EAX
EAX (Encrypt-then-Authenticate-then-Translate) is an authenticated encryption mode that combines CTR mode encryption with OMAC authentication. It provides both confidentiality and authenticity, supporting arbitrary-length nonces and associated authenticated data (AAD).
Properties
| Property |
Value |
| Category |
Cipher Modes |
| Sub-category |
Authenticated Encryption |
| Security status |
🛡️ Secure |
| Complexity |
Advanced |
| Inventor |
Bellare, Rogaway, Wagner |
| Year |
2003 |
| Origin |
🇺🇸 United States |
| Source |
algorithms/modes/eax.js |
Parameters
| Parameter |
Supported values |
| Tag sizes |
1 byte (8 bits) to 16 bytes (128 bits) |
Capabilities
| Flag |
Value |
SupportsDetached |
Yes |
Security
Status: 🛡️ Secure
Known vulnerabilities
| Issue |
Description |
Mitigation |
| Nonce Reuse |
Reusing nonce with same key breaks confidentiality and authenticity. Always use unique nonces. |
— |
| Implementation Attacks |
Vulnerable to timing attacks if not implemented with constant-time operations. |
— |
Documentation
References
- Handbook of Applied Cryptography — Chapter 9 - Authenticated Encryption
- OMAC Specification
Test vectors
5 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.
Vector 1 — Crypto++ Test Vector #1 - Empty plaintext
| Field |
Value |
cipher |
AES |
key |
233952dee4d5ed5f9b9c6d6ff80ff478 |
nonce |
62ec67f9c3a4a407fcb2a8c49031a8b3 |
aad |
6bfb914fd07eae6b |
tagSize |
16 |
input |
(empty) |
expected |
e037830e8389f27b025a2d6527e79d01 |
Vector 2 — Crypto++ Test Vector #2 - 2-byte plaintext
| Field |
Value |
cipher |
AES |
key |
91945d3f4dcbee0bf45ef52255f095a4 |
nonce |
becaf043b0a23d843194ba972c66debd |
aad |
fa3bfd4806eb53fa |
tagSize |
16 |
input |
f7fb |
expected |
19dd5c4c9331049d0bdab0277408f67967e5 |
Vector 3 — Crypto++ Test Vector #3 - 5-byte plaintext
| Field |
Value |
cipher |
AES |
key |
01f74ad64077f2e704c0f60ada3dd523 |
nonce |
70c3db4f0d26368400a10ed05d2bff5e |
aad |
234a3463c1264ac6 |
tagSize |
16 |
input |
1a47cb4933 |
expected |
d851d5bae03a59f238a23e39199dc9266626c40f80 |
Vector 4 — Crypto++ Test Vector #4 - 5-byte plaintext
| Field |
Value |
cipher |
AES |
key |
d07cf6cbb7f313bdde66b727afd3c5e8 |
nonce |
8408dfff3c1a2b1292dc199e46b7d617 |
aad |
33cce2eabff5a79d |
tagSize |
16 |
input |
481c9e39b1 |
expected |
632a9d131ad4c168a4225d8e1ff755939974a7bede |
Vector 5 — Crypto++ Test Vector #5 - 6-byte plaintext
| Field |
Value |
cipher |
AES |
key |
35b6d0580005bbc12b0587124557d2c2 |
nonce |
fdb6b06676eedc5c61d74276e1f8e816 |
aad |
aeb96eaebe2970e9 |
tagSize |
16 |
input |
40d0c07da5e4 |
expected |
071dfe16c675cb0677e536f73afe6a14b74ee49844dd |
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