7 Best Free RSA Key Generator Software For Windows

Here is a list of best free RSA key generator software for Windows. Using these freeware, you can generate RSA key pair i.e. a pair of public and private keys which are used in encryption and decryption. To create a pair of asymmetric keys, you can specify a key size such as 1024, 2048, 3072, 4096, 8192, 16384, etc. You can also export public and private (with a passphrase) as PEM private, PEM public, PK8, DER private, DER public, SSH2 public, etc. formats.

These are basically cryptography software, so you can also encrypt/decrypt text, files, and folders using these.

My Favorite RSA Key Generator Software For Windows

Hyper Crypt is one of my favorite RSA key generator as apart from creating asymmetric keys, you can also create symmetric keys, generate text, file, or folder hash values, encrypt/decrypt files and folder, and securely shred filesPuTTY Key Generator is also good as it lets you create RSA keys as well as DSA, ECDSA, ED25519, and SSH-1 keys.

You may also like some best free PGP Encryption Software, File Encryption Software, and Hard Disk Encryption Software for Windows.

Hyper Crypt

Hyper Crypt is a free portable RSA key generator for Windows. It is basically a free software to encrypt files and folder with AES-256 encryption. You can also use it to encrypt a phrase with RSA, AES-256, or One Time Pad algorithm, to compute text, file, or folder hash values, and to securely shred files and folders.

From its Tools section, you can find a Key Generator. Using this tool, you can generate symmetric, asymmetric, and Hyper Crypt Key (HCK) keys. To create RSA key pair, move to Asymmetric tab and select a key size (2048, 3072, 4096, 8192, or 16384). After that, hit the Generate button and specify the filename. It will then generate a pair of public and private keys in a matter of some time. The time taken to create RSA key pairs depends upon the key size.

It is a really nice and easiest to use RSA key generator in this list.

PuTTY Key Generator

PuTTY Key Generator is a dedicated key generator software for Windows. You can generate RSA key pair as well as DSA, ECDSA, ED25519, or SSH-1 keys using it.

In order to create a pair of private and public keys, select key type as RSA (SSH1/SSH2), specify key size, and click on Generate button. While the key generation process goes on, you can move mouse over blank area to generate randomness. As the keys are generated, the public key is displayed on the interface with key fingerprint and key comment. Also, you can directly copy and paste the public key into OpenSSH authorized key files from the interface. You can also save this public key to an individual file. The private key can be saved with a passphrase using the dedicated option.

Crypto Stuff

Crypto Stuff is another free portable cryptography software which can be used as an RSA key generator. To generate RSA key pairs, simply follow the below steps.

How to generate RSA key pair using this free software:

  • First, move to its Rsa (OAEP SHA1) tab.
  • From its Key generation section, specify key length, seed (Hex Buffer, Ascii String, Unicode String), and output location. You can also select one or more file formats to generate private and public keys, including DER binary (.bin), DER hex (.txt), and PEM (.txt openssl format).
  • Finally, hit the Generate button and you will get the RSA key pair in selected file format(s).

Using Crypto Stuff, you can generate or verify hash values. For this, it supports various algorithms including SHA256, MD5, Tiger, Whirlpool, CRC32C, BLAKE2b, etc. It can also encode a text using various algorithms like AES, Blowfish, IDEA, RC2, SEED, DES, SHARK, and many more. Additionally, you can convert a string to hex and vice versa using different encoding convention including ASCII, Unicode 16, and UTF8.

RSA Education Cryptosystem

RSA Education Cryptosystem is an RSA cryptography learning tool for Windows. You can use it to create an RSA key pair. It can be used in both Teach and Secure modes.

  • In Teach mode, you can specify two prime numbers and the value of e. After that, hit the Create keys button and then save private and public keys. You can then input a message to encrypt it. It will display the stepwise execution of the RSA algorithm in the dedicated section
  • In Learn mode, you can specify a custom key size and click on Create Key and then save them. You can then simply encrypt/decrypt a message.

The whole RSA execution process and encrypted/decrypted message can be copied to the clipboard or saved to a text file.

It is a portable RSA key generator software. Hence, you don’t need to go through an eventful installation process and can use it on the go.

X Certificate and Key management

X Certificate and Key management, as the name suggests, is a free software to create and manage X.509 certificates and private keys. Using it, you can create multiple RSA private keys from its Private Keys tab. Here is the simplified procedure to create RSA private key using this free software:

  • First, create a database with a passphrase to securely store created RSA private keys.
  • After that, in the Private Keys tab, click on New Key option and generate a private key by specifying key name and key size. This way, you can generate and store multiple RSA private keys to the database. You can view details of RSA key such as key, public exponent, private exponent, etc.
  • The created keys can also be exported in various formats including PEM private, PEM public, PK8, DER private, DER public, SSH2 public, etc.

This freeware comes with some other tools like OID Resolver, DH (Diffie-Hellman) Parameter Generator, etc.


Cryptermite is a free software to encrypt/decrypt files using AES, Serpent, TwoFish, BlowFish, Triple DES, and RSA encryption algorithms. It also lets you generate RSA keys of 1024, 2048, 4096, and 8196 bits. To generate RSA key pair, enter a password, then specify owner of keys in Input box, and then go to Generate RSA Keys menu and select a key size. The key pair will be generated in its download folder.

It provides some additional utilities to hide a file inside an image, extract hidden file from an image, manage passwords, create secure chat server, etc.


FileCryptoBot is one more software to encrypt and decrypt files. It is really simple to generate RSA key pair using it. You just have to hit the Generate KeyPair button and specify output location. After creating private and public keys, you can encrypt a file with the public key or decrypt a file with private key.

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Komal Srivastava

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