无法使用Node.js v0.10.18 @ Windows 7 64Bit解密

Question

I can't get crypto to work.

• windows 7 64Bit
• node.js v0.10.18

Encryption seems to work:

var fs = require('fs');

var img = new Buffer (fs.readFileSync('./image.png'), 'binary');

var crypto = require('crypto')
   , key = 'salt_from_the_user_document'
   , plaintext = img
   , cipher = crypto.createCipher('aes-256-cbc', key)
   , decipher = crypto.createDecipher('aes-256-cbc', key);

cipher.update(plaintext, 'binary', 'base64');
var encryptBinary = cipher.final('base64')
console.log('encrypted :', encryptBinary);

... but decryption not.

decipher.update(encryptBinary, 'base64', 'binary');
var decryptBinary = decipher.final('binary');
console.log('decrypted :', decryptBinary);

Same decryption problem with node-efs .

var efs = require('efs').init('aes-128-cbc', 'password');

// encrypt and write file
efs.writeFileSync('/tmp/example', 'hello world');

// decrypt and read file
efs.readFileSync('/tmp/example');

Same problem with file-encryptor .

This works (with strings only):

var crypto = require('crypto')
 , key = 'salt_from_the_user_document'
 , plaintext = 'password'
 , cipher = crypto.createCipher('aes-256-cbc', key)
 , decipher = crypto.createDecipher('aes-256-cbc', key);

cipher.update(plaintext, 'utf8', 'base64');
var encryptedPassword = cipher.final('base64')

decipher.update(encryptedPassword, 'base64', 'utf8');
var decryptedPassword = decipher.final('utf8');

console.log('encrypted :', encryptedPassword);
console.log('decrypted :', decryptedPassword);

Answer 1

The call to update also returns encrypted data, the call to final only returns the rest. Hence you need to concatenate output of each call to update and finally add the output of final . This is true for encryption as well as for decryption (and hashing, by the way).

Hence it needs to be something such as:

var encrypted = cipher.update(plaintext, 'binary', 'base64');
encrypted += cipher.final('base64');

Then it'll work.

Please note that the update and final functions are deprecated and the crypto module is now also stream-based and you might want to switch to the more modern approach anyway.