This article is about cryptography and asymmetric encryption / decyption.
Asymmetric (public / private key pair) and symmetric (one key to encrypt and decrypt).
– distribute your public key
– keep your private key secret and private 🙂
Ask people who want to send you a secret mail to encrypt it with the public key. Only you, the owner of the private key, are able to decrypt it.
Add the installation folder to your path and adjust the environment variable OPENSSL_CONF to point to your configuration file.
Asymmetric encryption of a file:
1. Create a private key and public key pair:
> openssl genrsa -out private.pem 1024
1a. Encrypt you private key:
> openssl rsa -in private.pem -des3 -out private-enc-key.pem
2. Extract the public key from this file (the public.pem, created below, can be freely distributed):
> openssl rsa -in private.pem -out public.pem -outform PEM -pubout
3. Encrypt a file:
> openssl rsautl -encrypt -inkey public.pem -pubin -in file.txt -out file_enc.txt
4. Decrypt the file with your private key:
> openssl rsautl -decrypt -inkey private.pem -in file_enc.txt -out decrypted.txt
Retrieve information about your private key (generated with genrsa command):
> openssl rsa -in privateKey.pem -text
Privacy Enhanced Email (PEM)