diff options
Diffstat (limited to 'docs/hazmat/primitives/asymmetric/dsa.rst')
| -rw-r--r-- | docs/hazmat/primitives/asymmetric/dsa.rst | 101 |
1 files changed, 96 insertions, 5 deletions
diff --git a/docs/hazmat/primitives/asymmetric/dsa.rst b/docs/hazmat/primitives/asymmetric/dsa.rst index 2819bbdb..6848d84c 100644 --- a/docs/hazmat/primitives/asymmetric/dsa.rst +++ b/docs/hazmat/primitives/asymmetric/dsa.rst @@ -38,11 +38,11 @@ DSA Generate a new ``DSAParameters`` instance using ``backend``. :param int key_size: The length of the modulus in bits. It should be - either "1024, 2048 or 3072". For keys generated in 2014 this should - be `at least 2048`_ (See page 41). - Note that some applications (such as SSH) have not yet gained support - for larger key sizes specified in FIPS 186-3 and are still restricted - to only the 1024-bit keys specified in FIPS 186-2. + either 1024, 2048 or 3072. For keys generated in 2014 this should + be `at least 2048`_ (See page 41). Note that some applications + (such as SSH) have not yet gained support for larger key sizes + specified in FIPS 186-3 and are still restricted to only the + 1024-bit keys specified in FIPS 186-2. :return: A new instance of ``DSAParameters`` @@ -97,6 +97,48 @@ DSA or if the OpenSSL version is older than 1.0.0 and the key size is larger than 1024 because older OpenSSL versions don't support a key size larger than 1024. + .. method:: signer(algorithm, backend) + + .. versionadded:: 0.4 + + Sign data which can be verified later by others using the public key. + + .. doctest:: + + >>> from cryptography.hazmat.backends import default_backend + >>> from cryptography.hazmat.primitives import hashes + >>> from cryptography.hazmat.primitives.asymmetric import dsa + >>> parameters = dsa.DSAParameters.generate( + ... key_size=1024, + ... backend=default_backend() + ... ) + >>> private_key = dsa.DSAPrivateKey.generate( + ... parameters=parameters, + ... backend=default_backend() + ... ) + >>> signer = private_key.signer( + ... hashes.SHA256(), + ... default_backend() + ... ) + >>> data = b"this is some data I'd like to sign" + >>> signer.update(data) + >>> signature = signer.finalize() + + :param algorithm: An instance of a + :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm` + provider. + + :param backend: A + :class:`~cryptography.hazmat.backends.interfaces.RSABackend` + provider. + + :returns: + :class:`~cryptography.hazmat.primitives.interfaces.AsymmetricSignatureContext` + + :raises cryptography.exceptions.UnsupportedAlgorithm: This is raised if + the provided ``backend`` does not implement + :class:`~cryptography.hazmat.backends.interfaces.DSABackend` + .. class:: DSAPublicKey(modulus, subgroup_order, generator, y) @@ -118,6 +160,55 @@ DSA ``subgroup_order``, ``generator``, or ``y`` do not match the bounds specified in `FIPS 186-4`_. + .. method:: verifier(signature, algorithm, backend) + + .. versionadded:: 0.4 + + Verify data was signed by the private key associated with this public + key. + + .. doctest:: + + >>> from cryptography.hazmat.backends import default_backend + >>> from cryptography.hazmat.primitives import hashes + >>> from cryptography.hazmat.primitives.asymmetric import dsa + >>> parameters = dsa.DSAParameters.generate( + ... key_size=1024, + ... backend=default_backend() + ... ) + >>> private_key = dsa.DSAPrivateKey.generate( + ... parameters=parameters, + ... backend=default_backend() + ... ) + >>> signer = private_key.signer( + ... hashes.SHA256(), + ... default_backend() + ... ) + >>> data = b"this is some data I'd like to sign" + >>> signer.update(data) + >>> signature = signer.finalize() + >>> public_key = private_key.public_key() + >>> verifier = public_key.verifier( + ... signature, + ... hashes.SHA256(), + ... default_backend() + ... ) + >>> verifier.update(data) + >>> verifier.verify() + + :param bytes signature: The signature to verify. DER encoded as + specified in :rfc:`6979`. + + :param algorithm: An instance of a + :class:`~cryptography.hazmat.primitives.interfaces.HashAlgorithm` + provider. + + :param backend: A + :class:`~cryptography.hazmat.backends.interfaces.DSABackend` + provider. + + :returns: + :class:`~cryptography.hazmat.primitives.interfaces.AsymmetricVerificationContext` .. _`DSA`: https://en.wikipedia.org/wiki/Digital_Signature_Algorithm .. _`public-key`: https://en.wikipedia.org/wiki/Public-key_cryptography |