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24 lines
869 B
Ruby
24 lines
869 B
Ruby
module Encryption
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ENCRYPTION_KEY = [0x4A, 0x8F, 0x2C, 0xE1, 0x73, 0xB5, 0x96, 0x0D,
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0x5E, 0xA2, 0x3F, 0xC7, 0x81, 0x14, 0x6B, 0xD9]
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CHUNK_SIZE = 1 << 20
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def self.xor(data)
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key = ENCRYPTION_KEY.pack("C*")
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@full_chunk_key ||= (key * (CHUNK_SIZE / key.length)).unpack1("H*").to_i(16)
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full_chunk_key = @full_chunk_key
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result = String.new(capacity: data.bytesize, encoding: Encoding::BINARY)
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offset = 0
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while offset < data.bytesize
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chunk = data.byteslice(offset, CHUNK_SIZE)
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size = chunk.bytesize
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chunk_key = size == CHUNK_SIZE ? full_chunk_key : (key * (size / key.length + 1)).byteslice(0, size).unpack1("H*").to_i(16)
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xored = chunk.unpack1("H*").to_i(16) ^ chunk_key
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result << [xored.to_s(16).rjust(size * 2, "0")].pack("H*")
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offset += CHUNK_SIZE
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end
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return result
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end
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end
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