Tools
OpenSSL Cheat Sheet
Print-ready cheat sheet for OpenSSL, organized for fast lookup, study, and desk-side use
Sample
What's in this cheat sheet
- Certificates
- Key Generation
- CSR
- Self-Signed
- Verification
- Encryption
- Hashing
- S/MIME
- Debugging
- Common Patterns
View Certificate Details
openssl x509 -in cert.pem -text -noout
openssl x509 -in cert.pem -subject -noout
openssl x509 -in cert.pem -dates -noout
openssl x509 -in cert.pem -issuer -noout
Convert Formats
# PEM to DER
openssl x509 -in cert.pem -outform DER \
-out cert.der
# DER to PEM
openssl x509 -in cert.der -inform DER \
-out cert.pem
Common Formats
PEM | Base64-encoded, `-----BEGIN CERTIFICATE-----` |
DER | Binary format, compact |
PFX / P12 | PKCS#12 bundle (cert + key + chain) |
CRT / CER | Certificate file (usually PEM or DER) |
Download the full cheat sheet for all sections, formatted for print
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