Module « Crypto.Signature.PKCS1_v1_5 »

Fonction EMSA_PKCS1_V1_5_ENCODE - module Crypto.Signature.PKCS1_v1_5

Signature de la fonction EMSA_PKCS1_V1_5_ENCODE

def EMSA_PKCS1_V1_5_ENCODE(hash, emLen) 

Description

EMSA_PKCS1_V1_5_ENCODE.__doc__

    Implement the ``EMSA-PKCS1-V1_5-ENCODE`` function, as defined
    in PKCS#1 v2.1 (RFC3447, 9.2).

    ``EMSA-PKCS1-V1_5-ENCODE`` actually accepts the message ``M`` as input,
    and hash it internally. Here, we expect that the message has already
    been hashed instead.

    :Parameters:
     hash : hash object
            The hash object that holds the digest of the message being signed.
     emLen : int
            The length the final encoding must have, in bytes.

    :attention: the early standard (RFC2313) stated that ``DigestInfo``
        had to be BER-encoded. This means that old signatures
        might have length tags in indefinite form, which
        is not supported in DER. Such encoding cannot be
        reproduced by this function.

    :attention: the same standard defined ``DigestAlgorithm`` to be
        of ``AlgorithmIdentifier`` type, where the PARAMETERS
        item is optional. Encodings for ``MD2/4/5`` without
        ``PARAMETERS`` cannot be reproduced by this function.

    :Return: An ``emLen`` byte long string that encodes the hash.