public-key-encryption

Encrypting data with a public key in Node.js

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A library is not necessary. Enter crypto. Here’s a janky little module you could use to encrypt/decrypt strings with RSA keys: var crypto = require(“crypto”); var path = require(“path”); var fs = require(“fs”); var encryptStringWithRsaPublicKey = function(toEncrypt, relativeOrAbsolutePathToPublicKey) { var absolutePath = path.resolve(relativeOrAbsolutePathToPublicKey); var publicKey = fs.readFileSync(absolutePath, “utf8”); var buffer = Buffer.from(toEncrypt); var encrypted = … Read more

Cracking short RSA keys

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Your teacher gave you: Public Key: (10142789312725007, 5) which means n = 10142789312725007 e = 5 where n is the modulus and e is the public exponent. In addition, you’re given Private Key: (10142789312725007, 8114231289041741) meaning that d = 8114231289041741 where d is the decryption exponent that should remain secret. You can “break” RSA by … Read more

Setting up OpenSSH for Windows using public key authentication

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Following are setup steps for OpenSSH shipped with Windows 10 v.1803 (April 2018 update. See comments to this post, it might not work with 1809). Server setup (elevated powershell): Install OpenSSH server: Add-WindowsCapability -Online -Name OpenSSH.Server~~~~0.0.1.0. Start agent and sshd services: Start-Service ssh-agent; Start-Service sshd (this will generate host keys and default configuration automatically in … Read more

Unable to load config info from /usr/local/ssl/openssl.cnf on Windows

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After installing OpenSSL I was required to create a new environment variable: Name: OPENSSL_CONF Value: C:\Program Files\OpenSSL\openssl.cnf In powershell: $env:OPENSSL_CONF = “${env:ProgramFiles}\OpenSSL\openssl.cnf” This value differs from previous installation versions (as seen in a previous edit of this post). Also, don’t forget to add the openssl binary folder ${env:ProgramFiles}\OpenSSL to your Path.