Modules/_cryptmodule.c

Source:

cpython 3.14 @ ab2d84fe1023/Modules/_cryptmodule.c ↗

crypt wraps the POSIX crypt(3) function for password hashing. Deprecated in 3.13 and removed in 3.13. Available only on Unix.

Map

Lines	Symbol	Role
1-50	crypt_crypt	Call system crypt() with word and salt
51-100	mksalt	Generate a random salt string for a given method
101-150	METHOD_*	METHOD_SHA512, METHOD_SHA256, METHOD_MD5, METHOD_CRYPT

Reading

crypt.crypt()

// CPython: Modules/_cryptmodule.c:38 crypt_crypt_impl
static PyObject *
crypt_crypt_impl(PyObject *module, const char *word, const char *salt)
{
    /* crypt(3) is not thread-safe; use the reentrant crypt_r if available */
#ifdef HAVE_CRYPT_R
    struct crypt_data data;
    memset(&data, 0, sizeof(data));
    Py_BEGIN_ALLOW_THREADS
    char *r = crypt_r(word, salt, &data);
    Py_END_ALLOW_THREADS
#else
    Py_BEGIN_ALLOW_THREADS
    char *r = crypt(word, salt);
    Py_END_ALLOW_THREADS
#endif
    if (r == NULL) return PyErr_SetFromErrno(PyExc_OSError);
    return PyUnicode_DecodeASCII(r, strlen(r), NULL);
}

Salt prefixes for method selection

// CPython: Modules/_cryptmodule.c:85 method constants
/* METHOD_SHA512: salt prefix '$6$rounds=N$' → SHA-512 with N rounds */
/* METHOD_SHA256: salt prefix '$5$rounds=N$' → SHA-256 with N rounds */
/* METHOD_MD5:    salt prefix '$1$'          → MD5-crypt */
/* METHOD_CRYPT:  2-char salt                → traditional DES */
/* Example: crypt.crypt('password', crypt.mksalt(crypt.METHOD_SHA512)) */

mksalt

# CPython: Lib/crypt.py:82 mksalt
def mksalt(method=None, *, rounds=None):
    """Generate a random salt of the given method."""
    if method is None: method = methods[0]
    s = method.prefix
    if method.ident in ('5', '6') and rounds is not None:
        s += 'rounds=%d$' % rounds
    # Append random characters from the base64 alphabet
    s += ''.join(_saltchars[os.urandom(1)[0] % len(_saltchars)]
                 for _ in range(method.salt_chars))
    return s

gopy notes

crypt was removed in Python 3.13 and is not in gopy's stdlib. For password hashing, hashlib provides PBKDF2 and bcrypt alternatives. The annotation covers the C module for completeness.