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 ddlmZ ddlmZ dd	gZd
ZdZdZdd ZdZd"ddZdadad#dd	Zdd Zdd Zdd ZdZeeeedZd$ddZed d d! Z dS )%zg
passlib.utils.scrypt -- scrypt hash frontend and help utilities

XXX: add this module to public docs?
    )absolute_importN)warn)exc)to_bytes)PYPYvalidatescryptl    i?c                 C   sh   |dk r
t d| |dk rt d| || tkr"t d||f | dk s,| | d @ r2t d|  dS )aI  
    helper which validates a set of scrypt config parameters.
    scrypt will take ``O(n * r * p)`` time and ``O(n * r)`` memory.
    limitations are that ``n = 2**<positive integer>``, ``n < 2**(16*r)``, ``r * p < 2 ** 30``.

    :param n: scrypt rounds
    :param r: scrypt block size
    :param p: scrypt parallel factor
       zr must be > 0: r=%rzp must be > 0: p=%rz!r * p must be < 2**30: r=%r, p=%r   z%n must be > 1, and a power of 2: n=%rT)
ValueErrorMAX_RP)nrp r   uC:\Users\jesus\OneDrive\Desktop\erpjis_fastapi\backend\jisbackend\Lib\site-packages\passlib/crypto/scrypt/__init__.pyr   )   s   
   ?c                 C   s,   |d| d| d  t    }t|| }|S )a?  
    calculate memory required for parameter combination.
    assumes parameters have already been validated.

    .. warning::
        this is derived from OpenSSL's scrypt maxmem formula;
        and may not be correct for other implementations
        (additional buffers, different parallelism tradeoffs, etc).
           r   )UINT32_SIZEint)r   r   r   Zfudgemaxmemr   r   r   estimate_maxmemH   s   r   r
   r   c                 C   sZ   t ||| t| dd} t|dd}|dk rtd|tkr$tdt t| |||||S )a4  run SCrypt key derivation function using specified parameters.

    :arg secret:
        passphrase string (unicode is encoded to bytes using utf-8).

    :arg salt:
        salt string (unicode is encoded to bytes using utf-8).

    :arg n:
        integer 'N' parameter

    :arg r:
        integer 'r' parameter

    :arg p:
        integer 'p' parameter

    :arg keylen:
        number of bytes of key to generate.
        defaults to 32 (the internal block size).

    :returns:
        a *keylen*-sized bytes instance

    SCrypt imposes a number of constraints on it's input parameters:

    * ``r * p < 2**30`` -- due to a limitation of PBKDF2-HMAC-SHA256.
    * ``keylen < (2**32 - 1) * 32`` -- due to a limitation of PBKDF2-HMAC-SHA256.
    * ``n`` must a be a power of 2, and > 1 -- internal limitation of scrypt() implementation

    :raises ValueError: if the provided parameters are invalid (see constraints above).

    .. warning::

        Unless the third-party ``scrypt <https://pypi.python.org/pypi/scrypt/>``_ package
        is installed, passlib will use a builtin pure-python implementation of scrypt,
        which is *considerably* slower (and thus requires a much lower / less secure
        ``n`` value in order to be usuable). Installing the :mod:`!scrypt` package
        is strongly recommended.
    secret)paramsaltr
   zkeylen must be at least 1zkeylen too large, must be <= %d)r   r   r   
MAX_KEYLEN_scrypt)r   r   r   r   r   keylenr   r   r   r   k   s   )c                  C   s.   t rdnd} td|  tj ddlm} |jS )zD
    Load pure-python scrypt implementation built into passlib.
    
   d   zUsing builtin scrypt backend, which is %dx slower than is required for adequate security. Installing scrypt support (via 'pip install scrypt') is strongly recommendedr
   )ScryptEngine)r   r   r   ZPasslibSecurityWarningZ_builtinr#   execute)Zslowdownr#   r   r   r   _load_builtin_backend   s   r%   c               
   C   s   z	ddl m}  | W S  ty   Y nw zddl }W n& ty? } zdt|vr4tdtj W Y d}~dS W Y d}~dS d}~ww tdtj dS )z
    Try to import the ctypes-based scrypt hash function provided by the
    ``scrypt <https://pypi.python.org/pypi/scrypt/>``_ package.
    r   )hashNr   zJ'scrypt' package failed to import correctly (possible installation issue?)z5'scrypt' package is too old (lacks ``hash()`` method))r   r&   ImportErrorstrr   r   ZPasslibWarning)r&   r   errr   r   r   _load_cffi_backend   s(   
r*   c                     s6   zddl m  W n
 ty   Y dS w  fdd} | S )zf
    Attempt to load stdlib scrypt() implement and return wrapper.
    Returns None if not found.
    r   )r   Nc              	      s.   t }|dk rt|||} | ||||||dS )Nr   )passwordr   r   r   r   Zdklenr   )SCRYPT_MAXMEMr   )r   r   r   r   r   r    r   Zstdlib_scryptr   r   stdlib_scrypt_wrapper   s   z3_load_stdlib_backend.<locals>.stdlib_scrypt_wrapper)hashlibr   r'   )r.   r   r-   r   _load_stdlib_backend   s   r0   )stdlibr   builtinFc              	   C   s   | dkrdS | dkr't D ]} z	t| |dW   S  tjy!   Y qw tdt| }|s5td| f | }|sAtd|  |rEdS | a|adS )z
    set backend for scrypt(). if name not specified, loads first available.

    :raises ~passlib.exc.MissingBackendError: if backend can't be found

    .. note:: mainly intended to be called by unittests, and scrypt hash handler
    anyNdefaultdryrunzno scrypt backends availablezunknown scrypt backend: %rzscrypt backend %r not available)	backend_values_set_backendr   MissingBackendError_backend_loadersgetr   backendr   )namer6   loaderr&   r   r   r   r8      s(   

r8   r4   c                 C   s*   z	t | dd W dS  tjy   Y dS w )NTr5   F)r8   r   r9   )r=   r   r   r   _has_backend  s   r?   )r   )r
   r   )F)!__doc__
__future__r   logging	getLogger__name__logwarningsr   Zpasslibr   Zpasslib.utilsr   Zpasslib.utils.compatr   __all__r,   r   r   r   r   r   r   r<   r   r%   r*   r0   r7   dictr:   r8   r?   r   r   r   r   <module>   s>    

3!
