PyHPKE - A Python implementation of HPKE

PyHPKE is a HPKE (Hybrid Public Key Encryption) implementation written in Python.

You can install PyHPKE with pip:

$ pip install pyhpke

And then, you can use it as follows:

from pyhpke import AEADId, CipherSuite, KDFId, KEMId, KEMKey

# The sender side:
suite_s = CipherSuite.new(
    KEMId.DHKEM_P256_HKDF_SHA256, KDFId.HKDF_SHA256, AEADId.AES128_GCM
)
pkr = KEMKey.from_jwk(  # from_pem is also available.
    {
        "kid": "01",
        "kty": "EC",
        "crv": "P-256",
        "x": "Ze2loSV3wrroKUN_4zhwGhCqo3Xhu1td4QjeQ5wIVR0",
        "y": "HlLtdXARY_f55A3fnzQbPcm6hgr34Mp8p-nuzQCE0Zw",
    }
)
enc, sender = suite_s.create_sender_context(pkr)
ct = sender.seal(b"Hello world!")

# The recipient side:
suite_r = CipherSuite.new(
    KEMId.DHKEM_P256_HKDF_SHA256, KDFId.HKDF_SHA256, AEADId.AES128_GCM
)
skr = KEMKey.from_jwk(
    {
        "kid": "01",
        "kty": "EC",
        "crv": "P-256",
        "x": "Ze2loSV3wrroKUN_4zhwGhCqo3Xhu1td4QjeQ5wIVR0",
        "y": "HlLtdXARY_f55A3fnzQbPcm6hgr34Mp8p-nuzQCE0Zw",
        "d": "r_kHyZ-a06rmxM3yESK84r1otSg-aQcVStkRhA-iCM8",
    }
)
recipient = suite_r.create_recipient_context(enc, skr)
pt = recipient.open(ct)

assert pt == b"Hello world!"


# deriving a KEMKeyPair
keypair = suite_s.kem.derive_key_pair(b"some_ikm_bytes_used_for_key_derivation")

Index

• Installation
• Supported HPKE Modes and Cipher Suites
• Warnings and Restrictions
• Usage
• API Reference
• Test
• Contributing

Installation

You can install PyHPKE with pip:

$ pip install pyhpke

Supported HPKE Modes and Cipher Suites

PyHPKE supports all of the HPKE modes and cipher suites defined in RFC9180 below.

• modes
  • ✅ Base
  • ✅ PSK
  • ✅ Auth
  • ✅ AuthPSK
• KEMs (Key Encapsulation Machanisms)
  • ✅ DHKEM (P-256, HKDF-SHA256)
  • ✅ DHKEM (P-384, HKDF-SHA384)
  • ✅ DHKEM (P-521, HKDF-SHA512)
  • ✅ DHKEM (X25519, HKDF-SHA256)
  • ✅ DHKEM (X448, HKDF-SHA512)
• KDFs (Key Derivation Functions)
  • ✅ HKDF-SHA256
  • ✅ HKDF-SHA384
  • ✅ HKDF-SHA512
• AEADs (Authenticated Encryption with Associated Data)
  • ✅ AES-128-GCM
  • ✅ AES-256-GCM
  • ✅ ChaCha20Poly1305
  • ✅ Export Only

Warnings and Restrictions

Although this library has been passed all of the following official test vectors, it has not been formally audited.

• RFC9180 official test vectors provided on github.com/cfrg/draft-irtf-cfrg-hpke

Usage

from pyhpke import AEADId, CipherSuite, KDFId, KEMId, KEMKey

# The sender side:
suite_s = CipherSuite.new(
    KEMId.DHKEM_P256_HKDF_SHA256, KDFId.HKDF_SHA256, AEADId.AES128_GCM
)
pkr = KEMKey.from_jwk(
    {
        "kid": "01",
        "kty": "EC",
        "crv": "P-256",
        "x": "Ze2loSV3wrroKUN_4zhwGhCqo3Xhu1td4QjeQ5wIVR0",
        "y": "HlLtdXARY_f55A3fnzQbPcm6hgr34Mp8p-nuzQCE0Zw",
    }
)
enc, sender = suite_s.create_sender_context(pkr)
ct = sender.seal(b"Hello world!")

# The recipient side:
suite_r = CipherSuite.new(
    KEMId.DHKEM_P256_HKDF_SHA256, KDFId.HKDF_SHA256, AEADId.AES128_GCM
)
skr = KEMKey.from_jwk(
    {
        "kid": "01",
        "kty": "EC",
        "crv": "P-256",
        "x": "Ze2loSV3wrroKUN_4zhwGhCqo3Xhu1td4QjeQ5wIVR0",
        "y": "HlLtdXARY_f55A3fnzQbPcm6hgr34Mp8p-nuzQCE0Zw",
        "d": "r_kHyZ-a06rmxM3yESK84r1otSg-aQcVStkRhA-iCM8",
    }
)
recipient = suite_r.create_recipient_context(enc, skr)
pt = recipient.open(ct)

assert pt == b"Hello world!"

API Reference

See Documentation.

Test

You can run tests from the project root after cloning with:

$ tox

Contributing

We welcome all kind of contributions, filing issues, suggesting new features or sending PRs.