The golden rule of web application security is to never trust data from\nuntrusted sources. Sometimes it can be useful to pass data through an\nuntrusted medium. Cryptographically signed values can be passed through an\nuntrusted channel safe in the knowledge that any tampering will be detected.
\nDjango provides both a low-level API for signing values and a high-level API\nfor setting and reading signed cookies, one of the most common uses of\nsigning in web applications.
\nVocê também pode achar a assinatura útil para o seguinte:
\nGerar URLs do tipo “recuperar minha conta” para enviar a usuários que perderam suas senhas.
Garantir que dados armazenados em campos hidden de formulários não foram alterados.
Gerar URLs secretas de uso único para permitir acesso temporário a recursos protegidos, por exemplo um arquivo baixável pelo qual um usuário pagou.
SECRET_KEY and SECRET_KEY_FALLBACKSLink para este cabeçalho#Quando você cria um novo projeto Django usando startproject, o arquivo settings.py é gerado automaticamente e recebe um valor aleatório para a SECRET_KEY. Esse valor é a chave para proteger dados assinados – Ela é vital para manter isso seguro, ou atacantes podem usá-la para gerar seus próprios valores assinados.
SECRET_KEY_FALLBACKS can be used to rotate secret keys. The\nvalues will not be used to sign data, but if specified, they will be used to\nvalidate signed data and must be kept secure.
Django’s signing methods live in the django.core.signing module.\nTo sign a value, first instantiate a Signer instance:
>>> from django.core.signing import Signer\n>>> signer = Signer()\n>>> value = signer.sign("My string")\n>>> value\n'My string:GdMGD6HNQ_qdgxYP8yBZAdAIV1w'\nThe signature is appended to the end of the string, following the colon.\nYou can retrieve the original value using the unsign method:
>>> original = signer.unsign(value)\n>>> original\n'My string'\nIf you pass a non-string value to sign, the value will be forced to string\nbefore being signed, and the unsign result will give you that string\nvalue:
>>> signed = signer.sign(2.5)\n>>> original = signer.unsign(signed)\n>>> original\n'2.5'\nIf you wish to protect a list, tuple, or dictionary you can do so using the\nsign_object() and unsign_object() methods:
>>> signed_obj = signer.sign_object({"message": "Hello!"})\n>>> signed_obj\n'eyJtZXNzYWdlIjoiSGVsbG8hIn0:Xdc-mOFDjs22KsQAqfVfi8PQSPdo3ckWJxPWwQOFhR4'\n>>> obj = signer.unsign_object(signed_obj)\n>>> obj\n{'message': 'Hello!'}\nSee Protegendo estruturas de dados complexas for more details.
\nIf the signature or value have been altered in any way, a\ndjango.core.signing.BadSignature exception will be raised:
>>> from django.core import signing\n>>> value += "m"\n>>> try:\n... original = signer.unsign(value)\n... except signing.BadSignature:\n... print("Tampering detected!")\n...\nBy default, the Signer class uses the SECRET_KEY setting to\ngenerate signatures. You can use a different secret by passing it to the\nSigner constructor:
>>> signer = Signer(key="my-other-secret")\n>>> value = signer.sign("My string")\n>>> value\n'My string:EkfQJafvGyiofrdGnuthdxImIJw'\nReturns a signer which uses key to generate signatures and sep to\nseparate values. sep cannot be in the URL safe base64 alphabet. This alphabet contains alphanumeric characters, hyphens,\nand underscores. algorithm must be an algorithm supported by\nhashlib, it defaults to 'sha256'. fallback_keys is a list\nof additional values used to validate signed data, defaults to\nSECRET_KEY_FALLBACKS.
