A Python implementation of Sign-In with Ethereum (EIP-4361).
Project description
Sign-In with Ethereum
This package provides a Python implementation of EIP-4361: Sign In With Ethereum.
Installation
SIWE can be easily installed in any Python project with pip:
pip install siwe
Usage
SIWE provides a SiweMessage
class which implements EIP-4361.
Parsing a SIWE Message
Parsing is done by initializing a SiweMessage
object with an EIP-4361 formatted string:
from siwe import SiweMessage
message = SiweMessage.from_message(message=eip_4361_string)
Or to initialize a SiweMessage
as a pydantic.BaseModel
right away:
message = SiweMessage(domain="login.xyz", address="0x1234...", ...)
Verifying and Authenticating a SIWE Message
Verification and authentication is performed via EIP-191, using the address
field of the SiweMessage
as the expected signer. The validate method checks message structural integrity, signature address validity, and time-based validity attributes.
try:
message.verify(signature="0x...")
# You can also specify other checks (e.g. the nonce or domain expected).
except siwe.ValidationError:
# Invalid
Serialization of a SIWE Message
SiweMessage
instances can also be serialized as their EIP-4361 string representations via the prepare_message
method:
print(message.prepare_message())
Example
Parsing and verifying a SiweMessage
is easy:
try:
message: SiweMessage = SiweMessage(message=eip_4361_string)
message.verify(signature, nonce="abcdef", domain="example.com"):
except siwe.ValueError:
# Invalid message
print("Authentication attempt rejected.")
except siwe.ExpiredMessage:
print("Authentication attempt rejected.")
except siwe.DomainMismatch:
print("Authentication attempt rejected.")
except siwe.NonceMismatch:
print("Authentication attempt rejected.")
except siwe.MalformedSession as e:
# e.missing_fields contains the missing information needed for validation
print("Authentication attempt rejected.")
except siwe.InvalidSignature:
print("Authentication attempt rejected.")
# Message has been verified. Authentication complete. Continue with authorization/other.
Testing
poetry install
git submodule update --init
poetry run pytest
See Also
- Sign-In with Ethereum: TypeScript
- Example SIWE application: login.xyz
- EIP-4361 Specification Draft
- EIP-191 Specification
Disclaimer
Our Python library for Sign-In with Ethereum has not yet undergone a formal security audit. We welcome continued feedback on the usability, architecture, and security of this implementation.
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