After upgrading to recent Linux distributions, SecureCRT often cannot establish SSH connections due to disabled legacy algorithms, but the issue can be resolved by updating SecureCRT or manually enabling modern key‑exchange and host‑key types in its settings.
The article uses a classroom love‑note scenario to illustrate how single‑key (symmetric) and double‑key (asymmetric) locks model modern cryptographic techniques, explaining key exchange, signatures, man‑in‑the‑middle attacks, and how HTTPS secures communication.
This guide explains how to use the ssh -Q command to list all OpenSSH-supported ciphers, cipher‑auth methods, key‑exchange algorithms, public‑key types, certificate keys, MACs, protocol versions, and signature algorithms, providing concrete command output and common examples for each category.
SSH (Secure Shell) is a widely used network security protocol that replaces insecure methods like Telnet and FTP by encrypting data and authenticating users, typically operating on port 22, and employing both symmetric and asymmetric encryption, key exchange, and various authentication methods such as passwords and public‑key pairs.
The article explains Diffie‑Hellman key agreement, detailing its 1976 origin, mathematical derivation, example walkthrough, and provides complete Java server and Android client code illustrating how two parties securely generate a shared secret over an insecure channel without transmitting the key.
This article explains Baidu’s custom bdtls security communication protocol for mini‑programs, detailing its TLS 1.3‑based architecture, DHE‑RSA key exchange, AES‑GCM encryption, implementation on both server and client sides, and the strategies used to achieve strong security, low latency, high availability, and extensibility.
This article introduces fundamental cryptography concepts, explaining how symmetric and asymmetric encryption work, the role of key exchange, the purpose and properties of hashing algorithms, and how digital signatures combine encryption and hashing to ensure data authenticity and integrity.
This article explains the SSH protocol, covering its default port, the step‑by‑step handshake process—including connection establishment, version and algorithm negotiation, key exchange, and user authentication methods—while also describing common clients like PuTTY and OpenSSH and the role of symmetric and asymmetric encryption.
This article provides a comprehensive introduction to cryptographic techniques, covering the goals of confidentiality, integrity and authentication, and detailing symmetric, asymmetric and hash algorithms, common implementations, their advantages and drawbacks, as well as key exchange methods and public key infrastructure.
This article explores the prevalence of weak passwords, introduces fundamental concepts of cryptography, explains symmetric encryption algorithms and their key distribution challenges, and demonstrates the Diffie‑Hellman key‑exchange process with a concrete example and a Python implementation of primitive‑root calculation.
This article distills practical design decisions for modern encrypted communication protocols—covering algorithm selection, versioning, PKI choices, library alternatives, replay protection, performance tuning, and latency considerations—while providing a concise appendix of fundamental cryptographic concepts and key references.
mmtls is a custom, lightweight secure communication protocol designed for WeChat that encrypts all client‑to‑server traffic, offering confidentiality, integrity, low latency, scalability, and forward secrecy by adapting TLS 1.3 concepts with optimized handshake, key‑exchange, record, and replay‑protection mechanisms.
