bitcore-lib-zcash/util/EncFile.js

60 lines
1.7 KiB
JavaScript

var fs = require('fs');
var crypto = require('crypto');
exports.readFileSync = function(enc_method, enc_passphrase, filename)
{
// read entire file into memory
var fileData = fs.readFileSync(filename, 'binary');
if (fileData.length < 32)
throw new Error("Crypted file " + filename + " truncated");
// separate into data, hmac parts
var fileCrypted = fileData.slice(0, -32);
var fileHmac = fileData.slice(-32);
// generate and verify HMAC
var hmac = crypto.createHmac('sha256', enc_passphrase);
hmac.update(fileCrypted);
var digest = hmac.digest('binary');
if (digest.toString() != fileHmac.toString())
throw new Error("Crypted file " + filename + " failed HMAC checksum verification");
// decrypt to plaintext
var decipher = crypto.createDecipher(enc_method, enc_passphrase);
var dec = decipher.update(fileCrypted, 'binary', 'binary');
dec += decipher.final('binary');
return dec;
};
exports.readJFileSync = function(enc_method, enc_passphrase, filename)
{
var raw = this.readFileSync(enc_method, enc_passphrase, filename);
return JSON.parse(raw);
};
exports.writeFileSync = function(enc_method, enc_passphrase, filename, data)
{
// encrypt to ciphertext
var cipher = crypto.createCipher(enc_method, enc_passphrase);
var crypted = cipher.update(data, 'binary', 'binary');
crypted += cipher.final('binary');
// compute HMAC
var hmac = crypto.createHmac('sha256', enc_passphrase);
hmac.update(crypted);
var digest = hmac.digest('binary');
fs.writeFileSync(filename, crypted + digest, 'binary');
return true;
};
exports.writeJFileSync = function(enc_method, enc_passphrase, filename, obj)
{
var raw = JSON.stringify(obj);
return this.writeFileSync(enc_method, enc_passphrase, filename, raw);
};