diff options
Diffstat (limited to 'docs/hazmat')
| -rw-r--r-- | docs/hazmat/primitives/hmac.rst | 32 | ||||
| -rw-r--r-- | docs/hazmat/primitives/symmetric-encryption.rst | 16 |
2 files changed, 35 insertions, 13 deletions
diff --git a/docs/hazmat/primitives/hmac.rst b/docs/hazmat/primitives/hmac.rst index dc5c54f8..a21799be 100644 --- a/docs/hazmat/primitives/hmac.rst +++ b/docs/hazmat/primitives/hmac.rst @@ -37,6 +37,16 @@ message. If the backend doesn't support the requested ``algorithm`` an :class:`~cryptography.exceptions.UnsupportedAlgorithm` will be raised. + To check that a given signature is correct use the :meth:`verify` method. + You will receive an exception if the signature is wrong: + + .. code-block:: pycon + + >>> h.verify(b"an incorrect signature") + Traceback (most recent call last): + ... + cryptography.exceptions.InvalidSignature: Signature did not match digest. + :param key: Secret key as ``bytes``. :param algorithm: A :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm` @@ -61,17 +71,6 @@ message. and finalized independently of the original instance. :raises cryptography.exceptions.AlreadyFinalized: See :meth:`finalize` - .. method:: finalize() - - Finalize the current context and return the message digest as bytes. - - Once ``finalize`` is called this object can no longer be used and - :meth:`update`, :meth:`copy`, and :meth:`finalize` will raise - :class:`~cryptography.exceptions.AlreadyFinalized`. - - :return bytes: The message digest as bytes. - :raises cryptography.exceptions.AlreadyFinalized: - .. method:: verify(signature) Finalize the current context and securely compare digest to @@ -82,3 +81,14 @@ message. :raises cryptography.exceptions.AlreadyFinalized: See :meth:`finalize` :raises cryptography.exceptions.InvalidSignature: If signature does not match digest + + .. method:: finalize() + + Finalize the current context and return the message digest as bytes. + + Once ``finalize`` is called this object can no longer be used and + :meth:`update`, :meth:`copy`, and :meth:`finalize` will raise + :class:`~cryptography.exceptions.AlreadyFinalized`. + + :return bytes: The message digest as bytes. + :raises cryptography.exceptions.AlreadyFinalized: diff --git a/docs/hazmat/primitives/symmetric-encryption.rst b/docs/hazmat/primitives/symmetric-encryption.rst index 2233d525..83165690 100644 --- a/docs/hazmat/primitives/symmetric-encryption.rst +++ b/docs/hazmat/primitives/symmetric-encryption.rst @@ -169,6 +169,8 @@ Modes CBC (Cipher block chaining) is a mode of operation for block ciphers. It is considered cryptographically strong. + **Padding is required when using this mode.** + :param bytes initialization_vector: Must be random bytes. They do not need to be kept secret (they can be included in a transmitted message). Must be the @@ -211,6 +213,8 @@ Modes cryptographically strong. It transforms a block cipher into a stream cipher. + **This mode does not require padding.** + :param bytes nonce: Should be random bytes. It is critical to never reuse a ``nonce`` with a given key. Any reuse of a nonce with the same key compromises the security of every @@ -224,6 +228,8 @@ Modes OFB (Output Feedback) is a mode of operation for block ciphers. It transforms a block cipher into a stream cipher. + **This mode does not require padding.** + :param bytes initialization_vector: Must be random bytes. They do not need to be kept secret (they can be included in a transmitted message). Must be the @@ -237,6 +243,8 @@ Modes CFB (Cipher Feedback) is a mode of operation for block ciphers. It transforms a block cipher into a stream cipher. + **This mode does not require padding.** + :param bytes initialization_vector: Must be random bytes. They do not need to be kept secret (they can be included in a transmitted message). Must be the @@ -261,6 +269,8 @@ Modes Additional means of verifying integrity (like :doc:`HMAC </hazmat/primitives/hmac>`) are not necessary. + **This mode does not require padding.** + :param bytes initialization_vector: Must be random bytes. They do not need to be kept secret (they can be included in a transmitted message). NIST @@ -365,6 +375,8 @@ Insecure Modes identical plaintext blocks will always result in identical ciphertext blocks, and thus result in information leakage + **Padding is required when using this mode.** + Interfaces ---------- @@ -377,8 +389,8 @@ Interfaces finish the operation and obtain the remainder of the data. Block ciphers require that plaintext or ciphertext always be a multiple of - their block size, because of that **padding** is often required to make a - message the correct size. ``CipherContext`` will not automatically apply + their block size, because of that **padding** is sometimes required to make + a message the correct size. ``CipherContext`` will not automatically apply any padding; you'll need to add your own. For block ciphers the recommended padding is :class:`cryptography.hazmat.primitives.padding.PKCS7`. If you are using a stream cipher mode (such as |