The process of symmetric encryption is as follows:

1. The sender uses the key to encrypt the plaintext to generate ciphertext.
2. The sender sends the ciphertext to the receiver.
3. The receiver uses the same key to decrypt the ciphertext and restore it to plaintext.

The advantage of symmetric encryption is that it is fast and suitable for encryption and decryption of large amounts of data. However, the disadvantage of symmetric encryption is that the key security is lower because both the sender and the receiver need to share the same key. If the key is leaked, then the attacker can easily decrypt the ciphertext.

In practical applications, symmetric encryption is often used in combination with asymmetric encryption. Asymmetric encryption is used for the secure transmission of keys, while symmetric encryption is used for the actual data encryption and decryption process. This balances speed and security.

Mathematical calculations involved in symmetric encryption

Symmetric encryption is an encryption algorithm that uses the same key for encryption and decryption. The mathematical calculations involved mainly include the following aspects:

1. Substitution and permutation: Symmetric encryption algorithms often use substitution and permutation operations to change the order and structure of plaintext to increase the complexity of encryption. These operations can be implemented through mathematical operations, such as using permutation tables or S-boxes for substitution and permutation.
2. XOR operation: XOR operation is a common operation in symmetric encryption algorithms. In the encryption process, plaintext and key are XORed to generate ciphertext; in the decryption process, ciphertext and key are XORed to restore plaintext. XOR operation is a simple binary operation that can be implemented through mathematical operations.
3. Modulo operation: Common mathematical operations in symmetric encryption algorithms also include modulo operation. Modulo operation is a remainder operation that can be used to limit the range of encryption results to ensure that the encrypted data is within the specified range.
4. Linear algebra operations: Some symmetric encryption algorithms (such as AES) use linear algebra operations, including matrix multiplication and matrix inversion, which are used to confuse and diffuse plaintext information.

The mathematical calculations involved in symmetric encryption include substitution and permutation, XOR operations, modular operations, and possible linear algebra operations. The purpose of these mathematical calculations is to increase the complexity of encryption, making the ciphertext difficult to crack.

DES algorithm

DES ( Data Encryption Standard ) is a symmetric encryption algorithm used to protect the confidentiality of data. It is a block cipher algorithm that divides plaintext data into fixed-length data blocks and converts plaintext into ciphertext through a series of encryption operations.

The main steps of the DES algorithm include initial permutation, 16 rounds of Feistel network, inverse initial permutation and key generation. In the initial permutation stage, the plaintext data undergoes a series of permutation and selection operations to obtain the data after initial permutation. Next, the data after initial permutation is subjected to multiple rounds of encryption operations through 16 rounds of Feistel network. Each round of encryption operation includes subkey generation, extended permutation, S box replacement, P box replacement and round key addition operation. Finally, the data after 16 rounds of encryption operation is converted into ciphertext through inverse initial permutation.

The security of the DES algorithm mainly depends on the length and confidentiality of the key. The DES algorithm uses a 56-bit key, but due to the short key length, it is no longer secure. Therefore, the commonly used encryption algorithms now have turned to using longer key lengths, such as the AES algorithm.

The encryption process of the DES algorithm can be expressed by the following formula:

Among them, represents ciphertext, represents encryption operation using a key, and represents plaintext.

The decryption process of the DES algorithm can be expressed by the following formula:

Among them, represents plaintext, represents the decryption operation using the key, and represents ciphertext.

The DES algorithm is a classic symmetric encryption algorithm that converts plaintext into ciphertext through a series of encryption operations, and can also be decrypted using the same key to restore ciphertext to plaintext. However, due to the short key length of the DES algorithm, it is no longer secure, and now commonly used encryption algorithms have turned to using longer key lengths.

Asymmetric encryption

Introduction to Asymmetric Encryption

Asymmetric encryption is an encryption algorithm that uses two keys: a public key and a private key. The public key is used to encrypt data, and the private key is used to decrypt data. The two keys are related, but the private key cannot be derived from the public key.

Asymmetric encryption works like this:

1. The sender encrypts the data using the receiver's public key.
2. The receiver uses his/her own private key to decrypt the encrypted data.

The advantage of asymmetric encryption is high security, because the private key is only known to the recipient, and no one else can decrypt the data. At the same time, asymmetric encryption can also be used for digital signatures to verify the integrity and authenticity of data.

Common asymmetric encryption algorithms include RSA, Diffie-Hellman, and Elliptic Curve Cryptography (ECC).

Below is the formula for the RSA algorithm:

Public key: Private key:

Encryption: Decryption:

Among them, is the plaintext, is the ciphertext, is the public key exponent, is the private key exponent, and is the modulus.

Asymmetric encryption plays an important role in protecting the security of data transmission and storage, and is widely used in network communications, e-commerce, digital certificates and other fields.

RSA Algorithm

The RSA algorithm is an asymmetric encryption algorithm that consists of three main steps: key generation, encryption, and decryption.

