Managed to generate a first secret

Cargo.lock

@@ -19,6 +19,12 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d468802bab17cbc0cc575e9b053f41e72aa36bfa6b7f55e3529ffa43161b97fa"
 
+[[package]]
+name = "base32"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "23ce669cd6c8588f79e15cf450314f9638f967fc5770ff1c7c1deb0925ea7cfa"
+
 [[package]]
 name = "base64"
 version = "0.13.0"
@@ -260,6 +266,7 @@ checksum = "b1141d4d61095b28419e22cb0bbf02755f5e54e0526f97f1e3d1d160e60885fb"
 name = "totp_generator"
 version = "0.1.0"
 dependencies = [
+ "base32",
  "base64",
  "clap",
  "totp_rfc6238",

Cargo.toml

@@ -8,4 +8,5 @@ edition = "2018"
 [dependencies]
 totp_rfc6238 = "0.5.0"
 base64 = "0.13.0"
+base32 = "0.4.0"
 clap = { version = "3.1.6", features = ["derive"] }

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);
 }