115 lines
2.8 KiB
JavaScript
115 lines
2.8 KiB
JavaScript
var MODES = require('./modes')
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var AuthCipher = require('./authCipher')
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var Buffer = require('safe-buffer').Buffer
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var StreamCipher = require('./streamCipher')
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var Transform = require('cipher-base')
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var aes = require('./aes')
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var ebtk = require('evp_bytestokey')
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var inherits = require('inherits')
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function Cipher (mode, key, iv) {
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Transform.call(this)
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this._cache = new Splitter()
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this._cipher = new aes.AES(key)
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this._prev = Buffer.from(iv)
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this._mode = mode
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this._autopadding = true
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}
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inherits(Cipher, Transform)
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Cipher.prototype._update = function (data) {
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this._cache.add(data)
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var chunk
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var thing
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var out = []
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while ((chunk = this._cache.get())) {
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thing = this._mode.encrypt(this, chunk)
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out.push(thing)
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}
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return Buffer.concat(out)
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}
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var PADDING = Buffer.alloc(16, 0x10)
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Cipher.prototype._final = function () {
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var chunk = this._cache.flush()
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if (this._autopadding) {
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chunk = this._mode.encrypt(this, chunk)
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this._cipher.scrub()
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return chunk
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}
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if (!chunk.equals(PADDING)) {
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this._cipher.scrub()
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throw new Error('data not multiple of block length')
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}
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}
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Cipher.prototype.setAutoPadding = function (setTo) {
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this._autopadding = !!setTo
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return this
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}
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function Splitter () {
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this.cache = Buffer.allocUnsafe(0)
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}
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Splitter.prototype.add = function (data) {
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this.cache = Buffer.concat([this.cache, data])
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}
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Splitter.prototype.get = function () {
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if (this.cache.length > 15) {
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var out = this.cache.slice(0, 16)
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this.cache = this.cache.slice(16)
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return out
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}
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return null
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}
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Splitter.prototype.flush = function () {
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var len = 16 - this.cache.length
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var padBuff = Buffer.allocUnsafe(len)
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var i = -1
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while (++i < len) {
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padBuff.writeUInt8(len, i)
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}
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return Buffer.concat([this.cache, padBuff])
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}
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function createCipheriv (suite, password, iv) {
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var config = MODES[suite.toLowerCase()]
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if (!config) throw new TypeError('invalid suite type')
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if (typeof password === 'string') password = Buffer.from(password)
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if (password.length !== config.key / 8) throw new TypeError('invalid key length ' + password.length)
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if (typeof iv === 'string') iv = Buffer.from(iv)
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if (config.mode !== 'GCM' && iv.length !== config.iv) throw new TypeError('invalid iv length ' + iv.length)
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if (config.type === 'stream') {
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return new StreamCipher(config.module, password, iv)
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} else if (config.type === 'auth') {
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return new AuthCipher(config.module, password, iv)
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}
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return new Cipher(config.module, password, iv)
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}
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function createCipher (suite, password) {
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var config = MODES[suite.toLowerCase()]
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if (!config) throw new TypeError('invalid suite type')
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var keys = ebtk(password, false, config.key, config.iv)
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return createCipheriv(suite, keys.key, keys.iv)
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}
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exports.createCipheriv = createCipheriv
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exports.createCipher = createCipher
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