Hawkynt

COMET-64-CHAM

NIST Lightweight Cryptography candidate providing authenticated encryption with 64-bit blocks. Uses CHAM-64/128 block cipher in CTR-like mode with 64-bit authentication tag.

Properties

Property	Value
Category	Authenticated Encryption
Sub-category	Lightweight AEAD
Security status	🧪 Experimental
Complexity	Intermediate
Inventor	Donghoon Chang, Mohona Ghosh, Kishan Chand Gupta, Arpan Jati, Abhishek Kumar, Dukjae Moon, Indranil Ray, Somitra Kumar Sanadhya
Year	2019
Origin	🇮🇳 India
Source	algorithms/aead/comet64-cham.js

Parameters

Parameter	Supported values
Key sizes	16 bytes (128 bits)
Nonce sizes	15 bytes (120 bits)
Tag sizes	8 bytes (64 bits)

Capabilities

Flag	Value
SupportsDetached	No

Security

Status: 🧪 Experimental

No vulnerabilities are recorded for this implementation.

Documentation

• Official COMET Website
• NIST LWC Finalist Specification
• NIST LWC Project Page
• GitHub Reference Implementation

References

• NIST LWC Round 2 Submission Package (Reference C)

Test vectors

10 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.

Vector 1 — NIST LWC KAT Count=1: Empty plaintext, empty AD

Field	Value
key	000102030405060708090a0b0c0d0e0f
nonce	000102030405060708090a0b0c0d0e
associatedData	(empty)
input	(empty)
expected	e1123a4a8615d94a

Vector 2 — NIST LWC KAT Count=2: Empty plaintext, 1-byte AD

Field	Value
key	000102030405060708090a0b0c0d0e0f
nonce	000102030405060708090a0b0c0d0e
associatedData	00
input	(empty)
expected	9155fd4256f9fd88

Vector 3 — NIST LWC KAT Count=3: Empty plaintext, 2-byte AD

Field	Value
key	000102030405060708090a0b0c0d0e0f
nonce	000102030405060708090a0b0c0d0e
associatedData	0001
input	(empty)
expected	cf999e648f2d3a81

Vector 4 — NIST LWC KAT Count=9: Empty plaintext, 8-byte AD (full block)

Field	Value
key	000102030405060708090a0b0c0d0e0f
nonce	000102030405060708090a0b0c0d0e
associatedData	0001020304050607
input	(empty)
expected	912f24ea7c82e9e4

Vector 5 — NIST LWC KAT Count=17: Empty plaintext, 16-byte AD

Field	Value
key	000102030405060708090a0b0c0d0e0f
nonce	000102030405060708090a0b0c0d0e
associatedData	000102030405060708090a0b0c0d0e0f
input	(empty)
expected	4b6fcf412cacf2fe

Vector 6 — NIST LWC KAT Count=34: 1-byte plaintext, empty AD

Field	Value
key	000102030405060708090a0b0c0d0e0f
nonce	000102030405060708090a0b0c0d0e
associatedData	(empty)
input	00
expected	8b55b6a35ea7f8ea01

Vector 7 — NIST LWC KAT Count=35: 1-byte plaintext, 1-byte AD

Field	Value
key	000102030405060708090a0b0c0d0e0f
nonce	000102030405060708090a0b0c0d0e
associatedData	00
input	00
expected	5087ec65cc665179ac

Vector 8 — NIST LWC KAT Count=67: 2-byte plaintext, empty AD

Field	Value
key	000102030405060708090a0b0c0d0e0f
nonce	000102030405060708090a0b0c0d0e
associatedData	(empty)
input	0001
expected	8bc349e9c18dd8eb5dc7

Vector 9 — NIST LWC KAT Count=68: 2-byte plaintext, 1-byte AD

Field	Value
key	000102030405060708090a0b0c0d0e0f
nonce	000102030405060708090a0b0c0d0e
associatedData	00
input	0001
expected	503556a8e9ef057d37a0

Vector 10 — NIST LWC KAT Count=100: 3-byte plaintext, empty AD

Field	Value
key	000102030405060708090a0b0c0d0e0f
nonce	000102030405060708090a0b0c0d0e
associatedData	(empty)
input	000102
expected	8bc3311fb743e202f0e7b8

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