Challenges

ACME Identifier Validation Challenges.

class acme.challenges.Challenge(**kwargs)[source]

Bases: josepy.json_util.TypedJSONObjectWithFields

ACME challenge.

classmethod from_json(jobj)[source]

Deserialize ACME object from valid JSON object.

Raises:josepy.errors.UnrecognizedTypeError – if type of the ACME object has not been registered.
class acme.challenges.ChallengeResponse(**kwargs)[source]

Bases: josepy.json_util.TypedJSONObjectWithFields

ACME challenge response.

class acme.challenges.UnrecognizedChallenge(jobj)[source]

Bases: acme.challenges.Challenge

Unrecognized challenge.

ACME specification defines a generic framework for challenges and defines some standard challenges that are implemented in this module. However, other implementations (including peers) might define additional challenge types, which should be ignored if unrecognized.

Variables:jobj – Original JSON decoded object.
to_partial_json()[source]

Get JSON serializable object.

Returns:Serializable JSON object representing ACME typed object. validate() will almost certainly not work, due to reasons explained in josepy.interfaces.IJSONSerializable.
Return type:dict
classmethod from_json(jobj)[source]

Deserialize ACME object from valid JSON object.

Raises:josepy.errors.UnrecognizedTypeError – if type of the ACME object has not been registered.
class acme.challenges._TokenChallenge(**kwargs)[source]

Bases: acme.challenges.Challenge

Challenge with token.

Variables:token (bytes) –
TOKEN_SIZE = 16

Minimum size of the token in bytes.

good_token

Is token good?

Todo

acme-spec wants “It MUST NOT contain any non-ASCII characters”, but it should also warrant that it doesn’t contain “..” or “/”…

class acme.challenges.KeyAuthorizationChallengeResponse(**kwargs)[source]

Bases: acme.challenges.ChallengeResponse

Response to Challenges based on Key Authorization.

Parameters:key_authorization (unicode) –
verify(chall, account_public_key)[source]

Verify the key authorization.

Parameters:
  • chall (KeyAuthorization) – Challenge that corresponds to this response.
  • account_public_key (JWK) –
Returns:

True iff verification of the key authorization was successful.
Return type:

bool
class acme.challenges.KeyAuthorizationChallenge(**kwargs)[source]

Bases: acme.challenges._TokenChallenge

Challenge based on Key Authorization.

Parameters:
key_authorization(account_key)[source]

Generate Key Authorization.

Parameters:account_key (JWK) –
Rtype unicode:
response(account_key)[source]

Generate response to the challenge.

Parameters:account_key (JWK) –
Returns:Response (initialized response_cls) to the challenge.
Return type:KeyAuthorizationChallengeResponse
validation(account_key, **kwargs)[source]

Generate validation for the challenge.

Subclasses must implement this method, but they are likely to return completely different data structures, depending on what’s necessary to complete the challenge. Interpretation of that return value must be known to the caller.

Parameters:account_key (JWK) –
Returns:Challenge-specific validation.
response_and_validation(account_key, *args, **kwargs)[source]

Generate response and validation.

Convenience function that return results of response and validation.

Parameters:account_key (JWK) –
Return type:tuple
class acme.challenges.DNS01Response(**kwargs)[source]

Bases: acme.challenges.KeyAuthorizationChallengeResponse

ACME dns-01 challenge response.

simple_verify(chall, domain, account_public_key)[source]

Simple verify.

This method no longer checks DNS records and is a simple wrapper around KeyAuthorizationChallengeResponse.verify.

Parameters:
  • chall (challenges.DNS01) – Corresponding challenge.
  • domain (unicode) – Domain name being verified.
  • account_public_key (JWK) – Public key for the key pair being authorized.
Returns:

True iff verification of the key authorization was successful.
Return type:

bool
class acme.challenges.DNS01(**kwargs)[source]

Bases: acme.challenges.KeyAuthorizationChallenge

ACME dns-01 challenge.

response_cls

alias of DNS01Response

LABEL = '_acme-challenge'

Label clients prepend to the domain name being validated.

validation(account_key, **unused_kwargs)[source]

Generate validation.

Parameters:account_key (JWK) –
Return type:unicode
validation_domain_name(name)[source]

Domain name for TXT validation record.

Parameters:name (unicode) – Domain name being validated.
class acme.challenges.HTTP01Response(**kwargs)[source]

Bases: acme.challenges.KeyAuthorizationChallengeResponse

ACME http-01 challenge response.

PORT = 80

Verification port as defined by the protocol.

You can override it (e.g. for testing) by passing port to simple_verify.

WHITESPACE_CUTSET = '\n\r\t '

Whitespace characters which should be ignored at the end of the body.

simple_verify(chall, domain, account_public_key, port=None)[source]

Simple verify.

