Managed to generate a first secret

src/main.rs

@@ -1,3 +1,4 @@
+use base32::Alphabet;
 use clap::Parser;
 use totp_rfc6238::{HashAlgorithm, TotpGenerator};
 
@@ -27,8 +28,11 @@ fn main() {
         .set_hash_algorithm(HashAlgorithm::SHA1)
         .build();
 
-    let key = base64::decode(args.secret).unwrap();
+    let key = base32::decode(
+        Alphabet::RFC4648 { padding: true },
+        &args.secret,
+    ).unwrap();
     let code = totp_generator.get_code(&key);
 
-    println!("Secret len = {}", code);
+    println!("Secret = {}", code);
 }