U
    EZh                     @   sd   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	rRd dl
mZ d dlmZ G dd dZdS )	    N)InvalidSignatureUnsupportedAlgorithm_Reasons)constant_time)CBC)Backend)ciphersc                   @   s\   e Zd ZdddddddZedddd	Zed
ddZd d
ddZeddddZdS )_CMACContextNr   zciphers.BlockCipherAlgorithm)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_freeZfrom_bufferZ	CMAC_Initlen_ctx)	selfr
   r   ctxregistryadapterZ
evp_cipherZkey_ptrres r#   p/home/aprabhat/apps/x.techxrdev.in/venv/lib/python3.8/site-packages/cryptography/hazmat/backends/openssl/cmac.py__init__   s4    
z_CMACContext.__init__)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$   update=   s    z_CMACContext.update)r   c                 C   sd   | j jd| j}| j jd| j}| j j| j||}| j |dk d | _| j j|d d  S )Nzunsigned char[]zsize_t *r   )	r   r   newr   r   Z
CMAC_Finalr   r   buffer)r   buflengthr"   r#   r#   r$   finalizeA   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$   copyK   s     z_CMACContext.copy)	signaturer   c                 C   s    |   }t||stdd S )NzSignature did not match digest.)r,   r   Zbytes_eqr   )r   r.   digestr#   r#   r$   verifyT   s    z_CMACContext.verify)N)	__name__
__module____qualname__r%   bytesr'   r,   r-   r0   r#   r#   r#   r$   r	      s    (
	r	   )typingZcryptography.exceptionsr   r   r   Zcryptography.hazmat.primitivesr   Z,cryptography.hazmat.primitives.ciphers.modesr   TYPE_CHECKINGZ,cryptography.hazmat.backends.openssl.backendr   r   r	   r#   r#   r#   r$   <module>   s   