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pull.js
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pull.js
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var crypto = require('libp2p-crypto')
var through = require('pull-through')
var aes = require('./aes')
var x = module.exports = {}
x.EncryptStream = EncryptStream
x.DecryptStream = DecryptStream
function copy(a) {
var b = new Buffer(a.length)
a.copy(b, 0, 0, a.length)
return b
}
function EncryptStream(key) {
if (key.length != aes.KeyLength) {
throw new Error('key length must be ' + aes.KeyLength)
}
// use a randomly generated IV
var IV = crypto.randomBytes(aes.BlockSize)
var Cipher = aes.create(key, IV)
var wroteIV = false
return through(function(data) {
if (!wroteIV) {
this.queue(copy(IV))
wroteIV = true
}
if ('string' === typeof data)
data = new Buffer(data, 'utf8')
else if (!Buffer.isBuffer(data))
return this.emit('error', new Error('must be buffer'))
if (data.length === 0) return
var stream = this
Cipher.encrypt(data, function (err, ciphertext) {
if (err) return stream.emit('error', err)
stream.queue(ciphertext)
})
}, function (end) {
return this.queue(null)
})
}
function DecryptStream(key) {
if (key.length != aes.KeyLength) {
throw new Error('key length must be ' + aes.KeyLength)
}
var IV = new Buffer(0)
var Cipher = null
return through(function(data) {
if ('string' === typeof data)
data = new Buffer(data, 'binary')
else if (!Buffer.isBuffer(data))
return this.emit('error', new Error('must be buffer'))
if (data.length === 0) return
// still getting IV.
var remainingIV = aes.BlockSize - IV.length
if (remainingIV > 0) {
rIV = Buffer.from(data.slice(0, remainingIV)) // copy
IV = Buffer.concat([IV, rIV])
data = data.slice(remainingIV)
if (0 == aes.BlockSize - IV.length) {
// ok IV is ready. make the cipher.
Cipher = aes.create(key, IV)
}
}
if (data.length === 0) return
if (!Cipher) new Error("should not have gotten here...")
var stream = this
Cipher.decrypt(data, function (err, plaintext) {
if (err) return stream.emit('error', err)
stream.queue(plaintext)
})
}, function (end) {
return this.queue(null)
})
}