It was decided to use standard base64 instead of base64-url because
that's what the Go implementation did by default for a []byte.
Signed-off-by: Patrick Uiterwijk <patrick@puiterwijk.org>
My hardware TPM only supports AES128, so let's use that for now to
be more compatible.
The tpm_sym_def function does take a mutable ctx borrow, so that in
the future it can automatically detect the best supported symdef.
Signed-off-by: Patrick Uiterwijk <patrick@puiterwijk.org>