3
¥K´^4	  ã               @   sH   d dl mZmZmZ d dlmZ d dlmZ dZdZ	G dd„ de
ƒZdS )	é    )Úabsolute_importÚdivisionÚprint_function)ÚInvalidSignature)Úconstant_timeé   é    c               @   s,   e Zd Zdd„ Zdd„ Zdd„ Zdd„ Zd	S )
Ú_Poly1305Contextc             C   sà   || _ | j jj|ƒ}| j jj| j jj| j jj|t|ƒƒ}| j j|| j jjkƒ | j jj	|| j jj
ƒ| _| j jjƒ }| j j|| j jjkƒ | j jj	|| j jjƒ| _| j jj| j| j jj| j jj| j jj| jƒ}| j j|dkƒ d S )Né   )Ú_backendÚ_ffiÚfrom_bufferÚ_libZEVP_PKEY_new_raw_private_keyZNID_poly1305ZNULLÚlenÚopenssl_assertÚgcZEVP_PKEY_freeZ	_evp_pkeyZCryptography_EVP_MD_CTX_newZCryptography_EVP_MD_CTX_freeÚ_ctxZEVP_DigestSignInit)ÚselfÚbackendÚkeyZkey_ptrZevp_pkeyÚctxÚres© r   úQ/tmp/pip-unpacked-wheel-vvkwn1hz/cryptography/hazmat/backends/openssl/poly1305.pyÚ__init__   s     z_Poly1305Context.__init__c             C   s:   | j jj|ƒ}| j jj| j|t|ƒƒ}| j j|dkƒ d S )Nr   )r   r   r   r   ZEVP_DigestSignUpdater   r   r   )r   ÚdataZdata_ptrr   r   r   r   Úupdate*   s    z_Poly1305Context.updatec             C   sp   | j jjdtƒ}| j jjdƒ}| j jj| j||ƒ}| j j|dkƒ | j j|d tkƒ | j jj|ƒd |d … S )Nzunsigned char[]zsize_t *r   )	r   r   ÚnewÚ_POLY1305_TAG_SIZEr   ZEVP_DigestSignFinalr   r   Úbuffer)r   ÚbufZoutlenr   r   r   r   Úfinalize1   s    z_Poly1305Context.finalizec             C   s    | j ƒ }tj||ƒstdƒ‚d S )Nz!Value did not match computed tag.)r!   r   Zbytes_eqr   )r   ÚtagÚmacr   r   r   Úverify9   s    z_Poly1305Context.verifyN)Ú__name__Ú
__module__Ú__qualname__r   r   r!   r$   r   r   r   r   r	      s   r	   N)Ú
__future__r   r   r   Zcryptography.exceptionsr   Zcryptography.hazmat.primitivesr   r   Z_POLY1305_KEY_SIZEÚobjectr	   r   r   r   r   Ú<module>   s
   