srp

What it is and what it does

SRP is a cryptographic authentication protocol that allows a client and server to verify each other's knowledge of a password without transmitting the password itself or relying on a trusted certificate authority. Unlike SSL/TLS or Kerberos, SRP derives server-side verification keys directly from user passwords, making it useful for systems where external infrastructure is unavailable or undesirable. The protocol provides mutual authentication—both sides must possess the correct password or key material for authentication to succeed—and produces a shared cryptographic key that can be used for subsequent symmetric encryption.

The srp package provides a Python implementation of this protocol. It depends only on six, making it lightweight and easy to integrate. The package is marked Production/Stable and has been in active development since 2011, though recent maintenance is minimal. It is suitable for applications that need password-based authentication without certificate management overhead, though you should verify that SRP meets your security and compatibility requirements before deploying it.

Use it for:

• Authenticate users in a custom application without setting up a certificate authority or external key server
• Implement mutual authentication between a client and server over an untrusted network connection
• Derive a shared encryption key from a password for symmetric-key encryption of subsequent communication
• Build authentication systems for embedded or isolated environments where certificate infrastructure is impractical

Worth the install?

AI-flagged interpretation of the facts on this page — verify before relying

Implements the Secure Remote Password (SRP) protocol for password-based mutual authentication over insecure networks without relying on external certificate infrastructure.

Yes, if you need SRP-based authentication and have verified that SRP meets your security requirements. The package is stable, has no known vulnerabilities, and installs easily with minimal dependencies. However, dormant maintenance (no releases in 651 days) means security updates or bug fixes may be slow; evaluate whether the protocol itself and this implementation align with your threat model before adopting it.

Install

srp on PyPI

pip install srp

uv add srp

poetry add srp

Installing srp

Before you install

Low friction installation with a single lightweight dependency (six). Maintenance is dormant—last commit was 2024-11-05 and no releases in 651 days—but the repository remains active and the package is marked Production/Stable.

License in practice

Licensed under MIT (permissive), so you can use, modify, and distribute the package freely in commercial or private projects with minimal restrictions.

Quickstart

pip install srp

import srp
# Create a user verifier and authentication session
user = srp.User(username, password)
verifier = user.get_verifier()
# Server and client exchange SRP messages to authenticate

Verify before relying

• Whether the package supports modern Python versions (requires_python is unspecified in the fact sheet)
• Whether SRP is suitable for contemporary security standards or if it has known limitations relative to modern alternatives
• Performance characteristics and typical use-case scale (e.g., throughput, latency)

Package facts

Evidence: srp-1.0.22-py3-none-any.whl

Tags

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