saltLink para este cabeçalho#If you do not wish for every occurrence of a particular string to have the same\nsignature hash, you can use the optional salt argument to the Signer\nclass. Using a salt will seed the signing hash function with both the salt and\nyour SECRET_KEY:
>>> signer = Signer()\n>>> signer.sign("My string")\n'My string:GdMGD6HNQ_qdgxYP8yBZAdAIV1w'\n>>> signer.sign_object({"message": "Hello!"})\n'eyJtZXNzYWdlIjoiSGVsbG8hIn0:Xdc-mOFDjs22KsQAqfVfi8PQSPdo3ckWJxPWwQOFhR4'\n>>> signer = Signer(salt="extra")\n>>> signer.sign("My string")\n'My string:Ee7vGi-ING6n02gkcJ-QLHg6vFw'\n>>> signer.unsign("My string:Ee7vGi-ING6n02gkcJ-QLHg6vFw")\n'My string'\n>>> signer.sign_object({"message": "Hello!"})\n'eyJtZXNzYWdlIjoiSGVsbG8hIn0:-UWSLCE-oUAHzhkHviYz3SOZYBjFKllEOyVZNuUtM-I'\n>>> signer.unsign_object(\n... "eyJtZXNzYWdlIjoiSGVsbG8hIn0:-UWSLCE-oUAHzhkHviYz3SOZYBjFKllEOyVZNuUtM-I"\n... )\n{'message': 'Hello!'}\nUtilizar o argumento salt dessa forma coloca as diferentes assinaturas em diferentes namespaces. A assinatura proveniente de um namespace (um valor para o argumento salt em particular) não pode ser usada para validar a mesma string em texto simples em um namespace diferente usando um valor de salt diferente. Esse resutado é para prevenir um invasor de usar a string gerada e assinada em um local no código como entrada para outro pedaço de código que está gerando (e verificando) assinaturas usando um valor diferente para o argumento salt.
\nAo contrário de sua SECRET_KEY, o seu argumento salt não precisa ser mantido em segredo.
TimestampSigner is a subclass of Signer that appends a signed\ntimestamp to the value. This allows you to confirm that a signed value was\ncreated within a specified period of time:
>>> from datetime import timedelta\n>>> from django.core.signing import TimestampSigner\n>>> signer = TimestampSigner()\n>>> value = signer.sign("hello")\n>>> value\n'hello:1NMg5H:oPVuCqlJWmChm1rA2lyTUtelC-c'\n>>> signer.unsign(value)\n'hello'\n>>> signer.unsign(value, max_age=10)\nSignatureExpired: Signature age 15.5289158821 > 10 seconds\n>>> signer.unsign(value, max_age=20)\n'hello'\n>>> signer.unsign(value, max_age=timedelta(seconds=20))\n'hello'\nAssina um value e adiciona um rótulo com o horário atual nele.
Verifica se o valor foi assinado a menos de max_age segundos atrás, caso contrário lança SignatureExpired. O parâmetro max_age pode aceitar um inteiro ou um objeto da classe datetime.timedelta.
Encode, optionally compress, append current timestamp, and sign complex\ndata structure (e.g. list, tuple, or dictionary).
\nChecks if signed_obj was signed less than max_age seconds ago,\notherwise raises SignatureExpired. The max_age parameter can\naccept an integer or a datetime.timedelta object.
If you wish to protect a list, tuple or dictionary you can do so using the\nSigner.sign_object() and unsign_object() methods, or signing module’s\ndumps() or loads() functions (which are shortcuts for\nTimestampSigner(salt='django.core.signing').sign_object()/unsign_object()).\nThese use JSON serialization under the hood. JSON ensures that even if your\nSECRET_KEY is stolen an attacker will not be able to execute\narbitrary commands by exploiting the pickle format:
>>> from django.core import signing\n>>> signer = signing.TimestampSigner()\n>>> value = signer.sign_object({"foo": "bar"})\n>>> value\n'eyJmb28iOiJiYXIifQ:1kx6R3:D4qGKiptAqo5QW9iv4eNLc6xl4RwiFfes6oOcYhkYnc'\n>>> signer.unsign_object(value)\n{'foo': 'bar'}\n>>> value = signing.dumps({"foo": "bar"})\n>>> value\n'eyJmb28iOiJiYXIifQ:1kx6Rf:LBB39RQmME-SRvilheUe5EmPYRbuDBgQp2tCAi7KGLk'\n>>> signing.loads(value)\n{'foo': 'bar'}\nBecause of the nature of JSON (there is no native distinction between lists\nand tuples) if you pass in a tuple, you will get a list from\nsigning.loads(object):
>>> from django.core import signing\n>>> value = signing.dumps(("a", "b", "c"))\n>>> signing.loads(value)\n['a', 'b', 'c']\nReturns URL-safe, signed base64 compressed JSON string. Serialized object\nis signed using TimestampSigner.
Inverso da função dumps(), lança BadSignature se a assinatura falhar. Verifica o max_age (em segundos) se fornecido.