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30 lines
908 B
30 lines
908 B
var xor = require('buffer-xor') |
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var Buffer = require('safe-buffer').Buffer |
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var incr32 = require('../incr32') |
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function getBlock (self) { |
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var out = self._cipher.encryptBlockRaw(self._prev) |
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incr32(self._prev) |
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return out |
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} |
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var blockSize = 16 |
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exports.encrypt = function (self, chunk) { |
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var chunkNum = Math.ceil(chunk.length / blockSize) |
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var start = self._cache.length |
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self._cache = Buffer.concat([ |
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self._cache, |
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Buffer.allocUnsafe(chunkNum * blockSize) |
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]) |
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for (var i = 0; i < chunkNum; i++) { |
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var out = getBlock(self) |
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var offset = start + i * blockSize |
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self._cache.writeUInt32BE(out[0], offset + 0) |
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self._cache.writeUInt32BE(out[1], offset + 4) |
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self._cache.writeUInt32BE(out[2], offset + 8) |
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self._cache.writeUInt32BE(out[3], offset + 12) |
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} |
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var pad = self._cache.slice(0, chunk.length) |
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self._cache = self._cache.slice(chunk.length) |
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return xor(chunk, pad) |
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}
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