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- var Buffer = require('safe-buffer').Buffer
- function encryptByte (self, byteParam, decrypt) {
- var pad
- var i = -1
- var len = 8
- var out = 0
- var bit, value
- while (++i < len) {
- pad = self._cipher.encryptBlock(self._prev)
- bit = (byteParam & (1 << (7 - i))) ? 0x80 : 0
- value = pad[0] ^ bit
- out += ((value & 0x80) >> (i % 8))
- self._prev = shiftIn(self._prev, decrypt ? bit : value)
- }
- return out
- }
- function shiftIn (buffer, value) {
- var len = buffer.length
- var i = -1
- var out = Buffer.allocUnsafe(buffer.length)
- buffer = Buffer.concat([buffer, Buffer.from([value])])
- while (++i < len) {
- out[i] = buffer[i] << 1 | buffer[i + 1] >> (7)
- }
- return out
- }
- exports.encrypt = function (self, chunk, decrypt) {
- var len = chunk.length
- var out = Buffer.allocUnsafe(len)
- var i = -1
- while (++i < len) {
- out[i] = encryptByte(self, chunk[i], decrypt)
- }
- return out
- }
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