I am using gpg to make encrypt a tar.gz.

• My first try uses --verbose --symmetric and then the decryption is done with --verbose --decrypt. The --verbose shows that encryption was done with CAST5 and then the decryption uses CAST5.
  • i check all the file contents as a sanity check
• My second try uses --verbose --cipher-algo AES256 --symmetric. But I don't change the decrypt command... but somehow it knows to use AES256.
  • i check all the file contents as a sanity check

how does gpg know which cipher is needed (in this case AES256 instead of the default CAST5?

p.s. Does gpg embed what cipher algorithm was used, yes/no? wouldn't it be "better" to not tell anyone what encryption type was used?