knaccc / tweetnacl-tools

Tools for using TweetNaCl

tweetnacl-tools

These are some command line tools for using TweetNaCl by Prof Daniel J. Bernstein et al. There are three tools for encryption (make keys, encrypt, and decrypt), and three tools for signatures (make keys, sign, and verify).

Type make to compile the tools using gcc. The scripts go in bin/.

Encryption

tweetnacl-keypair

Generates Curve25519 public and secret keys.

Usage:

$ tweetnacl-keypair public.key secret.key

The public.key and secret.key files will contain 32 bytes each of the public and secret Curve25519 keys respectively. If either or both of the file names are given as - then the key will be printed as hexadecimal (64 bytes) with a trailing line feed ("\n") to stdout instead.

tweetnacl-encrypt

Encrypts data using Curve25519 public and secret keys.

Usage:

$ tweetnacl-encrypt sender.sec recipient.pub input.txt output.enc

The sender.sec file is the Curve25519 secret key of the person sending the message. The recipient.pub file is the Curve25519 secret key of the person receiving the message. input.txt contains the content of the message to be encrypted, and output.enc will be created to contain the encrypted message. Using - for the output filename will mean hexadecimal encrypted message content will be printed instead to stdout.

tweetnacl-decrypt

Decrypts data using Curve25519 public and secret keys.

Usage:

$ tweetnacl-decrypt sender.pub recipient.sec input.enc output.txt

The sender.pub file is the Curve25519 public key of the person who sent the message. The recipient.sec file is the Curve25519 secret key of the person who received the message. input.enc contains the encrypted message, and output.txt will be created to contain the decrypted message. Using - for the output filename will mean that the decrypted message content will be printed to stdout, verbatim.

Signatures

tweetnacl-sigpair

Creates public and secret keys suitable for signing.

Usage:

$ tweetnacl-sigpair sign.pub sign.sec

The sign.pub file is a public signature key, used for verification; and the sign.sec file is the counterpart private signature key, used for signing. Using - for either output filename will mean that the key is printed as hexadecimal with a trailing newline to stdout.

tweetnacl-sign

Signed a message using a secret signing key.

Usage:

$ tweetnacl-sign sign.sec message.txt message.signed

The sign.sec secret signature key is used to sign the message in message.txt and the output is placed into message.signed. If - is used for the output filename then it is printed verbatim to stdout.

tweetnacl-verify

Verifies a signed message relative to its public signature key.

Usage:

$ tweetnacl-verify sign.pub message.signed message.txt

The sign.pub public signature key is used to verify the signed message in message.signed. If the signature is verified, the message is placed into message.txt and the program exits with successful status 0. If the signature is not verified, an error message is printed to stderr and the program exists with the unsuccessful status 0. If the signature is verified and the message output file is - then the message is printed to stdout.

tweetnacl-derivepubkey

Derives the public key for the specified secret key

Usage:

$ tweetnacl-derivepubkey key.sec key.pub

Example

Encrypting and decrypting:

$ tweetnacl-keypair alice.pub alice.sec
$ tweetnacl-keypair bob.pub bob.sec
$ echo 'Secret message!' > message.txt
$ tweetnacl-encrypt alice.sec bob.pub message.txt secret.enc
$ tweetnacl-decrypt alice.pub bob.sec secret.enc -
Secret message!

Signing:

$ tweetnacl-sigpair sign.pub sign.sec
$ echo 'Verified message!' > message.txt
$ tweetnacl-sign sign.sec message.txt message.signed
$ tweetnacl-verify sign.pub message.signed -
Verified message!

Warning

Only the TweetNaCl portion of this software (tweetnacl.h and tweetnacl.c) was written by professional cryptographers. Use with caution, and the understanding that no professional security audit of this software has been conducted. This software comes with NO WARRANTY.

Please contribute a professional security audit if you are able to.

Acknowledgements

This software uses TweetNaCl version 20140427.

This software uses the devurandom flavour of the randombytes implementation from NaCl version 20110221.