throughput of GnuPG symmetric ciphers

Ryan Malayter malayter at
Mon Aug 1 08:55:25 CEST 2005

I was going to use GnuPG for encrypting some very large backup files
on disk (~200 GB). However, the symmetric ciphers in GnuPG seem to be
fairly slow. Using the Windows build of 1.4.2, I only modest
throughputs piping GPG output from a fast 7200 RPM disk to >NUL (the
Windows equivalent of /dev/nul). (See table at end of email).

The process is not disk bound, since it uses 100% CPU and the
different algorithms take different times. Compression was turned off.

I have seen references on the net to fast software implementations of
AES that are an order of magnitude faster than GnuPG on a P4 (~1.5
Gbps). See

Has anyone made a GnuPG patch that includes faster implementations of
the core symmetric algorithms?

What other tools are people using for encrypting backups in datacenter
operations (as GnuPG seems to be too slow for this task)?

Thanks for any help,
Tests encrypting a 1 GB file on a 2.4 GHz Pentium 4.

Cipher Algorithm   Speed (Mbps)
CAST5              153.39
BLOWFISH           59.24
AES                102.26
3DES               64.59
AES-256            81.81
TWOFISH            124.49

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