U
    *}f                     @   sd   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mZ eejG dd deZdS )    )absolute_importdivisionprint_function)utils)InvalidSignatureUnsupportedAlgorithm_Reasons)constant_timehashesc                   @   s@   e Zd ZdddZedZdd Zdd Zd	d
 Z	dd Z
dS )_HMACContextNc                 C   s   || _ || _|d kr| jj }| j|| jjjk | jj|| jjj}| j	|}|| jjjkrzt
d|jtj| jj|}| jj||t||| jjj}| j|dk || _|| _d S )Nz*{} is not a supported hash on this backendr   )
_algorithm_backend_libCryptography_HMAC_CTX_newopenssl_assert_ffiNULLgcCryptography_HMAC_CTX_freeZ_evp_md_from_algorithmr   formatnamer   ZUNSUPPORTED_HASHfrom_bufferZHMAC_Init_exlen_ctx_key)selfbackendkey	algorithmctxZevp_mdZkey_ptrres r!   M/tmp/pip-unpacked-wheel-x36vw73o/cryptography/hazmat/backends/openssl/hmac.py__init__   s8         z_HMACContext.__init__r   c                 C   sp   | j j }| j || j jjk | j j|| j jj}| j j|| j	}| j |dk t
| j | j| j|dS )Nr   )r   )r   r   r   r   r   r   r   r   ZHMAC_CTX_copyr   r   r   r   )r   Z
copied_ctxr    r!   r!   r"   copy0   s        z_HMACContext.copyc                 C   s:   | j j|}| j j| j|t|}| j |dk d S )Nr   )r   r   r   r   ZHMAC_Updater   r   r   )r   dataZdata_ptrr    r!   r!   r"   update<   s    z_HMACContext.updatec                 C   sz   | j jd| j jj}| j jd}| j j| j||}| j |dk | j |d | jj	k | j j
|d |d  S )Nzunsigned char[]zunsigned int *r   )r   r   newr   ZEVP_MAX_MD_SIZEZ
HMAC_Finalr   r   r   digest_sizebuffer)r   bufZoutlenr    r!   r!   r"   finalizeA   s     z_HMACContext.finalizec                 C   s    |   }t||stdd S )NzSignature did not match digest.)r+   r	   Zbytes_eqr   )r   	signaturedigestr!   r!   r"   verifyK   s    z_HMACContext.verify)N)__name__
__module____qualname__r#   r   Zread_only_propertyr   r$   r&   r+   r.   r!   r!   r!   r"   r      s   


r   N)
__future__r   r   r   Zcryptographyr   Zcryptography.exceptionsr   r   r   Zcryptography.hazmat.primitivesr	   r
   Zregister_interfaceZHashContextobjectr   r!   r!   r!   r"   <module>   s
   
