B
    `	                 @   sZ   d dl mZ d dlmZmZmZ d dlmZ d dlm	Z	 d dl
mZ G dd dejZdS )	    )utils)AlreadyFinalizedUnsupportedAlgorithm_Reasons)_get_backend)HMACBackend)hashesc               @   sf   e Zd ZdeejdddZedZ	eddddZ
d d	d
dZed	ddZeddddZdS )HMACN)key	algorithmc             C   sj   t |}t|tstdtjt|tjs2td|| _	|| _
|| _|d kr`| j
|| j| _n|| _d S )Nz.Backend object does not implement HMACBackend.z*Expected instance of hashes.HashAlgorithm.)r   
isinstancer   r   r   ZBACKEND_MISSING_INTERFACEr   HashAlgorithm	TypeError
_algorithm_backend_keyZcreate_hmac_ctxr   _ctx)selfr
   r   backendctx r   R/home/dcms/DCMS/lib/python3.7/site-packages/cryptography/hazmat/primitives/hmac.py__init__   s    
zHMAC.__init__r   )datareturnc             C   s.   | j d krtdtd| | j | d S )NzContext was already finalized.r   )r   r   r   Z_check_byteslikeupdate)r   r   r   r   r   r   -   s    
zHMAC.update)r   c             C   s.   | j d krtdt| j| j| j| j  dS )NzContext was already finalized.)r   r   )r   r   r	   r   r   r   copy)r   r   r   r   r   3   s    
z	HMAC.copyc             C   s&   | j d krtd| j  }d | _ |S )NzContext was already finalized.)r   r   finalize)r   digestr   r   r   r   =   s
    

zHMAC.finalize)	signaturer   c             C   s:   t d| | jd krtd| jd  }| _|| d S )Nr   zContext was already finalized.)r   _check_bytesr   r   verify)r   r   r   r   r   r   r!   D   s
    
zHMAC.verify)NN)__name__
__module____qualname__bytesr   r   r   r   Zread_only_propertyr   r   r   r   r!   r   r   r   r   r	      s    

r	   N)Zcryptographyr   Zcryptography.exceptionsr   r   r   Zcryptography.hazmat.backendsr   Z'cryptography.hazmat.backends.interfacesr   Zcryptography.hazmat.primitivesr   ZHashContextr	   r   r   r   r   <module>   s
   