Cryptographic operations

This guide shows how to perform cryptographic operations using Virgil CLI.

Generate private key

This command generates a private Key:

virgil keygen -o <file>  -p <password>

Flag	Description
-o <file>	Key file name. If omitted, stdout is used.
-p <password>	Use password to encrypt Private Key. If omitted (not recommended), private key will be generated without password.

Example

Alice generates herself a private key:

> virgil keygen -o alices_private_key  -p 12345678

To check if the private key has been created, she uses the command cat:

> cat alices_private_key
-----BEGIN ENCRYPTED PRIVATE KEY-----
MIGhMF0GCSqGSIb3DQ...rwZT3hvIIquoXoFMsgAcwq228oDzG77A=
-----END ENCRYPTED PRIVATE KEY-----

Extract public key

This command extracts a public Key from a private Key:

virgil key2pub -i <file> -o <file>  -p <password>

Flag	Description
-i <file>	Name of the file with private key which the public key must be exported from. If omitted, stdin is used.
-o <file>	Name of the file where the public key will be exported to. If omitted, stdout is used.
-p <password>	Use password to encrypt Private Key. If omitted (not recommended), private key will be generated without password.

Example

Alice extracts public key from her previously generated private key:

> virgil key2pub -i alices_private_key -o alices_public_key -p 12345678

Now she checks if the key was extracted using command cat:

> cat alices_public_key
-----BEGIN PUBLIC KEY-----
MCowBQYDK2VwAy...WLohNExC9g8olt6GovRck=
-----END PUBLIC KEY-----

Encrypt data

This command encrypts any data for the specified public key(s):

virgil encrypt  -i <file> -o <file>  -key <public_key_file_1> -key <public_key_file_2> ...

Flag	Description
-i <file>	Data to encrypt. If omitted, stdin is used.
-o <file>	Encrypted data. If omitted, stdout is used.
-key <public_key_file>	Public key file (could be many files).

Example

Alice wants to encrypt her secret_message file, so that only Bob could decrypt it. She uses Bob's public key for that:

> virgil secret_message  -i info -o encrypted_secret_message  -key bobs_public_key

Decrypt data

This command decrypts the encrypted data with a private Key:

virgil decrypt  -i <file> -o <file>  -key <private_key_file> -p <password>

Flag	Description
-i <file>	Data to decrypt. If omitted, stdin is used.
-o <file>	Decrypted data. If omitted, stdout is used.
-key <private_key_file>	Private key file.
-p <password>	Use password to decrypt Private Key.

Example

Bob decrypts the file previously encrypted with his public key using his private key:

> virgil decrypt  -i encrypted_secret_message  -o decrypted_secret_message  -key bobs_private_key -p 12345678

Sign data

This command signs data with a provided user’s private key:

virgil sign  -i <file> -o <file>  -key <private_key_file> -p <password>

Flag	Description
-i <file>	Data to sign. If omitted, stdin is used.
-o <file>	The signed data. If omitted, stdout is used.
-key <private_key_file>	Private key file.
-p <password>	Use password to decrypt Private Key.

Example

Alice signs a file using her private key to prevent it from being changed:

> virgil secret_message  -i info  -o signed_secret_message -key alices_private_key -p 12345678

Verify signature

This command signs data with a provided User’s Private Key:

virgil verify  -i <file> -s <file>  -key <public_key_file>

Flag	Description
-i <file>	Data to verify.
-s <file>	Signature file.
-key <public_key_file>	Public key file. If omitted, stdin is used.

Example

Bob verifies if the signature belongs to Alice using her public key:

> virgil verify  -i secret_message -s signed_secret_message  -key alices_public_key
Signature OK