Suppress the passphrase prompt in GPG command

Question

Edited Version

I have a question about GPG, but I write all of the process, maybe it will help someone.

I want to: Suppress the passphrase prompt in GPG command. I don't want to: use -c option (--symmetric).

I have 2 systems Linux and Windows. I want to send the data from Linux to Windows. I want to encrypt the data in Linux and decrypt in Windows.

• myFileOnLinux.txt is a file on Linux that I want to encrypt.
• [email protected] the UID of pair key.
• myPasswordPhrase is the password phrase.

I installed GPG on both and did the steps:

1. Generate a pair key in Windows:

   gpg --gen-key 

2. Change the key parameter in Windows:

   gpg --edit-key [email protected] 

   trust 5 expire 0 

3. Export the public keys:

   gpg -a --export [email protected] > public.key 

4. Send the public key to the Linux machine.

5. Import the public key in Linux.

   gpg --import public.key 

6. Change the trust parameter in Linux

   gpg --edit-key [email protected] 

   trust 5 

7. Encrypt a file in Linux

   gpg --output output.enc --encrypt --recipient [email protected] myFileOnLinux.txt 

8. Send the encrypted file to Windows.

9. Decrypt the file.

   gpg --batch --passphrase "myPasswordPhrase" -d -o test.dec output.enc 

In Windows with a popup window it asked me the Passphrase again. How can I avoid it?

Answer 1

After a lot of digging I found this command which disables the entry prompt on windows(works also for *nix systems):

--pinentry-mode=loopback 

The full command would be:

gpg --pinentry-mode=loopback --passphrase  "PASSWORD" -d -o "PATH\TO\OUTPUT" "PATH\TO\FILE.gpg" 

Answer 2

gpg --batch --import sec.key gpg -d --batch --passphrase mypassphrase encrypted_file.gpg 

the --batch flag supresses the passphrase prompt while importing keys as well as while decrypting the files.