crypto.js

var crypto = require('crypto');
var path = require('path');
var fs = require('fs');

var key = fs.readFileSync(path.join(process.env['HOME'], '.ssh/foo_rsa')).toString();
var pubkey = fs.readFileSync(path.join(process.env['HOME'], '.ssh/foo_rsa.pub')).toString();

var data = "abcdef"

var sign = crypto.createSign('RSA-SHA256');
sign.update(data);

var Sig = sign.sign(key, 'hex');

var verify = crypto.createVerify('RSA-SHA256');
verify.update(data);

console.log(verify.verify(pubkey, Sig, 'hex'));

$openssl genrsa -out foo_rsa 256
Generating RSA private key, 256 bit long modulus
......+++++++++++++++++++++++++++
...+++++++++++++++++++++++++++
e is 65537 (0x10001)

$openssl rsa -in foo_rsa -pubout -out foo_rsa.pub
writing RSA key

The problem is that the verify method always returns false.

$node --version
v0.9.0

$npm --version
1.1.44

Solution...

# generate a private key to use with your service
$openssl genrsa -out nodejitsu_rsa 1024

# create a public key to share with the service
$openssl rsa -in nodejitsu_rsa -pubout > nodejitsu_rsa.pub

var crypto = require('crypto');
var path = require('path');
var fs = require('fs');

var key = fs.readFileSync(path.join(process.env['HOME'], '.ssh/nodejitsu_rsa')).toString('ascii');
var pubkey = fs.readFileSync(path.join(process.env['HOME'], '.ssh/nodejitsu_rsa.pub')).toString('ascii');

var data = "abcdef";

var sign = crypto.createSign('SHA256');
sign.update(data);

var Sig = sign.sign(key, 'base64');

console.log(Sig);

var verify = crypto.createVerify('SHA256');
verify.update(data);

console.log(verify.verify(pubkey, Sig, 'base64'));