From becc5fd8aae56731fc7b7e8e6033ad2d1fe7cf13 Mon Sep 17 00:00:00 2001
From: Tiziano Zito <opossumnano@gmail.com>
Date: Mon, 22 Sep 2025 13:18:08 +0300
Subject: [PATCH 1/5] add minimal implementation

---
 minimal_auth.py | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 minimal_auth.py

diff --git a/minimal_auth.py b/minimal_auth.py
new file mode 100644
index 0000000..67064e5
--- /dev/null
+++ b/minimal_auth.py
@@ -0,0 +1,42 @@
+import json
+import sys
+
+def get_credentials():
+    username = input('Enter your username: ')
+    password = input('Enter your password: ')
+    return (username, password)
+
+def authenticate(username, password, pwdb):
+    return password == pwdb[username]
+
+def add_user(username, pwdb):
+    pwdb[username] = input(f'Enter password for {username}: ')
+    return pwdb
+
+def read_pwdb(pwdb_path):
+    try:
+        pwdb_file = open(pwdb_path, 'rt')
+        pwdb = json.load(pwdb_file)
+    except Exception:
+        pwdb = {}
+    return pwdb
+
+def write_pwdb(pwdb, pwdb_path):
+    pwdb_file = open(pwdb_path, 'wt')
+    json.dump(pwdb, pwdb_file)
+
+pwdb_path = 'pwdb.json'
+pwdb = read_pwdb(pwdb_path)
+
+if len(sys.argv) > 1:
+    pwdb = add_user(sys.argv[1], pwdb)
+    write_pwdb(pwdb, pwdb_path)
+else:
+    username, password = get_credentials()
+    if username not in pwdb:
+        print('Wrong username!')
+    else:
+        if authenticate(username, password, pwdb):
+            print('Successfully authenticated!')
+        else:
+            print('Wrong password!')

From 18579b0af2c69e948a8f212131498df67bf2f70d Mon Sep 17 00:00:00 2001
From: Tiziano Zito <opossumnano@gmail.com>
Date: Mon, 22 Sep 2025 13:25:55 +0300
Subject: [PATCH 2/5] do not leak valid usernames

---
 minimal_auth.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/minimal_auth.py b/minimal_auth.py
index 67064e5..8bdff7d 100644
--- a/minimal_auth.py
+++ b/minimal_auth.py
@@ -34,9 +34,9 @@ if len(sys.argv) > 1:
 else:
     username, password = get_credentials()
     if username not in pwdb:
-        print('Wrong username!')
+        print('Wrong username or password!')
     else:
         if authenticate(username, password, pwdb):
             print('Successfully authenticated!')
         else:
-            print('Wrong password!')
+            print('Wrong username or password!')

From 0aadaff89df3a2e80537dde1d857b3b166068515 Mon Sep 17 00:00:00 2001
From: victoris93 <shevchenko682@gmail.com>
Date: Mon, 22 Sep 2025 13:28:45 +0300
Subject: [PATCH 3/5] fixed that security problem

---
 minimal_auth.py | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/minimal_auth.py b/minimal_auth.py
index 8bdff7d..1950121 100644
--- a/minimal_auth.py
+++ b/minimal_auth.py
@@ -33,10 +33,7 @@ if len(sys.argv) > 1:
     write_pwdb(pwdb, pwdb_path)
 else:
     username, password = get_credentials()
-    if username not in pwdb:
+    if username not in pwdb or not authenticate(username, password, pwdb):
         print('Wrong username or password!')
     else:
-        if authenticate(username, password, pwdb):
-            print('Successfully authenticated!')
-        else:
-            print('Wrong username or password!')
+        print('Successfully authenticated!')

From 7548a834123579375d7a36ec381926594c6235bc Mon Sep 17 00:00:00 2001
From: victoris93 <shevchenko682@gmail.com>
Date: Mon, 22 Sep 2025 15:15:42 +0300
Subject: [PATCH 4/5] fixed the password visibility problem

---
 minimal_auth.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/minimal_auth.py b/minimal_auth.py
index 1950121..30fd41f 100644
--- a/minimal_auth.py
+++ b/minimal_auth.py
@@ -1,16 +1,17 @@
+import getpass
 import json
 import sys
 
 def get_credentials():
     username = input('Enter your username: ')
-    password = input('Enter your password: ')
+    password = getpass.getpass('Enter your password: ')
     return (username, password)
 
 def authenticate(username, password, pwdb):
     return password == pwdb[username]
 
 def add_user(username, pwdb):
-    pwdb[username] = input(f'Enter password for {username}: ')
+    pwdb[username] = getpass.getpass(f'Enter password for {username}: ')
     return pwdb
 
 def read_pwdb(pwdb_path):

From 0c28955b6ed9d1fe25b9a519e3ca7830b555cf39 Mon Sep 17 00:00:00 2001
From: victoris93 <shevchenko682@gmail.com>
Date: Mon, 22 Sep 2025 15:28:03 +0300
Subject: [PATCH 5/5] added comment to explain what getpass does

---
 minimal_auth.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/minimal_auth.py b/minimal_auth.py
index 30fd41f..9f535a7 100644
--- a/minimal_auth.py
+++ b/minimal_auth.py
@@ -1,4 +1,4 @@
-import getpass
+import getpass # hides types characters, very useful
 import json
 import sys