From 9017da92b264c2263fb8a187d4a90aa958781fca Mon Sep 17 00:00:00 2001
From: Leo Alt <leo@ethereum.org>
Date: Tue, 9 May 2023 17:11:17 +0200
Subject: [PATCH] add password checker example

---
 riscv/tests/riscv.rs                          |   7 ++
 .../riscv_data/password_checker/Cargo.toml    |  11 ++
 .../riscv_data/password_checker/src/lib.rs    | 101 ++++++++++++++++++
 3 files changed, 119 insertions(+)
 create mode 100644 riscv/tests/riscv_data/password_checker/Cargo.toml
 create mode 100644 riscv/tests/riscv_data/password_checker/src/lib.rs

diff --git a/riscv/tests/riscv.rs b/riscv/tests/riscv.rs
index caebc5fdb..d5a7d1688 100644
--- a/riscv/tests/riscv.rs
+++ b/riscv/tests/riscv.rs
@@ -64,6 +64,13 @@ fn test_keccak() {
     verify_crate(case, vec![]);
 }
 
+#[test]
+#[ignore = "Too slow"]
+fn test_password() {
+    let case = "password_checker";
+    verify_crate(case, vec![]);
+}
+
 #[test]
 #[ignore = "Too slow"]
 // TODO: instead of just checking for panic, we could check the stdout for the actual message.
diff --git a/riscv/tests/riscv_data/password_checker/Cargo.toml b/riscv/tests/riscv_data/password_checker/Cargo.toml
new file mode 100644
index 000000000..d08d110fb
--- /dev/null
+++ b/riscv/tests/riscv_data/password_checker/Cargo.toml
@@ -0,0 +1,11 @@
+[package]
+name = "password_checker"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+runtime = { path = "../../../runtime" }
+
+[workspace]
diff --git a/riscv/tests/riscv_data/password_checker/src/lib.rs b/riscv/tests/riscv_data/password_checker/src/lib.rs
new file mode 100644
index 000000000..3a0af9b41
--- /dev/null
+++ b/riscv/tests/riscv_data/password_checker/src/lib.rs
@@ -0,0 +1,101 @@
+// Copyright 2023 RISC Zero, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#![no_std]
+
+pub struct PasswordRequest {
+    pub password: &'static str,
+    pub salt: [u8; 32],
+}
+
+#[no_mangle]
+pub fn main() {
+    let request = PasswordRequest {
+        // Uncomment \/ to see it fail
+        //password: "12345678",
+        password: "S00perSecr1t!!!",
+        salt: [0xaa; 32]
+    };
+
+    let policy = PasswordPolicy {
+        min_length: 3,
+        max_length: 64,
+        min_numeric: 2,
+        min_uppercase: 2,
+        min_lowercase: 2,
+        min_special_chars: 1,
+    };
+
+    assert!(policy.is_valid(&request.password));
+}
+
+struct PasswordPolicy {
+    pub min_length: usize,
+    pub max_length: usize,
+    pub min_uppercase: usize,
+    pub min_lowercase: usize,
+    pub min_numeric: usize,
+    pub min_special_chars: usize,
+}
+
+impl PasswordPolicy {
+    pub fn is_valid(&self, pw: &str) -> bool {
+        let metrics = PasswordMetrics::new(pw);
+        self.correct_length(pw)
+            && (metrics.numeric >= self.min_numeric)
+            && (metrics.uppercase >= self.min_uppercase)
+            && (metrics.lowercase >= self.min_lowercase)
+            && (metrics.special >= self.min_special_chars)
+    }
+
+    fn correct_length(&self, password: &str) -> bool {
+        password.len() > (self.min_length - 1) && password.len() < (self.max_length + 1)
+    }
+}
+
+struct PasswordMetrics {
+    pub numeric: usize,
+    pub special: usize,
+    pub uppercase: usize,
+    pub lowercase: usize,
+}
+
+impl PasswordMetrics {
+    pub fn new(password: &str) -> Self {
+        let mut numeric = 0;
+        let mut special = 0;
+        let mut uppercase = 0;
+        let mut lowercase = 0;
+        for ch in password.chars() {
+            if ch.is_ascii_digit() {
+                numeric += 1;
+            }
+            if ch.is_ascii_punctuation() {
+                special += 1;
+            }
+            if ch.is_ascii_uppercase() {
+                uppercase += 1;
+            }
+            if ch.is_ascii_lowercase() {
+                lowercase += 1;
+            }
+        }
+        PasswordMetrics {
+            numeric,
+            special,
+            uppercase,
+            lowercase,
+        }
+    }
+}