add base32 IDs

src/lib.rs

@@ -1,15 +1,32 @@
 use rand::{seq::IndexedRandom as _, Rng as _};
 
 pub fn main() {
-    let passphrase = create_passphrase(" ", 8);
-    println!("{passphrase}");
-    let pin = create_pin(8);
-    println!("{pin}");
+    println!("{}", create_passphrase(" ", 8));
+    println!("{}", create_pin(8));
+    println!("{}", create_base32(8));
+
     println!("Press Enter");
     let mut input = String::new();
     std::io::stdin().read_line(&mut input).ok();
 }
 
+/// Generates a Base32 string per RFC 4648, Section 6.
+///
+/// Wikipedia says this is the most popular encoding, and it's what
+/// `base32` in GNU coreutils uses.
+/// <https://en.wikipedia.org/wiki/Base32#Base_32_Encoding_per_%C2%A76>
+///
+/// This is useful for short IDs, e.g. bugs that aren't living in an issue
+/// tracker. 8 characters of Base32 is 40 bits of entropy, which is
+/// not enough for a password
+pub fn create_base32(len: usize) -> String {
+    let encoding: Vec<_> = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567".chars().collect();
+    assert_eq!(encoding.len(), 32);
+    let chars = (0..len).map(|_| *encoding.choose(&mut rand::rng()).unwrap());
+    String::from_iter(chars)
+}
+
+/// Generates a diceware passphrase
 pub fn create_passphrase(separator: &str, len: usize) -> String {
     let dice = Dice::default();
     let words: Vec<_> = (0..len).map(|_| dice.pick_word()).collect();