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While Encrypting a File with a Password from the Command Line using OpenSSL is very useful in its own right, the real power of the OpenSSL library is its ability to support the use of public key cryptograph for encrypting or validating data in an unattended manner (where the password is not required to encrypt) is done with public keys. How to Generate & Use Private Keys using OpenSSL's Command Line Tool. These commands generate and use private keys in unencrypted binary (not Base64 “PEM”) PKCS#8 format. The PKCS#8 format is used here because it is the most interoperable format when dealing with software that isn't based on OpenSSL.
< Cryptography
- Oct 29, 2019 Convert idrsa to pem file. GitHub Gist: instantly share code, notes, and snippets. I had the same problem and fixed by adding -m PEM when generate keys. So the gen key command look like. Then you can get pem from your rsa private key. Openssl rsa -in idrsa -outform pem idrsa.pem @kollaesch doesn't seem to be the case.
- $ openssl rsa -pubout -in privatekey.pem -out publickey.pem writing RSA key A new file is created, publickey.pem, with the public key. It is relatively easy to do some cryptographic calculations to calculate the public key from the prime1 and prime2 values in the public key file. However, OpenSSL has already pre-calculated the public key.
Download and install the OpenSSL runtimes. If you are running Windows, grab the Cygwin package.
OpenSSL can generate several kinds of public/private keypairs.RSA is the most common kind of keypair generation.[1]
Other popular ways of generating RSA public key / private key pairs include PuTTYgen and ssh-keygen.[2][3]
Openssl Generate Ssh Public Key
Generate an RSA keypair with a 2048 bit private key[edit]
Execute command: 'openssl genpkey -algorithm RSA -out private_key.pem -pkeyopt rsa_keygen_bits:2048'[4] (previously “openssl genrsa -out private_key.pem 2048”)
e.g.
Make sure to prevent other users from reading your key by executing chmod go-r private_key.pem afterward.
Extracting the public key from an RSA keypair[edit]
Execute command: 'openssl rsa -pubout -in private_key.pem -out public_key.pem'
e.g.
A new file is created, public_key.pem, with the public key.
It is relatively easy to do some cryptographic calculations to calculate the public key from the prime1 and prime2 values in the public key file.However, OpenSSL has already pre-calculated the public key and stored it in the private key file.So this command doesn't actually do any cryptographic calculation -- it merely copies the public key bytes out of the file and writes the Base64 PEM encoded version of those bytes into the output public key file.[5]
Viewing the key elements[edit]
Openssl Generate Id_rsa Key Free
Execute command: 'openssl rsa -text -in private_key.pem'
All parts of private_key.pem are printed to the screen. This includes the modulus (also referred to as public key and n), public exponent (also referred to as e and exponent; default value is 0x010001), private exponent, and primes used to create keys (prime1, also called p, and prime2, also called q), a few other variables used to perform RSA operations faster, and the Base64 PEM encoded version of all that data.[6](The Base64 PEM encoded version of all that data is identical to the private_key.pem file).
Password-less login[edit]
Often a person will set up an automated backup process that periodically backs up all the content on one 'working' computer onto some other 'backup' computer.
Because that person wants this process to run every night, even if no human is anywhere near either one of these computers, using a 'password-protected' private key won't work -- that person wants the backup to proceed right away, not wait until some human walks by and types in the password to unlock the private key.Many of these people generate 'a private key with no password'.[7]Some of these people, instead, generate a private key with a password,and then somehow type in that password to 'unlock' the private key every time the server reboots so that automated toolscan make use of the password-protected keys.[8][3]
Further reading[edit]
- ↑Key Generation
- ↑Michael Stahnke.'Pro OpenSSH'.p. 247.
- ↑ ab'SourceForge.net Documentation: SSH Key Overview'
- ↑'genpkey(1) - Linux man page'
- ↑'Public – Private key encryption using OpenSSL'
- ↑'OpenSSL 1024 bit RSA Private Key Breakdown'
- ↑'DreamHost: Personal Backup'.
- ↑Troy Johnson.'Using Rsync and SSH: Keys, Validating, and Automation'.
- Internet_Technologies/SSH describes how to use 'ssh-keygen' and 'ssh-copy-id' on your local machine so you can quickly and securely ssh from your local machine to a remote host.
Retrieved from 'https://en.wikibooks.org/w/index.php?title=Cryptography/Generate_a_keypair_using_OpenSSL&oldid=3622149'
Research on using
ssh-keygen
or openssl
to generate public/private keyswhich a Java application can use.This assumes that the key files are serialized Java objects, not the
ssh-keygen
generated files.References
Private RSA key uses
PKCS8EncodedKeySpec
[1]Public RSA key uses
X509EncodedKeySpec
[1]Openssl Generate Id_rsa Key Fob
The files generated by
ssh-keygen -t rsa -b 1024
need some parsingto remove newline characters as well as inline comments [2]. Furtherthe keys generated are 'bare' PKCS1 formatted whereas Java needsPKCS8 format [3]. You can tell a private key is in PKCS1 format because the commentin the file says '-----BEGIN RSA PRIVATE KEY-----'. For a PKCS8 format, the comment says'-----BEGIN PRIVATE KEY-----' without the RSS. So it looks like additional translation is needed tocreate files in PKCS#8 format [4]. Probably better to just use openssl [2, 5]:References
- Java Code Examples for
java.security.PrivateKey
. http://www.javased.com/index.php?api=java.security.PrivateKey - ParseRSAKeys.java https://gist.github.com/destan/b708d11bd4f403506d6d5bb5fe6a82c5
- Load an RSA private key in Java (algid parse error, not a sequence). https://stackoverflow.com/questions/15344125/load-a-rsa-private-key-in-java-algid-parse-error-not-a-sequence/29827944
- Why can't ssh-keygen export a public key in PEM PKCS8 format? https://crypto.stackexchange.com/questions/27913/why-can-ssh-keygen-export-a-public-key-in-pem-pkcs8-format
Openssl Generate Ssh-rsa Key
References
Openssl Generate Ssh Key
- Using OpenSSL to encrypt messages and files on Linux. https://linuxconfig.org/using-openssl-to-encrypt-messages-and-files-on-linux
- How to remove newline from output. https://stackoverflow.com/questions/35799684/how-to-remove-newline-from-output