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					51 lines
				
				1.5 KiB
			
		
		
			
		
	
	
					51 lines
				
				1.5 KiB
			| 
											3 years ago
										 | 'use strict' | ||
|  | 
 | ||
|  | // limit of Crypto.getRandomValues()
 | ||
|  | // https://developer.mozilla.org/en-US/docs/Web/API/Crypto/getRandomValues
 | ||
|  | var MAX_BYTES = 65536 | ||
|  | 
 | ||
|  | // Node supports requesting up to this number of bytes
 | ||
|  | // https://github.com/nodejs/node/blob/master/lib/internal/crypto/random.js#L48
 | ||
|  | var MAX_UINT32 = 4294967295 | ||
|  | 
 | ||
|  | function oldBrowser () { | ||
|  |   throw new Error('Secure random number generation is not supported by this browser.\nUse Chrome, Firefox or Internet Explorer 11') | ||
|  | } | ||
|  | 
 | ||
|  | var Buffer = require('safe-buffer').Buffer | ||
|  | var crypto = global.crypto || global.msCrypto | ||
|  | 
 | ||
|  | if (crypto && crypto.getRandomValues) { | ||
|  |   module.exports = randomBytes | ||
|  | } else { | ||
|  |   module.exports = oldBrowser | ||
|  | } | ||
|  | 
 | ||
|  | function randomBytes (size, cb) { | ||
|  |   // phantomjs needs to throw
 | ||
|  |   if (size > MAX_UINT32) throw new RangeError('requested too many random bytes') | ||
|  | 
 | ||
|  |   var bytes = Buffer.allocUnsafe(size) | ||
|  | 
 | ||
|  |   if (size > 0) {  // getRandomValues fails on IE if size == 0
 | ||
|  |     if (size > MAX_BYTES) { // this is the max bytes crypto.getRandomValues
 | ||
|  |       // can do at once see https://developer.mozilla.org/en-US/docs/Web/API/window.crypto.getRandomValues
 | ||
|  |       for (var generated = 0; generated < size; generated += MAX_BYTES) { | ||
|  |         // buffer.slice automatically checks if the end is past the end of
 | ||
|  |         // the buffer so we don't have to here
 | ||
|  |         crypto.getRandomValues(bytes.slice(generated, generated + MAX_BYTES)) | ||
|  |       } | ||
|  |     } else { | ||
|  |       crypto.getRandomValues(bytes) | ||
|  |     } | ||
|  |   } | ||
|  | 
 | ||
|  |   if (typeof cb === 'function') { | ||
|  |     return process.nextTick(function () { | ||
|  |       cb(null, bytes) | ||
|  |     }) | ||
|  |   } | ||
|  | 
 | ||
|  |   return bytes | ||
|  | } |