# Module: `nbformat.sign`

Functions for signing notebooks

## 2 Classes

class `IPython.nbformat.sign.``NotebookNotary`(**kwargs)

  Bases: `IPython.config.configurable.LoggingConfigurable`

  A class for computing and verifying notebook signatures.

  `check_cells`(nb)

    Return whether all code cells are trusted

    If there are no code cells, return True.

    This function is the inverse of mark_cells.

  `check_signature`(nb)

    Check a notebook’s stored signature

    If a signature is stored in the notebook’s metadata, a new signature is computed and compared with the stored value.

    Returns True if the signature is found and matches, False otherwise.

    The following conditions must all be met for a notebook to be trusted: - a signature is stored in the form ‘scheme:hexdigest’ - the stored scheme matches the requested scheme - the requested scheme is available from hashlib - the computed hash from notebook_signature matches the stored hash

  `compute_signature`(nb)

    Compute a notebook’s signature

    by hashing the entire contents of the notebook via HMAC digest.

  `mark_cells`(nb, trusted)

    Mark cells as trusted if the notebook’s signature can be verified

    Sets `cell.trusted = True | False` on all code cells, depending on whether the stored signature can be verified.

    This function is the inverse of check_cells

  `sign`(nb)

    Sign a notebook, indicating that its output is trusted

    stores ‘algo:hmac-hexdigest’ in notebook.metadata.signature

    e.g. ‘sha256:deadbeef123...’

class `IPython.nbformat.sign.``TrustNotebookApp`(**kwargs)

  Bases: `IPython.core.application.BaseIPythonApplication`

  `generate_new_key`()

    Generate a new notebook signature key

## 2 Functions

`IPython.nbformat.sign.``yield_everything`(obj)

  Yield every item in a container as bytes

  Allows any JSONable object to be passed to an HMAC digester without having to serialize the whole thing.

`IPython.nbformat.sign.``signature_removed`(*args, **kwds)

  Context manager for operating on a notebook with its signature removed

  Used for excluding the previous signature when computing a notebook’s signature.