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    g!                     @   s   d dl mZmZmZ d dlmZ d dlmZmZm	Z	 d dl
mZ d dlmZ eejeejeejeejG dd deZdS )	    )absolute_importdivisionprint_function)utils)
InvalidTagUnsupportedAlgorithm_Reasons)ciphers)modesc                   @   sR   e Zd ZdZdZdZdd Zdd Zdd	 Zd
d Z	dd Z
dd ZedZdS )_CipherContext   r   i?c                 C   s  || _ || _|| _|| _d | _t| jtjr<| jjd | _	nd| _	| j j
 }| j j|| j j
j}| j j}z|t|t|f }W n2 ty   td|j|r|jn|tjY n0 || j ||}|| j jjkrd|}	|d ur|	d|7 }	|	d| j  7 }	t|	tjt|tjr6| j j|j}
njt|tjrV| j j|j}
nJt|tjrv| j j|j }
n*t|tjr| j j|j }
n
| j jj}
| j j
!||| j jj| j jj| j jj|}| j "|dk | j j
#|t$|j%}| j "|dk t|tj&r| j j
'|| j j
j(t$|
| j jj}| j "|dk |j)d ur| j j
'|| j j
j*t$|j)|j)}| j "|dk |j)| _| j j
!|| j jj| j jj| j j|j%|
|}| j "|dk | j j
+|d || _,d S )N   r   z6cipher {} in {} mode is not supported by this backend.zcipher {0.name} zin {0.name} mode z_is not supported by this backend (Your version of OpenSSL may be too old. Current version: {}.)r   )-_backendZ_cipher_mode
_operation_tag
isinstancer	   ZBlockCipherAlgorithmZ
block_size_block_size_bytes_libZEVP_CIPHER_CTX_new_ffigcZEVP_CIPHER_CTX_freeZ_cipher_registrytypeKeyErrorr   formatnamer   ZUNSUPPORTED_CIPHERNULLZopenssl_version_textr
   ZModeWithInitializationVectorfrom_bufferZinitialization_vectorZModeWithTweakZtweakZModeWithNonceZnonceZEVP_CipherInit_exopenssl_assertZEVP_CIPHER_CTX_set_key_lengthlenkeyGCMEVP_CIPHER_CTX_ctrlZEVP_CTRL_AEAD_SET_IVLENtagEVP_CTRL_AEAD_SET_TAGZEVP_CIPHER_CTX_set_padding_ctx)selfZbackendZciphermodeZ	operationctxregistryZadapterZ
evp_ciphermsgZiv_nonceres r+   N/usr/lib/python3/dist-packages/cryptography/hazmat/backends/openssl/ciphers.py__init__   s    




z_CipherContext.__init__c                 C   s2   t t|| j d }| ||}t|d | S )Nr   )	bytearrayr   r   update_intobytes)r%   databufnr+   r+   r,   updatez   s    z_CipherContext.updatec                 C   s   t |}t ||| j d k r:tdt || j d d}d}| jjd}| jjj|dd}| jj|}||kr|| }	|| }
t| j	|| }| jj
| j|	||
|}| j|dk ||7 }||d 7 }qp|S )Nr   z1buffer must be at least {} bytes for this payloadr   int *T)Zrequire_writable)r   r   
ValueErrorr   r   r   newr   min_MAX_CHUNK_SIZEr   EVP_CipherUpdater$   r   )r%   r1   r2   Ztotal_data_lenZdata_processedZ	total_outoutlenZ
baseoutbufZ	baseinbufZoutbufZinbufZinlenr*   r+   r+   r,   r/      s.    z_CipherContext.update_intoc                 C   sh  | j | jkr,t| jtjr,| jd u r,td| jj	
d| j}| jj	
d}| jj| j||}|dkr| j }|st| jtjrt| jj|d | jjj| jjj|d tdt| jtjr.| j | jkr.| jj	
d| j}| jj| j| jjj| j|}| j|dk | jj	|d d  | _| jj| j}| j|dk | jj	|d |d  S )Nz4Authentication tag must be provided when decrypting.zunsigned char[]r5   r   )errorszFThe length of the provided data is not a multiple of the block length.r   )r   _DECRYPTr   r   r
   ZModeWithAuthenticationTagr"   r6   r   r   r7   r   r   ZEVP_CipherFinal_exr$   Z_consume_errorsr    r   r   Z_lib_reason_matchZERR_LIB_EVPZ'EVP_R_DATA_NOT_MULTIPLE_OF_BLOCK_LENGTH_ENCRYPTr!   ZEVP_CTRL_AEAD_GET_TAGbufferr   ZEVP_CIPHER_CTX_cleanup)r%   r2   r;   r*   r<   Ztag_bufr+   r+   r,   finalize   sX    


z_CipherContext.finalizec                 C   s`   t || jjk r"td| jj| jj| j| jjj	t ||}| j
|dk || _|  S )Nz.Authentication tag must be {} bytes or longer.r   )r   r   Z_min_tag_lengthr6   r   r   r   r!   r$   r#   r   r   r@   )r%   r"   r*   r+   r+   r,   finalize_with_tag   s    z _CipherContext.finalize_with_tagc                 C   sN   | j jd}| j j| j| j jj|| j j|t|}| j 	|dk d S )Nr5   r   )
r   r   r7   r   r:   r$   r   r   r   r   )r%   r1   r;   r*   r+   r+   r,   authenticate_additional_data   s    z+_CipherContext.authenticate_additional_datar   N)__name__
__module____qualname__r>   r=   r9   r-   r4   r/   r@   rA   rB   r   Zread_only_propertyr"   r+   r+   r+   r,   r      s   d3r   N)Z
__future__r   r   r   Zcryptographyr   Zcryptography.exceptionsr   r   r   Zcryptography.hazmat.primitivesr	   Z&cryptography.hazmat.primitives.ciphersr
   Zregister_interfaceZCipherContextZAEADCipherContextZAEADEncryptionContextZAEADDecryptionContextobjectr   r+   r+   r+   r,   <module>   s   

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