node-gpg

GNU Privacy Guard (GPG) bindings for node.js supporting public key cryptography, encryption, decryption, signing and verification. This is based off of the GnuPG Made Easy (GPGME) GPG C library, see its very good documentation for more information.

License

GNU GENERAL PUBLIC LICENSE v3, see the COPYING file in this directory.

Installation

npm install gpgme

Usage

• Also see the test.js file in this directory for example usage.
• Currently uses JavaScript strings for all data input and output.
• Uses ASCII Armor for all encrypted output.

Require gpg and initialize a new context.

var gpg = require('gpgme');

Verify

To verify a message with a signature. First generate the signature which can be done with the following in the shell (the -a indicates ASCII armor output).

sig=$(echo foo|gpg --detach-sign -a|sed ':a;N;$!ba;s/\n/\\\\n/g')
echo "{\"content\":\"foo\\\\n\", \"signature\":\"$sig\"}" |tee msg.json

Then load your message and signature to a JavaScript Object, and run the following (or run node test.js).

var msg = JSON.parse(fs.readFileSync('./msg.json', 'utf8'));
if(gpg.verify(msg.signature,msg.content))
  console.log("verification success");
else
  console.log("verification failure");

Decrypt

To decrypt an encrypted message. First generated encrypted content by running the following in a shell.

echo "secret contents"|gpg -e -r "Your GPG Name" -a|tee cipher.txt

Then run the following (or run node test.js).

var cipher = fs.readFileSync('cipher.txt', 'utf8');
var decrypted = gpg.decrypt(cipher);
console.log('decrypted content is "'+decrypted+'"');

To decrypt and verify a message. First generated encrypted content by running the following in a shell.

echo "secret signed contents"|gpg -s -e -r "Your GPG Name" -a \
  |tee signed-cipher.txt

Then run the following (or run node test.js).

var signed_cipher = fs.readFileSync('signed-cipher.txt', 'utf8');
var decrypted_and_verified = gpg.decryptAndVerify(signed_cipher);
console.log('decrypted and verified content is "'+decrypted_and_verified+'"');

Sign

To sign a message. First write a JSON hash holding the data to encrypt and the name of the signatory (this name will be used by GPG to lookup the key).

echo '{"signatory":"Your Name", "content":"foo\n"}' > sign.json

Then run the following (or run node test.js).

var sign = JSON.parse(fs.readFileSync('./sign.json', 'utf8'));
var signature = gpg.sign(sign.signatory, sign.content);
console.log('content "'+sign.content+
            '" signed by "'+sign.signatory+
            '" yields signature "'+signature+'"');

Encrypt

To encrypt a message. First write a JSON hash holding a list of the recipients and the message to encrypt.

echo '{"recipients":["Your Name"], "content":"foo\n"}' > encrypt.json

Then run the following (or run node test.js).

var encrypt = JSON.parse(fs.readFileSync('encrypt.json', 'utf8'));
var cipher = gpg.encrypt(encrypt.recipients, encrypt.content);
console.log('cipher text is "'+cipher+'"');

TODO

• add a context class to allow multiple simultaneous operations
• add a key class to allow key management to take place on the JS side of things
• add support for asynchronous operations w/callbacks (gpgme should make this straightforward)