[tor-commits] [torspec/master] Explain the reasoning behind the "x-tor-lzma" name.

ahf at torproject.org ahf at torproject.org
Wed May 3 20:12:50 UTC 2017


commit 7c572377db2d25c2f6cd90cad13d6b72d5449436
Author: Alexander Færøy <ahf at torproject.org>
Date:   Wed May 3 21:58:18 2017 +0200

    Explain the reasoning behind the "x-tor-lzma" name.
---
 proposals/278-directory-compression-scheme-negotiation.txt | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/proposals/278-directory-compression-scheme-negotiation.txt b/proposals/278-directory-compression-scheme-negotiation.txt
index 2c1ea69..475e4af 100644
--- a/proposals/278-directory-compression-scheme-negotiation.txt
+++ b/proposals/278-directory-compression-scheme-negotiation.txt
@@ -113,6 +113,13 @@ Target: N/A
   The "deflate", "gzip", and "identity" compression schemes must be
   supported by directory servers for backwards compatibility.
 
+  We use the name "x-tor-lzma" instead of just "x-lzma" because we
+  require a defined upper bound of memory usage that is available for
+  decompression of LZMA compressed data. The upper bound for memory
+  available for LZMA decompression is defined as 16 MB. This currently
+  means that will not use the LZMA compression scheme with a "preset"
+  value higher than 6.
+
   Additionally, when a client, that supports this proposals, makes a
   request to a directory document with the ".z"-suffix it must send an
   ordered set of supported compression schemes where the last elements



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