var crypto = require('crypto')
function checksum(str, algorithm, encoding) {
return crypto
.createHash(algorithm || 'md5')
.update(str, 'utf8')
.digest(encoding || 'hex')
}
checksum('This is my test text') // e53815e8c095e270c6560be1bb76a65d
checksum('This is my test text', 'sha1') // cd5855be428295a3cc1793d6e80ce47562d23def