1 | 'use strict'
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2 |
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3 |
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4 |
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5 | var MAX_BYTES = 65536
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6 |
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7 |
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8 |
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9 | var MAX_UINT32 = 4294967295
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10 |
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11 | function oldBrowser () {
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12 | throw new Error('Secure random number generation is not supported by this browser.\nUse Chrome, Firefox or Internet Explorer 11')
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13 | }
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14 |
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15 | var Buffer = require('safe-buffer').Buffer
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16 | var crypto = global.crypto || global.msCrypto
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17 |
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18 | if (crypto && crypto.getRandomValues) {
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19 | module.exports = randomBytes
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20 | } else {
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21 | module.exports = oldBrowser
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22 | }
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23 |
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24 | function randomBytes (size, cb) {
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25 |
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26 | if (size > MAX_UINT32) throw new RangeError('requested too many random bytes')
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27 |
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28 | var bytes = Buffer.allocUnsafe(size)
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29 |
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30 | if (size > 0) {
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31 | if (size > MAX_BYTES) {
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32 |
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33 | for (var generated = 0; generated < size; generated += MAX_BYTES) {
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34 |
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35 |
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36 | crypto.getRandomValues(bytes.slice(generated, generated + MAX_BYTES))
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37 | }
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38 | } else {
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39 | crypto.getRandomValues(bytes)
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40 | }
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41 | }
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42 |
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43 | if (typeof cb === 'function') {
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44 | return process.nextTick(function () {
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45 | cb(null, bytes)
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46 | })
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47 | }
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48 |
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49 | return bytes
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50 | }
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