A different symmetric algo for gpgme

By default, gpg2 uses CAST5 for a symmetric encryption. Here

crypto = GPGME::Crypto.new()
r = crypto.encrypt "Hello world!\n", symmetric: true

r.read() will return CAST5 data.

How to change the default cipher algo to, for example, AES256?

Solution

Well, apparently it's not possible to change the cipher through the API, but is possible w/ an indirect trick.

Create a tmp directory /foo/bar & put in it gpg.conf file w/ the line:
```
personal-cipher-preferences aes256
```
Set a 'home' directory for gpgme (before GPGME::Crypto.new):
```
GPGME::Engine.home_dir = '/foo/bar'
```