# Python Crypt Module

The `crypt` module is an interface to the `crypt(3)` routine, which is a one-way hash function based on a modified DES algorithm; see the Unix man page for further details. Possible uses include storing hashed passwords so you can check passwords without storing the actual password.

**Note: The `crypt` module is deprecated as of Python 3.11 and was removed in Python 3.13. It is recommended to use `hashlib` for general hashing, or libraries like `bcrypt` or `passlib` for password hashing.**

## Importing the Module

```python
import crypt
```

## Hashing a Password

To hash a password, use the `crypt.crypt()` function. It takes the password and a "salt".

```python
import crypt

# In standard crypt, the salt is usually a two-character string
# chosen from the set [a-zA-Z0-9./].
hashed = crypt.crypt("password", "HX")
print(hashed)
```

If the salt is not provided, a random salt is generated (using the strongest method available).

```python
import crypt

hashed = crypt.crypt("password")
print(hashed)
```

## Verifying a Password

To verify a password, you hash the input password using the stored hash as the salt. If the result matches the stored hash, the password is correct.

```python
import crypt
import hmac

def verify_password(stored_hash, input_password):
    # crypt() takes the salt from the beginning of the stored hash
    return hmac.compare_digest(crypt.crypt(input_password, stored_hash), stored_hash)

# Example usage
password = "secret_password"
stored_hash = crypt.crypt(password)

if verify_password(stored_hash, "secret_password"):
    print("Password matches")
else:
    print("Password does not match")
```

## Generating Salts

The `crypt.mksalt()` function generates a salt of the specified method.

```python
import crypt

# Generate a salt using SHA-512
salt = crypt.mksalt(crypt.METHOD_SHA512)
print(salt)
```

[[programming/python/python]]