Parameters:
  • chall (challenges.SimpleHTTP) – Corresponding challenge.
  • domain (unicode) – Domain name being verified.
  • account_public_key (JWK) – Public key for the key pair being authorized.
  • port (int) – Port used in the validation.
Returns:

True iff validation with the files currently served by the HTTP server is successful.
Return type:

bool
class acme.challenges.HTTP01(**kwargs)[source]

Bases: acme.challenges.KeyAuthorizationChallenge

ACME http-01 challenge.

response_cls

alias of HTTP01Response

URI_ROOT_PATH = '.well-known/acme-challenge'

URI root path for the server provisioned resource.

path

Path (starting with ‘/’) for provisioned resource.

Return type:string
uri(domain)[source]

Create an URI to the provisioned resource.

Forms an URI to the HTTPS server provisioned resource (containing token).

Parameters:domain (unicode) – Domain name being verified.
Return type:string
validation(account_key, **unused_kwargs)[source]

Generate validation.

Parameters:account_key (JWK) –
Return type:unicode
class acme.challenges.TLSSNI01Response(**kwargs)[source]

Bases: acme.challenges.KeyAuthorizationChallengeResponse

ACME tls-sni-01 challenge response.

DOMAIN_SUFFIX = '.acme.invalid'

Domain name suffix.

PORT = 443

Verification port as defined by the protocol.

You can override it (e.g. for testing) by passing port to simple_verify.

z

z value used for verification.

Rtype bytes:
z_domain

Domain name used for verification, generated from z.

Rtype bytes:
gen_cert(key=None, bits=2048)[source]

Generate tls-sni-01 certificate.

Parameters:
  • key (OpenSSL.crypto.PKey) – Optional private key used in certificate generation. If not provided (None), then fresh key will be generated.
  • bits (int) – Number of bits for newly generated key.
Return type:

tuple of OpenSSL.crypto.X509 and OpenSSL.crypto.PKey
probe_cert(domain, **kwargs)[source]

Probe tls-sni-01 challenge certificate.

Parameters:domain (unicode) –
verify_cert(cert)[source]

Verify tls-sni-01 challenge certificate.

Parameters:cert (OpensSSL.crypto.X509) – Challenge certificate.
Returns:Whether the certificate was successfully verified.
Return type:bool
simple_verify(chall, domain, account_public_key, cert=None, **kwargs)[source]

Simple verify.

Verify validation using account_public_key, optionally probe tls-sni-01 certificate and check using verify_cert.

Parameters:
  • chall (challenges.TLSSNI01) – Corresponding challenge.
  • domain (str) – Domain name being validated.
  • account_public_key (JWK) –
  • cert (OpenSSL.crypto.X509) – Optional certificate. If not provided (None) certificate will be retrieved using probe_cert.
  • port (int) – Port used to probe the certificate.
Returns:

True iff client’s control of the domain has been verified.
Return type:

bool
class acme.challenges.TLSSNI01(*args, **kwargs)[source]

Bases: acme.challenges.KeyAuthorizationChallenge

ACME tls-sni-01 challenge.

response_cls

alias of TLSSNI01Response

validation(account_key, **kwargs)[source]

Generate validation.

Parameters:
  • account_key (JWK) –
  • cert_key (OpenSSL.crypto.PKey) – Optional private key used in certificate generation. If not provided (None), then fresh key will be generated.
Return type:

tuple of OpenSSL.crypto.X509 and OpenSSL.crypto.PKey
class acme.challenges.TLSALPN01Response(**kwargs)[source]

Bases: acme.challenges.KeyAuthorizationChallengeResponse

ACME TLS-ALPN-01 challenge response.

This class only allows initiating a TLS-ALPN-01 challenge returned from the CA. Full support for responding to TLS-ALPN-01 challenges by generating and serving the expected response certificate is not currently provided.

class acme.challenges.TLSALPN01(**kwargs)[source]

Bases: acme.challenges.KeyAuthorizationChallenge

ACME tls-alpn-01 challenge.

This class simply allows parsing the TLS-ALPN-01 challenge returned from the CA. Full TLS-ALPN-01 support is not currently provided.

response_cls

alias of TLSALPN01Response

validation(account_key, **kwargs)[source]

Generate validation for the challenge.

class acme.challenges.DNS(**kwargs)[source]

Bases: acme.challenges._TokenChallenge

ACME “dns” challenge.

LABEL = '_acme-challenge'

Label clients prepend to the domain name being validated.

gen_validation(account_key, alg=RS256, **kwargs)[source]

Generate validation.

Parameters:
  • account_key (JWK) – Private account key.
  • alg (JWA) –
Returns:

This challenge wrapped in JWS
Return type:

JWS
check_validation(validation, account_public_key)[source]

Check validation.

Parameters:
  • validation (JWS) –
  • account_public_key (JWK) –
Return type:

bool
gen_response(account_key, **kwargs)[source]

Generate response.

Parameters:
  • account_key (JWK) – Private account key.
  • alg (JWA) –
Return type:

DNSResponse
validation_domain_name(name)[source]

Domain name for TXT validation record.

Parameters:name (unicode) – Domain name being validated.
class acme.challenges.DNSResponse(**kwargs)[source]

Bases: acme.challenges.ChallengeResponse

ACME “dns” challenge response.

Parameters:validation (JWS) –
check_validation(chall, account_public_key)[source]

Check validation.

Parameters:
Return type:

bool