1. Key generation: The RSA algorithm uses two large prime numbers p and q to generate public and private keys. First, select two different prime numbers p and q and calculate their product n=p*q. Then, calculate the Euler function φ(n)=(p-1)*(q-1). Next, select an integer e such that 1<e<φ(n) and e and φ(n) are relatively prime. Finally, calculate the modular inverse element d of e, that is, the integer d that satisfies (e*d) mod φ(n) = 1. The public key is (n, e) and the private key is (n, d).
2. Encryption: To encrypt a message m, use the public key (n, e) to encrypt. Convert the message m to an integer M, satisfying 0<=M<n. Then, calculate the ciphertext c = M^e mod n.
3. Decryption: To decrypt the ciphertext c, use the private key (n, d) to decrypt. Calculate the plaintext m = c^d mod n.

The security of the RSA algorithm is based on the difficulty of factoring a large number, that is, the difficulty of factoring a large number into its prime factors. Therefore, the RSA algorithm is widely used in fields such as encrypted communications and digital signatures to protect the confidentiality and integrity of data.

The encryption and decryption process of the RSA algorithm can be expressed by the following formula:

Encryption: c = M^e mod n

Decryption: m = c^d mod n

Among them, M is plaintext, c is ciphertext, e is the public key exponent, n is the modulus, and d is the private key exponent.

Digital Certificates

Digital Signature

Digital signature is a technology used to verify data integrity and identity authentication. It uses an asymmetric encryption algorithm to encrypt and decrypt data.

The digital signature process is as follows:

1. The sender uses the private key to encrypt the data to be sent and generate a digital signature.
2. The sender sends the original data together with the digital signature to the receiver.
3. The receiver uses the sender's public key to decrypt the digital signature and obtain the decrypted data.
4. The receiver uses the same encryption algorithm to encrypt the original data to obtain the encrypted data.
5. The receiver compares the decrypted data with the encrypted data to see if they are consistent. If they are consistent, it means that the data integrity has not been tampered with and the sender's identity has been verified.

The role of digital signature is to ensure that data has not been tampered with during transmission and to verify the identity of the sender. It is widely used in e-commerce, network communications and other fields.

Digital Certificates

A digital certificate is a security tool used to verify and confirm identity in network communications. It is issued by an authoritative digital certificate authority (CA) to prove the identity and validity of a public key of an entity (such as a website, individual, or organization).

A digital certificate usually contains the following information:

• Subject information: the certificate holder's name, email address, etc.
• Public key information: The certificate holder's public key, used to encrypt and decrypt data.
• Certificate authority information: The name and public key of the CA that issued the certificate.
• Validity period: The certificate's effective date and expiration date.
• Digital signature: The CA signs the certificate using its own private key to ensure the integrity and authenticity of the certificate.

The verification process of a digital certificate is to verify the digital signature of the certificate by using the CA's public key. If the digital signature verification is successful, the authenticity and integrity of the certificate can be confirmed. In this way, users can trust the identity of the certificate holder and use its public key for secure communication.

In network communications, digital certificates are widely used in SSL/TLS protocols to protect the security of data transmission between websites and users. By using digital certificates, websites can prove their identity and encrypt communications between users and servers to prevent data from being stolen or tampered with.

A digital certificate is a security tool used to verify and confirm identity in network communications. It is issued by a CA and contains subject information, public key information, certificate authority information, validity period, digital signature, etc. It plays an important role in protecting the security of data transmission between websites and users.

Summarize

HTTPS is a protocol for secure communication over a computer network. It adds the SSL/TLS protocol to HTTP to ensure the security of communication.

The implementation principle of HTTPS is as follows:

1. The client initiates an HTTPS request: The client establishes a secure connection by sending an HTTPS request to the server.
2. Server sends certificate: The server sends its digital certificate to the client. The certificate contains the server's public key and other related information.
3. Client Verification Certificate: The client verifies the certificate sent by the server. Verification includes checking the legitimacy and validity period of the certificate. If the verification passes, the client proceeds to the next step.
4. Client generates a random key: The client generates a random symmetric key for subsequent encrypted communications.
5. The client encrypts the key using the server's public key: The client encrypts the generated random key using the server's public key and then sends the encrypted key to the server.
6. The server uses the private key to decrypt the key: The server uses its own private key to decrypt the received encryption key and obtains the random key generated by the client.
7. Establish a secure connection: The client and server use this random key to encrypt and decrypt subsequent communication content to ensure the security of communication.

HTTPS implements encryption and identity authentication of communication content, ensuring data security and integrity. At the same time, HTTPS can also prevent security threats such as man-in-the-middle attacks and data tampering.

The SSL/TLS protocol is a protocol used to protect network communication security. It is built on the transport layer and provides security and data integrity for the application layer.

The SSL/TLS protocol uses encryption algorithms and certificates to achieve communication security. It uses a combination of symmetric and asymmetric encryption algorithms to protect the confidentiality and integrity of data. At the beginning of communication, a handshake process will be carried out between the client and the server to negotiate the encryption algorithm and key, and then these keys will be used to encrypt and decrypt the communication data.

The SSL/TLS protocol also provides authentication capabilities by using digital certificates to verify the identity of the server. Digital certificates are issued by a trusted certificate authority and contain the server's public key and other related information. Clients can use certificates to verify the server's identity and ensure a secure connection with a legitimate server.

The SSL/TLS protocol protects the security of network communications and the integrity of data through encryption and authentication mechanisms. It is widely used in secure communications between web browsers and servers, as well as other application scenarios that require data security protection.