What is Triple DES?
Triple DES (3DES) applies the DES cipher three times to each 64-bit block using an Encrypt–Decrypt–Encrypt (EDE) scheme with two or three keys, giving an effective strength of 112 or 168 bits. It was a transitional upgrade that extended the life of DES while AES was adopted. 3DES is now deprecated — NIST disallowed it after 2023 and its small 64-bit block is vulnerable to the Sweet32 attack — so use AES for new systems. Runs in your browser.
Deprecated: 3DES is being retired (Sweet32, NIST sunset). Use AES for new systems. Encryption runs locally in your browser.
How Triple DES works
3DES chains three DES operations per block:
- Encrypt the block with key K1.
- Decrypt the result with key K2.
- Encrypt again with key K3 (with two-key 3DES, K3 equals K1).
- A mode and IV chain the 64-bit blocks, and padding fills the final block.
How to use
- Enter the text you want to encrypt.
- Provide a key (and IV/mode settings where required).
- The encrypted output is produced in your browser.
- