How is HTTPS security achieved?

Using TLS/SSL protocols for encrypting data between the client and server, ensuring confidentiality and integrity of transmitted information. Asymmetric encryption (RSA, ECC) is used for secure key exchange, while symmetric encryption (AES) is used for encrypting the data itself.

Using digital certificates issued by trusted certification authorities (CAs) to verify the authenticity of the server. The browser checks the trust chain of the certificate up to the root CA.

Hashing algorithms (SHA-256) are used to verify data integrity, ensuring they have not been altered during transmission.

Example of key exchange using asymmetric encryption:

// Client sends its key exchange parameters to the server.  
// Server responds with its key exchange parameters (e.g., public key).  
// Client generates a session secret key and encrypts it with the server's public key.  
// Encrypted session secret key is sent to the server.  
// Server decrypts the session secret key with its private key.  
// Now, the client and server share a common secret key for symmetric encryption of data.  

Example of data integrity verification using hashing:

// Before sending data, the sender computes the hash of the data.  
// Sender sends data and hash to the receiver.  
// Receiver receives data and hash.  
// Receiver computes the hash of the received data.  
// If the computed hash matches the received hash, the data has not been altered.  

Important aspects:

• TLS/SSL versions: Use of current and secure protocol versions (TLS 1.2, TLS 1.3). Outdated versions (SSL 2.0, SSL 3.0, TLS 1.0, TLS 1.1) have known vulnerabilities.
• Trustworthiness of the CA: Trust in the CA that issued the certificate.
• Server configuration: Proper configuration of TLS/SSL parameters on the server.
• Certificate validity: The certificate must be valid (not expired).
• Private Key Security: Secure storage of the server's private key.

Comparison of some encryption algorithms used in HTTPS:

Algorithm	Encryption type	Purpose	Examples of use in HTTPS
RSA	Asymmetric	Key exchange, signatures	Exchange of symmetric key
ECC (Elliptic Curve)	Asymmetric	Key exchange, signatures	More efficient key exchange
AES	Symmetric	Data encryption	Encrypting main traffic
ChaCha20-Poly1305	Symmetric	Encryption and authentication	Encrypting main traffic
SHA-256	Hashing	Data integrity verification	Integrity check

Together, these factors ensure a secure connection, protecting against interception, substitution, and falsification of data.

HTTPS security is achieved through a combination of three key mechanisms based on the TLS/SSL protocol:

1. Encryption: Data exchanged between the client and server is transformed into an unreadable format using encryption algorithms. This prevents interception and reading by third parties. Different types of encryption are used:
   • Symmetric encryption (e.g., AES) for encrypting the traffic itself after the connection is established.
   • Asymmetric encryption (e.g., RSA, Elliptic Curve Cryptography) for exchanging the symmetric key and verifying the server's authenticity.
2. Data integrity: Cryptographic hash functions (e.g., SHA-256) are used to create a unique "fingerprint" of the transmitted data. The recipient can compute the hash independently and compare it with the received hash. Any change in the data will alter the hash, signaling a breach of integrity.
3. Authentication: Digital certificates issued by trusted Certificate Authorities (CAs) are used for server authentication. The certificate contains the server's public key and is signed with the CA's private key. The browser trusts certain CAs, and if the certificate's signature is valid, the client can be confident it is communicating with the genuine server, not an attacker.

Thus, HTTPS ensures confidentiality, integrity, and authenticity of data during transmission.