stricter idty name validation

Avoid phishing by requiring identity names to be ASCII alphanumeric and punctuation only.

Closes #47 (closed)

primitives/duniter/src/lib.rs

+// Copyright 2021 Axiom-Team
+//
+// This file is part of Substrate-Libre-Currency.
+//
+// Substrate-Libre-Currency is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, version 3 of the License.
+//
+// Substrate-Libre-Currency is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with Substrate-Libre-Currency. If not, see <https://www.gnu.org/licenses/>.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+/// Bound length; forbid trailing or double spaces; accept only ascii alphanumeric or punctuation or space
+pub fn validate_idty_name(idty_name: &[u8]) -> bool {
+    idty_name.len() >= 3
+        && idty_name.len() <= 64
+        && idty_name[0] != 32
+        && idty_name[idty_name.len() - 1] != 32
+        && idty_name
+            .iter()
+            .all(|c| c.is_ascii_alphanumeric() || c.is_ascii_punctuation() || *c == 32)
+        && idty_name
+            .iter()
+            .zip(idty_name.iter().skip(1))
+            .all(|(c1, c2)| *c1 != 32 || *c2 != 32)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_validate_idty_name() {
+        assert!(validate_idty_name(b"B0b"));
+        assert!(validate_idty_name(b"lorem ipsum dolor-sit_amet."));
+        assert!(!validate_idty_name(b" space"));
+        assert!(!validate_idty_name(b"space "));
+        assert!(!validate_idty_name(b"double  space"));
+        assert!(!validate_idty_name("non-ascii🌵".as_bytes()));
+        assert!(!validate_idty_name("ğune".as_bytes()));
+    }
+}