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Diffstat (limited to 'node_modules/browserify-aes/decrypter.js')
-rw-r--r-- | node_modules/browserify-aes/decrypter.js | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/node_modules/browserify-aes/decrypter.js b/node_modules/browserify-aes/decrypter.js new file mode 100644 index 0000000..740b2e6 --- /dev/null +++ b/node_modules/browserify-aes/decrypter.js @@ -0,0 +1,124 @@ +var AuthCipher = require('./authCipher') +var Buffer = require('safe-buffer').Buffer +var MODES = require('./modes') +var StreamCipher = require('./streamCipher') +var Transform = require('cipher-base') +var aes = require('./aes') +var ebtk = require('evp_bytestokey') +var inherits = require('inherits') + +function Decipher (mode, key, iv) { + Transform.call(this) + + this._cache = new Splitter() + this._last = void 0 + this._cipher = new aes.AES(key) + this._prev = Buffer.from(iv) + this._mode = mode + this._autopadding = true +} + +inherits(Decipher, Transform) + +Decipher.prototype._update = function (data) { + this._cache.add(data) + var chunk + var thing + var out = [] + while ((chunk = this._cache.get(this._autopadding))) { + thing = this._mode.decrypt(this, chunk) + out.push(thing) + } + return Buffer.concat(out) +} + +Decipher.prototype._final = function () { + var chunk = this._cache.flush() + if (this._autopadding) { + return unpad(this._mode.decrypt(this, chunk)) + } else if (chunk) { + throw new Error('data not multiple of block length') + } +} + +Decipher.prototype.setAutoPadding = function (setTo) { + this._autopadding = !!setTo + return this +} + +function Splitter () { + this.cache = Buffer.allocUnsafe(0) +} + +Splitter.prototype.add = function (data) { + this.cache = Buffer.concat([this.cache, data]) +} + +Splitter.prototype.get = function (autoPadding) { + var out + if (autoPadding) { + if (this.cache.length > 16) { + out = this.cache.slice(0, 16) + this.cache = this.cache.slice(16) + return out + } + } else { + if (this.cache.length >= 16) { + out = this.cache.slice(0, 16) + this.cache = this.cache.slice(16) + return out + } + } + + return null +} + +Splitter.prototype.flush = function () { + if (this.cache.length) return this.cache +} + +function unpad (last) { + var padded = last[15] + if (padded < 1 || padded > 16) { + throw new Error('unable to decrypt data') + } + var i = -1 + while (++i < padded) { + if (last[(i + (16 - padded))] !== padded) { + throw new Error('unable to decrypt data') + } + } + if (padded === 16) return + + return last.slice(0, 16 - padded) +} + +function createDecipheriv (suite, password, iv) { + var config = MODES[suite.toLowerCase()] + if (!config) throw new TypeError('invalid suite type') + + if (typeof iv === 'string') iv = Buffer.from(iv) + if (config.mode !== 'GCM' && iv.length !== config.iv) throw new TypeError('invalid iv length ' + iv.length) + + if (typeof password === 'string') password = Buffer.from(password) + if (password.length !== config.key / 8) throw new TypeError('invalid key length ' + password.length) + + if (config.type === 'stream') { + return new StreamCipher(config.module, password, iv, true) + } else if (config.type === 'auth') { + return new AuthCipher(config.module, password, iv, true) + } + + return new Decipher(config.module, password, iv) +} + +function createDecipher (suite, password) { + var config = MODES[suite.toLowerCase()] + if (!config) throw new TypeError('invalid suite type') + + var keys = ebtk(password, false, config.key, config.iv) + return createDecipheriv(suite, keys.key, keys.iv) +} + +exports.createDecipher = createDecipher +exports.createDecipheriv = createDecipheriv |