EDE (Encrypt-Decrypt-Encrypt) mode applies Encrypt-Decrypt-Encrypt operations using the underlying block cipher. Supports both 2-key mode (K1-K2-K1) and 3-key mode (K1-K2-K3). This is the standard triple operation mode used in 3DES and provides compatibility with single encryption when K1=K2=K3.
| Property | Value |
|---|---|
| Category | Cipher Modes |
| Sub-category | Block Cipher Mode |
| Security status | 🎓 Educational Only |
| Complexity | Intermediate |
| Inventor | IBM (Walter Tuchman) |
| Year | 1978 |
| Origin | 🇺🇸 United States |
| Source | algorithms/modes/ede.js |
| Flag | Value |
|---|---|
RequiresIV |
No |
Status: 🎓 Educational Only
| Issue | Description | Mitigation |
|---|---|---|
| Meet-in-the-middle | Effective security reduced to 2n bits for 2-key variant | — |
| Sweet32 | Birthday attacks on 64-bit block ciphers after 2^32 blocks | — |
| Key reuse | 2-key variant (K1-K2-K1) has lower effective security than 3-key | — |
2 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.
Vector 1 — NIST TDES_ECB - three-key TDEA (EDE3), two blocks
| Field | Value |
|---|---|
cipher |
DES |
key |
0123456789abcdef23456789abcdef01456789abcdef0123 |
input |
6bc1bee22e409f96e93d7e117393172aae2d8a571e03ac9c9eb76fac45af8e51 |
expected |
714772f339841d34267fcc4bd2949cc3ee11c22a576a303876183f99c0b6de87 |
Vector 2 — NIST TDES_ECB - two-key TDEA (EDE2, K3 = K1), two blocks
| Field | Value |
|---|---|
cipher |
DES |
key |
0123456789abcdef23456789abcdef010123456789abcdef |
input |
6bc1bee22e409f96e93d7e117393172aae2d8a571e03ac9c9eb76fac45af8e51 |
expected |
06ede3d82884090aff322c19f0518486730576972a666e58b6c88cf107340d3d |