openssl

Generate RSA private key, 4096 bit

openssl genrsa 4096

Generate RSA private key, 2048 bit with password

openssl genrsa -aes256

Save the generated RSA private key

openssl genrsa -aes256 -out private.pem

Generate and save public key from private key

openssl rsa -in private.pem -outform PEM -pubout -out public.pem

---

Standard RSA SSL key used by most websites

RSA 2048 bit key

# Generate Certifcate Request
openssl req -new -newkey rsa:2048 -nodes -keyout shubhamtatvamasi.key -out shubhamtatvamasi.csr

# Self-Sign Certificate
openssl x509 -req -in shubhamtatvamasi.csr -signkey shubhamtatvamasi.key -out shubhamtatvamasi.crt -days 365

---

Self-Signed Certificate

Get the list of curves available

openssl ecparam -list_curves

Only secp384r1 and prime256v1 keys are compatible with modern browsers

Generate new private key

openssl ecparam -name secp384r1 -genkey -out ec_key.pem

Generate certificate

openssl req -new -key ec_key.pem -x509 -nodes -days 3650 -out cert.pem

---

OpenSSL DH Parameters

Generate Diffie-Hellman key exchange

openssl dhparam -out dhparam.pem 4096

add -dsaparam flag for faster key generation

---

Speed Test

ecdhp256 vs ecdhp384, operations per second

openssl speed ecdhp256 ecdhp384

---

Read information of your SSL certificate

openssl x509 -text -noout -in certificate.crt

---

Convert a PEM based file to JSON

awk 'NF {sub(/\r/, ""); printf "%s\\n",$0;}' cert-name.pem