Shivam Sharma

SSH key authentication replaces passwords with cryptographic proof of identity. Here's the full authentication flow, how to configure it securely, and where misconfigurations create vulnerabilities.

Deep dive into AES-256 encryption covering the algorithm internals, modes of operation (GCM, CBC, CTR), implementation in OpenSSL, Python, Java, and Go, plus key management best practices.

Compare ECDHE and DHE key exchange protocols covering security levels, performance benchmarks, forward secrecy, TLS cipher suite selection, recommended curves, and server configuration.

Complete PKCS#11 integration guide covering the Cryptoki API, slots/tokens/sessions model, OpenSSL engine configuration, Java SunPKCS11, Python PyKCS11, and HSM vendor setup.

Learn what multi-factor authentication (MFA) is, how it works, types including TOTP, FIDO2, and certificate-based auth, NIST AAL levels, and enterprise deployment strategies.

Complete guide to Windows Hello for Business certificate trust deployment, PKI integration with AD CS, TPM key attestation, hybrid models, and troubleshooting common enrollment issues.

HIPAA requires encryption as an 'addressable' safeguard for protected health information. Here's what that actually means, what NIST standards apply, and where healthcare organizations fail on encryption.

Fix the Windows certificate chain trust error. Covers missing root CA, intermediate certificate gaps, AIA/CDP issues, GPO trust distribution, and manual import — with certutil verification commands.

Emergency fix for expired SSL/TLS certificates causing production outages. Immediate diagnosis with openssl, emergency renewal via Certbot or commercial CA, and deployment to Nginx, Apache, IIS, and load balancers.

Fix NET::ERR_CERT_COMMON_NAME_INVALID, SSL_ERROR_BAD_CERT_DOMAIN, and hostname mismatch errors. Covers SAN checking, wildcard rules, SNI issues, and certificate reissuance.