When you download a digitally signed application from the Internet, you can easily verify its integrity by checking its digital certificates. If the file is modified then it would show an invalid digital certificate. If the file is same as the original creator intended, then the digital signatures would be intact and valid. You can also use these authenticode digital certificates to digitally sign your files, but they are very costly. If you cannot afford the commercially available certificates from companies like Comodo and Verisign, then you can use the free Encreep tool to create your own public-private-key pair to sign or encrypt your documents or messages.
The Encreep tool is a completely portable tool so it does not need to be installed. As you launch it, it shows options to load a public key, a private key or generate a pair. The public key can be used to encrypt and verify a signed file or message, while the private key can be used to decrypt or sign the files or messages.
You can click on the make new keys over the monster graphic to generate a new public-private key pair. You can add your name and email address in addition to a password to the keys, but all the fields are optional. The new pair of the generates keys is automatically loaded in Encreep.
You can send the public key to your friends so that they can verify your signed documents, files and messages and also encrypt the messages that they send to you. You have to keep your private key in a safe place because it is used to decrypt the messages and sign the documents.
The Encreep interface allows for easy use of the public and private keys. You can click on the encrypt link to enter your message or add a file to be encrypted using the public key. Similarly, you can decrypt any encrypted files or messages that someone sends your way.
Conclusion: The freeware Encreep is a portable Windows tool that allows you to easily make use of the public key cryptography to encrypt your messages and sign your files. It not only makes a fresh set of public-private keys, but also gives options to encrypt, decrypt, sign or verify signatures from single user interface.
You can download Encreep from https://www.encreep.com/.