100 lines
2.2 KiB
JavaScript
100 lines
2.2 KiB
JavaScript
var Buffer = require('safe-buffer').Buffer
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var Transform = require('stream').Transform
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var StringDecoder = require('string_decoder').StringDecoder
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var inherits = require('inherits')
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function CipherBase (hashMode) {
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Transform.call(this)
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this.hashMode = typeof hashMode === 'string'
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if (this.hashMode) {
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this[hashMode] = this._finalOrDigest
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} else {
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this.final = this._finalOrDigest
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}
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if (this._final) {
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this.__final = this._final
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this._final = null
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}
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this._decoder = null
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this._encoding = null
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}
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inherits(CipherBase, Transform)
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CipherBase.prototype.update = function (data, inputEnc, outputEnc) {
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if (typeof data === 'string') {
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data = Buffer.from(data, inputEnc)
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}
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var outData = this._update(data)
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if (this.hashMode) return this
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if (outputEnc) {
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outData = this._toString(outData, outputEnc)
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}
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return outData
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}
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CipherBase.prototype.setAutoPadding = function () {}
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CipherBase.prototype.getAuthTag = function () {
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throw new Error('trying to get auth tag in unsupported state')
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}
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CipherBase.prototype.setAuthTag = function () {
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throw new Error('trying to set auth tag in unsupported state')
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}
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CipherBase.prototype.setAAD = function () {
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throw new Error('trying to set aad in unsupported state')
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}
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CipherBase.prototype._transform = function (data, _, next) {
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var err
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try {
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if (this.hashMode) {
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this._update(data)
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} else {
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this.push(this._update(data))
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}
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} catch (e) {
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err = e
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} finally {
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next(err)
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}
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}
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CipherBase.prototype._flush = function (done) {
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var err
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try {
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this.push(this.__final())
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} catch (e) {
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err = e
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}
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done(err)
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}
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CipherBase.prototype._finalOrDigest = function (outputEnc) {
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var outData = this.__final() || Buffer.alloc(0)
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if (outputEnc) {
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outData = this._toString(outData, outputEnc, true)
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}
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return outData
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}
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CipherBase.prototype._toString = function (value, enc, fin) {
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if (!this._decoder) {
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this._decoder = new StringDecoder(enc)
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this._encoding = enc
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}
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if (this._encoding !== enc) throw new Error('can\'t switch encodings')
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var out = this._decoder.write(value)
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if (fin) {
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out += this._decoder.end()
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}
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return out
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}
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module.exports = CipherBase
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