def get_signature(signature_data):
    try:
        signature = base64.decode_as_bytes(signature_data)
    except (TypeError, binascii.Error):
        raise exception.SignatureVerificationError(
            reason=_('The signature data was not properly '
                     'encoded using base64'))

    return signature
Compute the standard deviation of the histogram
dataset/ETHPy150Open BU-NU-CLOUD-SP16/Trusted-Platform-Module-nova/nova/signature_utils.py/get_signature--crossover with--dataset/ETHPy150Open neurodata/ndstore/scripts/imghist16.py/ImgHist.stddev