U
    d                     @  sp   d dl mZ d dlZd dlmZmZmZ d dlmZ d dl	m
Z
 ejr^d dlmZ d dlmZ G dd	 d	ZdS )
    )annotationsN)InvalidSignatureUnsupportedAlgorithm_Reasons)constant_time)CBC)Backend)ciphersc                   @  s\   e Zd ZdddddddZddd	d
dZddddZd dddZdddddZdS )_CMACContextNr   zciphers.BlockCipherAlgorithmNone)backend	algorithmreturnc           	      C  s   | |stdtj|| _|j| _|| _|jd | _	|d kr| jj
}|t|tf }|| j|t}| jj }| j|| jjjk | jj|| jjj}| jj| j}| jj||t| j|| jjj}| j|dk || _d S )Nz#This backend does not support CMAC.      )Zcmac_algorithm_supportedr   r   ZUNSUPPORTED_CIPHER_backendkey_key
_algorithm
block_size_output_lengthZ_cipher_registrytyper   _libCMAC_CTX_newopenssl_assert_ffiZNULLgcCMAC_CTX_freefrom_bufferZ	CMAC_Initlen_ctx)	selfr   r   ctxregistryadapterZ
evp_cipherZkey_ptrres r&   M/tmp/pip-unpacked-wheel-ho9526s1/cryptography/hazmat/backends/openssl/cmac.py__init__   s4    
z_CMACContext.__init__bytes)datar   c                 C  s,   | j j| j|t|}| j |dk d S )Nr   )r   r   ZCMAC_Updater    r   r   )r!   r*   r%   r&   r&   r'   update?   s    z_CMACContext.update)r   c                 C  sd   | j jd| j}| j jd| j}| j j| j||}| j |dk d | _| j j|d d  S )Nzunsigned char[]zsize_t *r   )	r   r   newr   r   Z
CMAC_Finalr    r   buffer)r!   buflengthr%   r&   r&   r'   finalizeC   s    z_CMACContext.finalizec                 C  sV   | j j }| j j|| j jj}| j j|| j}| j |dk t	| j | j
|dS )Nr   )r"   )r   r   r   r   r   r   ZCMAC_CTX_copyr    r   r
   r   )r!   Z
copied_ctxr%   r&   r&   r'   copyM   s     z_CMACContext.copy)	signaturer   c                 C  s    |   }t||stdd S )NzSignature did not match digest.)r0   r   Zbytes_eqr   )r!   r2   digestr&   r&   r'   verifyV   s    z_CMACContext.verify)N)__name__
__module____qualname__r(   r+   r0   r1   r4   r&   r&   r&   r'   r
      s    (
	r
   )
__future__r   typingZcryptography.exceptionsr   r   r   Zcryptography.hazmat.primitivesr   Z,cryptography.hazmat.primitives.ciphers.modesr   TYPE_CHECKINGZ,cryptography.hazmat.backends.openssl.backendr   r	   r
   r&   r&   r&   r'   <module>   s   