fix GPG error ubuntu backtrack 5

actually this error on my baby  backtrack 5 r3

root@bt:~# apt-get update
Get:1 http://32.repository.backtrack-linux.org revolution Release.gpg [198B]
Get:2 http://all.repository.backtrack-linux.org revolution Release.gpg [198B]
Get:3 http://source.repository.backtrack-linux.org revolution Release.gpg [198B]
Ign http://all.repository.backtrack-linux.org/ revolution/main Translation-en_US
Ign http://32.repository.backtrack-linux.org/ revolution/main Translation-en_US
Ign http://source.repository.backtrack-linux.org/ revolution/main Translation-en_US
Ign http://all.repository.backtrack-linux.org/ revolution/microverse Translation-en_US
Ign http://32.repository.backtrack-linux.org/ revolution/microverse Translation-en_US
Ign http://source.repository.backtrack-linux.org/ revolution/microverse Translation-en_US
Ign http://all.repository.backtrack-linux.org/ revolution/non-free Translation-en_US
Ign http://source.repository.backtrack-linux.org/ revolution/non-free Translation-en_US
Ign http://32.repository.backtrack-linux.org/ revolution/non-free Translation-en_US
Ign http://all.repository.backtrack-linux.org/ revolution/testing Translation-en_US
Ign http://source.repository.backtrack-linux.org/ revolution/testing Translation-en_US
Ign http://32.repository.backtrack-linux.org/ revolution/testing Translation-en_US
Get:4 http://all.repository.backtrack-linux.org revolution Release [13.5kB]
Ign http://all.repository.backtrack-linux.org revolution Release            
Get:5 http://source.repository.backtrack-linux.org revolution Release [13.5kB]
Get:6 http://32.repository.backtrack-linux.org revolution Release [5,041B] 
Ign http://32.repository.backtrack-linux.org revolution Release              
Ign http://source.repository.backtrack-linux.org revolution Release          
Hit http://all.repository.backtrack-linux.org revolution/main Packages
Hit http://32.repository.backtrack-linux.org revolution/main Packages
Hit http://source.repository.backtrack-linux.org revolution/main Packages    
Hit http://all.repository.backtrack-linux.org revolution/microverse Packages 
Hit http://32.repository.backtrack-linux.org revolution/microverse Packages
Hit http://32.repository.backtrack-linux.org revolution/non-free Packages    
Hit http://all.repository.backtrack-linux.org revolution/non-free Packages   
Hit http://32.repository.backtrack-linux.org revolution/testing Packages
Hit http://source.repository.backtrack-linux.org revolution/microverse Packages
Get:7 http://all.repository.backtrack-linux.org revolution/testing Packages [87.9kB]
Hit http://source.repository.backtrack-linux.org revolution/non-free Packages
Hit http://source.repository.backtrack-linux.org revolution/testing Packages 
Fetched 101kB in 6s (16.0kB/s)                                               
Reading package lists... Done
W: GPG error: http://all.repository.backtrack-linux.org revolution Release: The following signatures were invalid: BADSIG AB6DA34B475A6B7F BackTrack Repository Admin <emgent@backtrack-linux.org>
W: GPG error: http://32.repository.backtrack-linux.org revolution Release: The following signatures were invalid: BADSIG AB6DA34B475A6B7F BackTrack Repository Admin <emgent@backtrack-linux.org>
W: GPG error: http://source.repository.backtrack-linux.org revolution Release: The following signatures were invalid: BADSIG AB6DA34B475A6B7F BackTrack Repository Admin <emgent@backtrack-linux.org>



fix


Method 1
Try to run the following comamnds from terminal

$ sudo -i
# apt-get clean
# cd /var/lib/apt
# mv lists lists.old
# mkdir -p lists/partial
# apt-get clean
# apt-get update

Method 2
Try to run the following comamnds from terminal

sudo aptitude -o Acquire::http::No-Cache=True -o Acquire::BrokenProxy=true update
sudo apt-get update

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source: http://www.ubuntugeek.com/how-to-fix-the-ubuntu-gpg-error-badsig.html