2021-11-16 2025-09-18 Christopher Wood, Richard Barnes Specification Required 0x0000 Reserved N/A N/A N/A N/A yes 0x0001-0x000F Unassigned 0x0010 DHKEM(P-256, HKDF-SHA256) 32 65 65 32 yes NISTCurves 0x0011 DHKEM(P-384, HKDF-SHA384) 48 97 97 48 yes NISTCurves 0x0012 DHKEM(P-521, HKDF-SHA512) 64 133 133 66 yes NISTCurves 0x0013 DHKEM(CP-256, HKDF-SHA256) 32 32 32 32 Yes NISTCurves 0x0014 DHKEM(CP-384, HKDF-SHA384) 48 48 48 48 Yes NISTCurves 0x0015 DHKEM(CP-521, HKDF-SHA512) 64 66 66 66 Yes NISTCurves 0x0016 DHKEM(secp256k1, HKDF-SHA256) 32 65 65 32 yes Standards for Efficient Cryptography 2 (SEC 2) 0x0017-0x001F Unassigned 0x0020 DHKEM(X25519, HKDF-SHA256) 32 32 32 32 yes 0x0021 DHKEM(X448, HKDF-SHA512) 64 56 56 56 yes 0x0022 DHKEM(X25519+Elligator, HKDF-SHA256) 32 32 32 32 yes 0x0023-0x002F Unassigned 0x0030 X25519Kyber768Draft00 64 1120 1216 2432 no 0x0031-0x0039 Unassigned 0x0040 ML-KEM-512 32 768 800 64 no 0x0041 ML-KEM-768 32 1088 1184 64 no 0x0042 ML-KEM-1024 32 1568 1568 64 no 0x0043-0x6479 Unassigned 0x647a X-Wing 32 1120 1216 32 no 0x647b-0xFFFF Unassigned Christopher Wood, Richard Barnes Specification Required 0x0000 Reserved N/A 0x0001 HKDF-SHA256 32 0x0002 HKDF-SHA384 48 0x0003 HKDF-SHA512 64 0x0004-0xFFFF Unassigned Christopher Wood, Richard Barnes Specification Required 0x0000 Reserved N/A N/A N/A 0x0001 AES-128-GCM 16 12 16 GCM 0x0002 AES-256-GCM 32 12 16 GCM 0x0003 ChaCha20Poly1305 32 12 16 0x0004-0xFFFE Unassigned 0xFFFF Export-only N/A N/A N/A