Hybrid Public Key Encryption (HPKE)

Created

  • 2021-11-16

Last Updated

  • 2026-04-16

Available Formats

HPKE KEM Identifiers

Registration Procedure(s)

  • Specification Required

Expert(s)

  • Christopher Wood, Richard Barnes

Reference

Request an Assignment

https://www.iana.org/form/protocol-assignment

Available Formats

Value KEM Nsecret Nenc Npk Nsk Auth Reference
0x0000 Reserved N/A N/A N/A N/A yes RFC 9180
0x0001-0x000F Unassigned
0x0010 DHKEM(P-256, HKDF-SHA256) 32 65 65 32 yes NISTCurves; RFC 5869
0x0011 DHKEM(P-384, HKDF-SHA384) 48 97 97 48 yes NISTCurves; RFC 5869
0x0012 DHKEM(P-521, HKDF-SHA512) 64 133 133 66 yes NISTCurves; RFC 5869
0x0013 DHKEM(CP-256, HKDF-SHA256) 32 32 32 32 Yes NISTCurves; RFC 6090; draft-irtf-cfrg-dnhpke-01
0x0014 DHKEM(CP-384, HKDF-SHA384) 48 48 48 48 Yes NISTCurves; RFC 6090; draft-irtf-cfrg-dnhpke-01
0x0015 DHKEM(CP-521, HKDF-SHA512) 64 66 66 66 Yes NISTCurves; RFC 6090; draft-irtf-cfrg-dnhpke-01
0x0016 DHKEM(secp256k1, HKDF-SHA256) 32 65 65 32 yes Standards for Efficient Cryptography 2 (SEC 2); draft-wahby-cfrg-hpke-kem-secp256k1-01
0x0017-0x001F Unassigned
0x0020 DHKEM(X25519, HKDF-SHA256) 32 32 32 32 yes RFC 5869; RFC 7748
0x0021 DHKEM(X448, HKDF-SHA512) 64 56 56 56 yes RFC 5869; RFC 7748
0x0022 DHKEM(X25519+Elligator, HKDF-SHA256) 32 32 32 32 yes https://lsd.gnunet.org/lsd0011/; draft-schanzen-hpke-elligator-kem-01
0x0023-0x002F Unassigned
0x0030 X25519Kyber768Draft00 64 1120 1216 2432 no draft-westerbaan-cfrg-hpke-xyber768d00-02
0x0031-0x003F Unassigned
0x0040 ML-KEM-512 32 768 800 64 no draft-connolly-cfrg-hpke-mlkem-04
0x0041 ML-KEM-768 32 1088 1184 64 no draft-connolly-cfrg-hpke-mlkem-04
0x0042 ML-KEM-1024 32 1568 1568 64 no draft-connolly-cfrg-hpke-mlkem-04
0x0043-0x004F Unassigned
0x0050 MLKEM768-P256 32 1153 1249 32 no draft-ietf-hpke-pq-04
0x0051 MLKEM1024-P384 32 1665 1665 32 no draft-ietf-hpke-pq-04
0x0052-0x6479 Unassigned
0x647A X-Wing 32 1120 1216 32 no draft-connolly-cfrg-xwing-kem-06
0x647B-0xFFFF Unassigned

HPKE KDF Identifiers

Registration Procedure(s)

  • Specification Required

Expert(s)

  • Christopher Wood, Richard Barnes

Reference

Request an Assignment

https://www.iana.org/form/protocol-assignment

Available Formats

Value KDF Nh Reference
0x0000 Reserved N/A RFC 9180
0x0001 HKDF-SHA256 32 RFC 5869
0x0002 HKDF-SHA384 48 RFC 5869
0x0003 HKDF-SHA512 64 RFC 5869
0x0004-0x000F Unassigned
0x0010 SHAKE128 32 draft-ietf-hpke-pq-04
0x0011 SHAKE256 64 draft-ietf-hpke-pq-04
0x0012 TurboSHAKE128 32 draft-ietf-hpke-pq-04
0x0013 TurboSHAKE256 64 draft-ietf-hpke-pq-04
0x0014-0xFFFF Unassigned

HPKE AEAD Identifiers

Registration Procedure(s)

  • Specification Required

Expert(s)

  • Christopher Wood, Richard Barnes

Reference

Request an Assignment

https://www.iana.org/form/protocol-assignment

Available Formats

Value AEAD Nk Nn Nt Reference
0x0000 Reserved N/A N/A N/A RFC 9180
0x0001 AES-128-GCM 16 12 16 GCM
0x0002 AES-256-GCM 32 12 16 GCM
0x0003 ChaCha20Poly1305 32 12 16 RFC 8439
0x0004-0xFFFE Unassigned
0xFFFF Export-only N/A N/A N/A RFC 9180