First things first: what is OpenSSL exactly? Well, it’s basically a bunch of code that helps you encrypt your data so no one can read it without the proper key. It’s like having a secret language that only certain people understand except instead of words and grammar rules, we use math to create our own little world where privacy is king (or queen).
Now, let me tell you something: if you want to learn how to use OpenSSL, be prepared for some serious brainpower. This stuff isn’t easy! You have to understand concepts like public key encryption, private key decryption, and digital signatures all of which sound like they belong in a sci-fi movie rather than your everyday life.
Just remember that OpenSSL is here to help you protect your data from prying eyes (and ears). And who knows? Maybe one day you’ll become an expert in this field and start working for a top-secret government agency or something equally exciting!
So, how do we use OpenSSL to encrypt our data? Well, first we need to create a key pair which is basically like having two keys that are mathematically related but can’t be used interchangeably. One of these keys (the public key) is for encryption and the other one (the private key) is for decryption.
To generate our key pair, we use the following command:
# This script generates a key pair using the OpenSSL tool.
# The key pair consists of a public key for encryption and a private key for decryption.
# The following command uses the OpenSSL tool to generate a private key with a length of 2048 bits and saves it in a file named "my_private_key.pem".
openssl genrsa -out my_private_key.pem 2048
This will create a new file called “my_private_key.pem” that contains our private key (which is kept secret) and some other information like the size of the key (in this case, it’s 2048 bits).
Next, we need to convert our private key into a public key format so we can share it with others who want to encrypt their data for us. To do that, we use another command:
# This script uses the openssl command to convert a private key into a public key format.
# The private key is stored in a file called "my_private_key.pem" and is kept secret.
# The key size is 2048 bits.
# The resulting public key will be stored in a file called "my_public_key.pem".
# The following command uses the openssl command to convert the private key into a public key format.
# The "-in" flag specifies the input file, in this case "my_private_key.pem".
# The "-outform" flag specifies the output format, in this case "PEM".
# The "-pubout" flag indicates that the output should be a public key.
# The ">" symbol redirects the output to a file called "my_public_key.pem".
openssl rsa -in my_private_key.pem -outform PEM -pubout > my_public_key.pem
This will create a new file called “my_public_key.pem” that contains our public key (which can be shared freely) and some other information like the size of the key and the name of the person who generated it (in this case, it’s us).
Now that we have both our private and public keys, let’s see how to use them for encryption. First, we need to create a new file called “my_secret_data.txt” that contains some sensitive information like passwords or credit card numbers (or whatever else you want to keep secret).
Next, we open up our terminal and navigate to the directory where our keys are stored:
# This script is used to navigate to the directory where our keys are stored.
# First, we need to create a new file called "my_secret_data.txt" that contains some sensitive information like passwords or credit card numbers (or whatever else you want to keep secret).
touch my_secret_data.txt # Creates a new file called "my_secret_data.txt"
# Next, we need to navigate to the directory where our keys are stored.
cd /path/to/your/keys # Changes the current working directory to the specified path
Then, we use OpenSSL to encrypt our data using our public key (which is shared with others who want to send us secure messages):
# This script uses OpenSSL to encrypt data using a public key
# The encrypted data can only be decrypted by the corresponding private key
# Use the rsautl command to encrypt data
# -enc flag specifies encryption mode
# -in flag specifies the input file, in this case "my_secret_data.txt"
# -pubin flag indicates that the key used for encryption is a public key
# -outform flag specifies the output format, in this case DER
# -inkey flag specifies the input key, in this case "my_public_key.pem"
# > redirects the output to a file called "encrypted_data.bin"
openssl rsautl -enc -in my_secret_data.txt -pubin -outform DER -inkey my_public_key.pem > encrypted_data.bin
This will create a new file called “encrypted_data.bin” that contains our encrypted data (which can only be decrypted using our private key).
Finally, we use OpenSSL to decrypt our data using our private key:
# This script uses OpenSSL to decrypt data using a private key and output it to a text file.
# First, we use the "openssl" command to access the OpenSSL tool.
# Then, we use the "rsautl" command to decrypt data using RSA algorithm.
# We specify the "-dec" flag to indicate that we want to decrypt data.
# Next, we use the "-in" flag to specify the input file, which is "encrypted_data.bin".
# We use the "-outform" flag to specify the output format, which is PEM.
# Then, we use the "-inkey" flag to specify the private key file, which is "my_private_key.pem".
# Finally, we use the ">" symbol to redirect the output to a new file called "decrypted_data.txt".
openssl rsautl -decrypt -in encrypted_data.bin -outform PEM -inkey my_private_key.pem > decrypted_data.txt
This will create a new file called “decrypted_data.txt” that contains our original data (which is now safe from prying eyes).
Who said learning about cryptography had to be boring?