| 1234567891011121314151617 | var xor = require('buffer-xor')exports.encrypt = function (self, block) {  var data = xor(block, self._prev)  self._prev = self._cipher.encryptBlock(data)  return self._prev}exports.decrypt = function (self, block) {  var pad = self._prev  self._prev = block  var out = self._cipher.decryptBlock(block)  return xor(out, pad)}
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