Openssl Generate Key Pair Rsa

  

You may generate an RSA private key with the help of this tool. Additionally, it will display the public key of a generated or pasted private key. Generate ssh key for linux users.

Description

Getting the public key corresponding to a particular private key, through the methods provided for by OpenSSL, is a bit cumbersome. An easier way to do it is to use phpseclib, a pure PHP RSA.

RSA is an asymmetric encryption algorithm. With a given key pair, data that is encrypted with one key can only be decrypted by the other. This is useful for encrypting data between a large number of parties; only one key pair per person need exist. RSA is widely used across the internet with HTTPS.

  1. With a given key pair, data that is encrypted with one key can only be decrypted by the other. This is useful for encrypting data between a large number of parties; only one key pair per person need exist. RSA is widely used across the internet with HTTPS. To generate a key pair, select the bit length of your key pair and click Generate key.
  2. One way to do this is to generate a DER encoded key using OpenSSL's asn1parse command's -genconf option. You'll need to construct an input file for asn1parse -genconf to produce an RSA key in the standard format (per RFC 3447).
  3. May 29, 2016 The most effective and fastest way is to use command line tools: codeopenssl genrsa -out mykey.pem 4096 openssl rsa -in mykey.pem -pubout mykey.pub /codeIt’ll generate RSA key pair in code mykey.pem/code and code mykey.pub/code.

To generate a key pair, select the bit length of your key pair and click Generate key pair. Depending on length, your browser may take a long time to generate the key pair. A 1024-bit key will usually be ready instantly, while a 4096-bit key may take up to several minutes. For a faster and more secure method, see Do It Yourself below.

CryptoTools.net does not yet have a tool for facilitating the encryption and decryption of data using RSA, but you may Do It Yourself with the instructions below.

Do It Yourself

Openssl Generate Public And Private Key Pair

For these steps, you will need a command line shell with OpenSSL. Ideally, you should have a private key of your own and a public key from someone else. For demonstration, we will only use a single key pair.

Generate Private Key

Run this command to generate a 4096-bit private key and output it to the private.pem file. If you like, you may change the key length and/or output file.

Derive Public Key

Given a private key, you may derive its public key and output it to public.pem using this command. (You may also paste your OpenSSL-generated private key into the form above to get its public key.)

Encrypt Data

We can now use this key pair to encrypt and decrypt a file, data.txt.

Decrypt Data

Given the encrypted file from the previous step, you may decrypt it like so.

Openssl Generate Rsa Key Pair Windows

If you're using openssl_pkey_new() in conjunction with openssl_csr_new() and want to change the CSR digest algorithm as well as specify a custom key size, the configuration override should be defined once and sent to both functions:
<?php
$config = array(
'digest_alg' => 'sha1',
'private_key_bits' => 2048,
'private_key_type' => OPENSSL_KEYTYPE_RSA,
);
$privkey = openssl_pkey_new($config);
$csr = openssl_csr_new($dn, $privkey, $config);
?>

Although openssl_pkey_new() will accept the 'digest_alg' argument it won't use it, and setting the value has no effect unless you also set this value for openssl_csr_new(). The reason for this is that the $config array is acting as a drop-in replacement for the values found in the openssl.cnf file, so it must contain all of the override values that you need even if the function they're being sent to won't use them.
Also, if you change the 'digest_alg' to something like 'sha256' and still get an MD5 signed CSR check your openssl.cnf file to see whether the digest algorithm you want to use is actually supported.