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