63 lines
1.5 KiB
JavaScript
63 lines
1.5 KiB
JavaScript
'use strict'
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var inherits = require('inherits')
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var Legacy = require('./legacy')
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var Base = require('cipher-base')
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var Buffer = require('safe-buffer').Buffer
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var md5 = require('create-hash/md5')
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var RIPEMD160 = require('ripemd160')
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var sha = require('sha.js')
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var ZEROS = Buffer.alloc(128)
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function Hmac (alg, key) {
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Base.call(this, 'digest')
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if (typeof key === 'string') {
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key = Buffer.from(key)
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}
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var blocksize = (alg === 'sha512' || alg === 'sha384') ? 128 : 64
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this._alg = alg
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this._key = key
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if (key.length > blocksize) {
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var hash = alg === 'rmd160' ? new RIPEMD160() : sha(alg)
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key = hash.update(key).digest()
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} else if (key.length < blocksize) {
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key = Buffer.concat([key, ZEROS], blocksize)
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}
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var ipad = this._ipad = Buffer.allocUnsafe(blocksize)
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var opad = this._opad = Buffer.allocUnsafe(blocksize)
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for (var i = 0; i < blocksize; i++) {
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ipad[i] = key[i] ^ 0x36
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opad[i] = key[i] ^ 0x5C
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}
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this._hash = alg === 'rmd160' ? new RIPEMD160() : sha(alg)
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this._hash.update(ipad)
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}
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inherits(Hmac, Base)
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Hmac.prototype._update = function (data) {
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this._hash.update(data)
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}
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Hmac.prototype._final = function () {
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var h = this._hash.digest()
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var hash = this._alg === 'rmd160' ? new RIPEMD160() : sha(this._alg)
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return hash.update(this._opad).update(h).digest()
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}
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module.exports = function createHmac (alg, key) {
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alg = alg.toLowerCase()
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if (alg === 'rmd160' || alg === 'ripemd160') {
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return new Hmac('rmd160', key)
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}
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if (alg === 'md5') {
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return new Legacy(md5, key)
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}
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return new Hmac(alg, key)
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}
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