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Overview HTTP and HTTPS are the same application-layer protocol for transferring web resources, but HTTPS wraps every request and response in a TLS tunnel before it touches the network. That single layer determines whether credentials, cookies, and page content travel as plaintext visible to anyone on the path, or as ciphertext only the two endpoints can read. Comparison Diagram HTTPClientServerGET /login?pwd=hunter2visible to anyone on pathHTTPSClientServerx8f#9a2$qL0e...TLS-encrypted, tamper-evident Comparison Table Aspect HTTP HTTPS Default port 80 443 Connection establishment Single TCP three-way handshake TCP handshake plus a TLS handshake to negotiate cipher and exchange keys Certificate requirement None X.509 certificate issued by a trusted CA (or self-signed) required Data encryption Plaintext — headers, cookies, and body sent unencrypted Encrypted end-to-end using TLS/SSL symmetric ciphers Data integrity No built-in tamper detection MAC/AEAD in TLS detects in-transit tampering Browser indicator “Not secure” warning in modern browsers Padlock icon; no warning shown Performance overhead Lower — no crypto or extra round trip Slightly higher handshake/CPU cost, largely offset by TLS 1.3 and session resumption Typical use case Local development, internal tools on trusted networks, legacy static content Any production site, especially logins, payments, and APIs handling sensitive data Key Differences HTTPS is HTTP tunneled through TLS, not a separate application protocol HTTP traffic is readable in plaintext by anyone with network access; HTTPS traffic is encrypted HTTPS requires a valid certificate from a trusted CA to establish trust Modern browsers flag HTTP sites as not secure, pushing HTTPS as the default TLS 1.3 has shrunk the historical HTTPS handshake cost to near parity with plain TCP When to Use Each HTTP ...

Overview TCP and UDP are the two core transport-layer protocols used to move data between hosts, but they trade reliability for speed in opposite directions. TCP prioritizes reliable delivery through handshakes, acknowledgments, and retransmission, while UDP prioritizes low-latency delivery by sending datagrams with no setup or delivery guarantees. Choosing between them shapes how an application handles packet loss, ordering, and throughput. Comparison Diagram TCPUDPClientServerSenderReceiverSYNSYN-ACKACKconnection establishedDataACKDataACKFIN / ACK teardownDatagramDatagramlost, no retryDatagramDatagramno ACKs, no ordering Comparison Table Aspect TCP UDP Connection setup Three-way handshake (SYN, SYN-ACK, ACK) establishes a stateful connection before any data moves No handshake — sender transmits datagrams immediately with no prior negotiation Delivery guarantee Guaranteed via sequence numbers and acknowledgments; lost segments are detected and resent Best-effort only; lost packets vanish silently with no notification to either side Ordering Segments are reassembled in the original order regardless of arrival sequence No ordering guarantee; packets are delivered to the application in whatever order they arrive Flow & congestion control Dynamic window sizing and congestion-avoidance algorithms throttle the sender to match network capacity None; the application sends at whatever rate it chooses, independent of network conditions Error handling Checksum plus automatic retransmission recovers corrupted or missing segments Checksum only; corrupted or missing packets are simply dropped, not recovered Overhead & latency Larger 20+ byte header and handshake/ACK round trips add processing and latency Minimal 8-byte header and no round trips keep per-packet overhead and latency low Connection teardown Explicit four-way FIN/ACK exchange formally closes the connection on both sides No connection state exists, so transmission simply stops with nothing to tear down Key Differences TCP is connection-oriented, requiring a handshake before data flows, while UDP is connectionless TCP guarantees reliable delivery through acknowledgments and retransmission; UDP offers none TCP performs congestion control to avoid overwhelming the network; UDP has no such mechanism UDP’s minimal header overhead gives it consistently lower latency than TCP TCP preserves packet ordering end-to-end; UDP delivers packets in whatever order they arrive When to Use Each TCP ...