openssl

Crypto/TLS swiss-army knife.

KaliParrotLinuxlow

pkg: openssl

The openssl CLI inspects certificates, tests TLS, and encrypts/hashes data — invaluable for TLS recon and crypto tasks.

Syntax

openssl {subcommand} [opts]

Example

openssl s_client -connect example.com:443 -servername example.com

Opens a TLS connection and prints the served certificate chain.

Options & flags

What each switch does. Toggle them in the builder below to assemble a command.

`s_client`	Connect to a TLS service and show the cert/chain.
`x509`	Parse/inspect a certificate.
`req`	Create a CSR or self-signed cert.
`enc`	Symmetric encrypt/decrypt.
`genrsa`	Generate an RSA private key.
`-connect` <host:443>	host:port for s_client.

Command builder

Tick options (and fill any values) to build a ready-to-copy command.

openssl

s_clientConnect to a TLS service and show the cert/chain.x509Parse/inspect a certificate.reqCreate a CSR or self-signed cert.encSymmetric encrypt/decrypt.genrsaGenerate an RSA private key.-connecthost:port for s_client.

Usage examples

openssl s_client -connect target.tld:443 -servername target.tld

Inspect the served TLS certificate.

openssl x509 -in cert.pem -noout -text

Decode a certificate file.

Advantages

One tool for many crypto tasks
Everywhere

Disadvantages

Dense subcommands/flags
Easy to misuse crypto

Related commands

curl

Transfer data with URLs (HTTP and many protocols).

sslscan

Quickly enumerate SSL/TLS ciphers and protocols.

Frequently asked questions

What is openssl used for?

The openssl CLI inspects certificates, tests TLS, and encrypts/hashes data — invaluable for TLS recon and crypto tasks.

What is an example openssl command?

A common example is: openssl s_client -connect example.com:443 -servername example.com — Opens a TLS connection and prints the served certificate chain.

Is openssl part of Kali Linux?

Yes. openssl ships with Kali Linux (and Parrot OS). If missing, install it with: sudo apt install openssl.

What category of security tool is openssl?

openssl is a Core Linux tool with a low-risk profile when run against a live target.

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