uncompressing failed: Unknown compression algorithm

Lian Sebe lian.sebe at virusbulletin.com
Thu Jun 21 11:40:23 CEST 2018

Hi all,

I have a python script that ran very well, each day decrypting files.
Few days ago the script has stopped at a certain encrypted archive and
the process was hanging since.
I have drilled down and what happens is that gnupg is actually tripping
on a encrypted file. Trying the decryption outside python, just with the
regular command line:

gpg -vv --decrypt 2018-06-14.tbz.gpg > 2018-06-14.tbz

after requesting for the passphrase it says:

gpg: 3DES encrypted data
:compressed packet: algo=1
:literal data packet:
    mode b (62), created 1528912641, name="",
    raw data: unknown length
gpg: original file name=''
gpg: block_filter 0x186f090: read error (size=13002,a->size=13002)
:compressed packet: algo=42
gpg: uncompressing failed: Unknown compression algorithm

and then it hangs like this for days!

Now, it might be a defective encryption with this file, I don't care
much. I'd just like gnupg to move over the errors, i.e. exit after
finishing processing or after unsuccessfuly trying to process the file.

So, 2 questions:
1. Is it "normal" to hang like this or it is a bug ?
2. Is there any option I can pass to gnupg in command line so that it
goes on in case of errors instead of hanging?

I use this version on CentOS 7:
/gpg (GnuPG) 2.0.22//
//libgcrypt 1.5.3//
//Copyright (C) 2013 Free Software Foundation, Inc.//
//License GPLv3+: GNU GPL version 3 or later
//This is free software: you are free to change and redistribute it.//
//There is NO WARRANTY, to the extent permitted by law.//
//Home: ~/.gnupg//
//Supported algorithms://
//Pubkey: RSA, ?, ?, ELG, DSA//
//        CAMELLIA128, CAMELLIA192, CAMELLIA256//
//Hash: MD5, SHA1, RIPEMD160, SHA256, SHA384, SHA512, SHA224//
//Compression: Uncompressed, ZIP, ZLIB, BZIP2//


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