google.auth.crypt package¶

Cryptography helpers for verifying and signing messages.

The simplest way to verify signatures is using verify_signature():

cert = open('certs.pem').read()
valid = crypt.verify_signature(message, signature, cert)

If you’re going to verify many messages with the same certificate, you can use RSAVerifier:

cert = open('certs.pem').read()
verifier = crypt.RSAVerifier.from_string(cert)
valid = verifier.verify(message, signature)

To sign messages use RSASigner with a private key:

private_key = open('private_key.pem').read()
signer = crypt.RSASigner.from_string(private_key)
signature = signer.sign(message)

The code above also works for ES256Signer and ES256Verifier. Note that these two classes are only available if your cryptography dependency version is at least 1.4.0.

class RSASigner(private_key, key_id=None)[source]¶

Bases: Signer, FromServiceAccountMixin

Signs messages with an RSA private key.

Parameters:

private_key (rsa.key.PrivateKey) – The private key to sign with.
key_id (str) – Optional key ID used to identify this private key. This can be useful to associate the private key with its associated public key or certificate.

property key_id¶

The key ID used to identify this private key.

Type:: Optional [ str ]

sign(message)[source]¶

Signs a message.

Parameters:: message (Union [ str, bytes ]) – The message to be signed.
Returns:: The signature of the message.
Return type:: bytes

classmethod from_string(key, key_id=None)[source]¶

Construct an Signer instance from a private key in PEM format.

Parameters:

key (str) – Private key in PEM format.
key_id (str) – An optional key id used to identify the private key.

Returns:

The constructed signer.

Return type:

google.auth.crypt.Signer

Raises:

ValueError – If the key cannot be parsed as PKCS#1 or PKCS#8 in PEM format.

classmethod from_service_account_file(filename)¶

Creates a Signer instance from a service account .json file in Google format.

Parameters:: filename (str) – The path to the service account .json file.
Returns:: The constructed signer.
Return type:: google.auth.crypt.Signer

classmethod from_service_account_info(info)¶

Creates a Signer instance instance from a dictionary containing service account info in Google format.

Parameters:: info (Mapping [ str, str ]) – The service account info in Google format.
Returns:: The constructed signer.
Return type:: google.auth.crypt.Signer
Raises:: ValueError – If the info is not in the expected format.

class RSAVerifier(public_key)[source]¶

Bases: Verifier

Verifies RSA cryptographic signatures using public keys.

Parameters:: public_key (rsa.key.PublicKey) – The public key used to verify signatures.

verify(message, signature)[source]¶

Verifies a message against a cryptographic signature.

Parameters:

message (Union [ str, bytes ]) – The message to verify.
signature (Union [ str, bytes ]) – The cryptography signature to check.

Returns:

True if message was signed by the private key associated with the public key that this object was constructed with.

Return type:

bool

classmethod from_string(public_key)[source]¶

Construct an Verifier instance from a public key or public certificate string.

Parameters:: public_key (Union [ str, bytes ]) – The public key in PEM format or the x509 public key certificate.
Returns:: The constructed verifier.
Return type:: google.auth.crypt._python_rsa.RSAVerifier
Raises:: ValueError – If the public_key can’t be parsed.

class Signer[source]¶

Bases: object

Abstract base class for cryptographic signers.

abstract property key_id¶

The key ID used to identify this private key.

Type:: Optional [ str ]

abstract sign(message)[source]¶

Signs a message.

Parameters:: message (Union [ str, bytes ]) – The message to be signed.
Returns:: The signature of the message.
Return type:: bytes