Is it safe to put an encrypted file on a public web server

[Morten Kjærulff]

Hi,

I am new here, so sorry if I ask stupid questions.

I would like to use my unused storage on various web servers for
backup of my personal data, including the file with all my passwords.

Q1) Assume that I make a good passphrase, would it then be safe to
encrypt my backup with "gpg --symmetric ...", and put the backup where
anyone can get it?

man page for --symmetric say: "... The  default symmetric  cipher
used  is  CAST5,  but  may be chosen with the --cipher-algo option.
...". "gpg --version" says:

Home: ~/.gnupg
Supported algorithms:
Pubkey: RSA, RSA-E, RSA-S, ELG-E, DSA
Cipher: 3DES, CAST5, BLOWFISH, AES, AES192, AES256, TWOFISH
Hash: MD5, SHA1, RIPEMD160, SHA256, SHA384, SHA512, SHA224
Compression: Uncompressed, ZIP, ZLIB, BZIP2

Q2) Why would I use another cipher?

Q3) Are some ciphers stronger than others? If so, which is the best
for my purpose? (is it purpose dependent which is best?)

Cheers,
Morten