46 lines
		
	
	
		
			1.2 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			46 lines
		
	
	
		
			1.2 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
var Buffer = require('safe-buffer').Buffer
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var MD5 = require('md5.js')
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/* eslint-disable camelcase */
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function EVP_BytesToKey (password, salt, keyBits, ivLen) {
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  if (!Buffer.isBuffer(password)) password = Buffer.from(password, 'binary')
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  if (salt) {
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    if (!Buffer.isBuffer(salt)) salt = Buffer.from(salt, 'binary')
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    if (salt.length !== 8) throw new RangeError('salt should be Buffer with 8 byte length')
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  }
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  var keyLen = keyBits / 8
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  var key = Buffer.alloc(keyLen)
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  var iv = Buffer.alloc(ivLen || 0)
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  var tmp = Buffer.alloc(0)
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  while (keyLen > 0 || ivLen > 0) {
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    var hash = new MD5()
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    hash.update(tmp)
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    hash.update(password)
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    if (salt) hash.update(salt)
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    tmp = hash.digest()
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    var used = 0
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    if (keyLen > 0) {
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      var keyStart = key.length - keyLen
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      used = Math.min(keyLen, tmp.length)
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      tmp.copy(key, keyStart, 0, used)
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      keyLen -= used
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    }
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    if (used < tmp.length && ivLen > 0) {
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      var ivStart = iv.length - ivLen
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      var length = Math.min(ivLen, tmp.length - used)
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      tmp.copy(iv, ivStart, used, used + length)
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      ivLen -= length
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    }
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  }
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  tmp.fill(0)
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  return { key: key, iv: iv }
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}
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module.exports = EVP_BytesToKey
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