OPENSSL-GENRSA(1ossl)

📦 version 3.5.0, in opensuse-leap 16.0

✨ OPENSSL-GENRSA(1ossl) ✨

okay bestie, so the OpenSSL girlies have this whole manual page and it's lowkey iconic. it's called openssl-genrsa and it's literally about generating an RSA private key. no cap. 💅

💖 NAME 💖

openssl-genrsa — generate an RSA private key, periodt. 🔑

🦋 SYNOPSIS 🦋

openssl genrsa [-help] [-out filename] [-passout arg] [-aes128]
[-aes192] [-aes256] [-aria128] [-aria192] [-aria256] [-camellia128]
[-camellia192] [-camellia256] [-des] [-des3] [-idea] [-F4] [-f4] [-3]
[-primes num] [-verbose] [-quiet] [-traditional] [-rand files]
[-writerand file] [-engine id] [-provider name] [-provider-path path]
[-provparam [name:]key=value] [-propquery propq] [numbits]

it's giving "long list of options" energy but don't panic, we're gonna go through every single one. slay. 🌈

🌸 DESCRIPTION 🌸

so basically, this command generates an RSA private key. that's it. that's the whole vibe. it's the glow-up your security needs, bestie. 🎀

✨ OPTIONS ✨

okay so here's where it gets juicy. every flag, every detail, ngl it's a lot but we're getting through it together. 🫶

  • -help — prints out a usage message. iconic for when you're lost. 🧭
  • -out filename — drops the key into the specified file. if you don't specify this argument, then standard output is used. no file? no problem, your terminal is the main character. 💀
  • -passout arg — this is the output file password source. for the whole format situation, go check openssl-passphrase-options(1). it's giving "look it up" energy but that's the truth. 📖
  • -aes128, -aes192, -aes256, -aria128, -aria192, -aria256, -camellia128, -camellia192, -camellia256, -des, -des3, -idea — these options encrypt the private key with the specified cipher before outputting it. so like, pick your fighter. if none of these options is specified, no encryption is used. and if encryption is used, a pass phrase is prompted for if it's not supplied via the -passout argument. 🔐
  • -F4, -f4, -3 — the public exponent to use, either 65537 or 3. the default is 65537. but heads up bestie, the -3 option has been deprecated. it's giving "don't use me" energy, fr fr. 🚫
  • -primes num — specify the number of primes to use while generating the RSA key. the num parameter must be a positive integer that is greater than 1 and less than 16. and if num is greater than 2, then the generated key is called a 'multi-prime' RSA key, which is defined in RFC 8017. so like, if you want extra primes, she can do that. 💅
  • -verbose — print extra details about the operations being performed. it's for when you want the tea on what's happening behind the scenes. ☕
  • -quiet — print fewer details about the operations being performed, which may be handy during batch scripts and pipelines. it's giving "less talk, more work" and honestly? valid. 🤫
  • -traditional — write the key using the traditional PKCS#1 format instead of the PKCS#8 format. it's a whole format choice, bestie. make it. 🎀
  • -rand files, -writerand file — see "Random State Options" in openssl(1) for details. iykyk. 🎲
  • -engine id — see "Engine Options" in openssl(1). also, this option is deprecated. so like, it had its moment but now we move on. 💀
  • -provider name, -provider-path path, -provparam [name:]key=value, -propquery propq — see "Provider Options" in openssl(1), provider(7), and property(7). that's the reference squad, go check them out. 📚
  • numbits — the size of the private key to generate in bits. this must be the last option specified. the default is 2048 and values less than 512 are not allowed. so like, don't even try to go below 512 because she won't allow it. periodt. 🔢

🔥 NOTES 🔥

okay so RSA private key generation essentially involves the generation of two or more prime numbers. when generating a private key, various symbols will be output to indicate the progress of the generation. let's decode the vibes:

  • A . represents each number which has passed an initial sieve test.
  • A + means a number has passed a single round of the Miller-Rabin primality test.
  • A * means the current prime starts a regenerating progress due to some failed tests.
  • A newline means that the number has passed all the prime tests (the actual number depends on the key size).

so like, every symbol is a little status update and you're just watching the glow-up happen in real time. it's honestly so satisfying. ✨

because key generation is a random process, the time taken to generate a key may vary somewhat. but in general, more primes lead to less generation time of a key. so like, sometimes she's fast, sometimes she's taking her time, and that's okay. we love a process. 💖

⭐ SEE ALSO ⭐

go check out these besties too:

they're all part of the same friend group, fr fr. 👑

Copyright 2000-2023 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <https://www.openssl.org/source/license.html>.

like, respect the rules bestie, that's the least we can do. 🙏

and that's the whole page! version 3.5.0, dated 2026-09-25, brought to you by the OpenSSL girlies. stay secure, slay always. 💅✨🔑

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