3
K^                 @   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j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j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jjk | jjj|| jjj}| jj	|}|| jjjkrzt
dj|jtj| jjj|}| jjj||t||| j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-vvkwn1hz/cryptography/hazmat/backends/openssl/hmac.py__init__   s&    z_HMACContext.__init__r   c             C   sp   | j jj }| j j|| j jjk | j jj|| 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"   copy-   s    z_HMACContext.copyc             C   s:   | j jj|}| j jj| j|t|}| j j|dk d S )Nr   )r   r   r   r   ZHMAC_Updater   r   r   )r   dataZdata_ptrr    r!   r!   r"   update9   s    z_HMACContext.updatec             C   sz   | j jjd| j jj}| j jjd}| j jj| j||}| j j|dk | j j|d | jj	k | j 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"   finalize>   s    
z_HMACContext.finalizec             C   s    | j  }tj||stdd S )NzSignature did not match digest.)r+   r	   Zbytes_eqr   )r   	signaturedigestr!   r!   r"   verifyG   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
   