Daniel Cao

Daniel Cao

Convert SSL Cer to PEM by OpenSSL

There are two major encoding schemes for X.509 certificates and keys: PEM (Base64 ASCII), and DER (binary). DER (Distinguished Encoding Rules) is a data object encoding schema that can be used to encode certificate objects into binary files. PEM (Privacy…

Create SSL Certificate With OpenSSL Command

A self-signed SSL certificate is a security certificate that is not signed by a certificate authority (CA). These certificates are easy to make and do not cost money. The Self-signed SSL certificate is mainly used for non-production applications or other…

Check P12 Pfx File With OpenSSL Pkcs12 Command

PKCS#12 files are commonly used to import and export certificates and private keys on Windows and macOS computers, and usually have the filename extensions .p12 or .pfx. OpenSSL on Linux If we are using Linux, we can install OpenSSL with…

Understanding SSL TLS handshake Process

An SSL/TLS handshake is a negotiation between two parties on a network – such as a browser and web server – to establish the details of their connection. The main purpose of an SSL handshake is to provide privacy and…

OpenSSL Commands Cheat Sheet

OpenSSL is the true Swiss Army knife of certificate management, and just like with the real McCoy, we spend more time extracting the nail file when what we really want is the inflatable hacksaw. We will find an overview of…

Check SSL Certificate Chain Order with Openssl

A SSL certificate chain is an ordered list of certificates, containing an SSL/TLS Certificate and Certificate Authority (CA) Certificates, that enable the receiver to verify that the sender and all CA’s are trustworthy. Each certificate contains information about its issuer.…

Capture TCP Packets with Tcpdump

TCP allows for the transmission of information in both directions. This means that computer systems that communicate over TCP can send and receive data at the same time, similar to a telephone conversation. The protocol uses segments (packets) as the…