Hawkynt

COMET-128-CHAM

NIST Lightweight Cryptography candidate providing authenticated encryption with 128-bit security. Uses CHAM-128/128 block cipher in CTR-like mode with 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/comet-cham.js

Parameters

Parameter	Supported values
Key sizes	16 bytes (128 bits)
Nonce sizes	16 bytes (128 bits)
Tag sizes	16 bytes (128 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

7 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	000102030405060708090a0b0c0d0e0f
associatedData	(empty)
input	(empty)
expected	04744f36aab6d5f430d7b70b65c82c24

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

Field	Value
key	000102030405060708090a0b0c0d0e0f
nonce	000102030405060708090a0b0c0d0e0f
associatedData	00
input	(empty)
expected	67e521a56812eba8916faeed6ef568fc

Vector 3 — NIST LWC KAT Count=17: Empty plaintext, 16-byte AD (full block)

Field	Value
key	000102030405060708090a0b0c0d0e0f
nonce	000102030405060708090a0b0c0d0e0f
associatedData	000102030405060708090a0b0c0d0e0f
input	(empty)
expected	d2eb1621d6416296b8d957b4230a3646

Vector 4 — NIST LWC KAT Count=34: 1-byte plaintext, empty AD

Field	Value
key	000102030405060708090a0b0c0d0e0f
nonce	000102030405060708090a0b0c0d0e0f
associatedData	(empty)
input	00
expected	da1a04685f162bc5e548aa0bf007fd1786

Vector 5 — NIST LWC KAT Count=35: 1-byte plaintext, 1-byte AD

Field	Value
key	000102030405060708090a0b0c0d0e0f
nonce	000102030405060708090a0b0c0d0e0f
associatedData	00
input	00
expected	16bf66003098f5f7d920b9a7d5c63ef814

Vector 6 — NIST LWC KAT Count=67: 2-byte plaintext, empty AD

Field	Value
key	000102030405060708090a0b0c0d0e0f
nonce	000102030405060708090a0b0c0d0e0f
associatedData	(empty)
input	0001
expected	da8e240846e93bdb066e02b53bd0fe8dc9c5

Vector 7 — NIST LWC KAT Count=69: 2-byte plaintext, 2-byte AD

Field	Value
key	000102030405060708090a0b0c0d0e0f
nonce	000102030405060708090a0b0c0d0e0f
associatedData	0001
input	0001
expected	19cb6a66f38fdf38c485cdea719e1367ac14

---

← All algorithms

This site is open source. Improve this page.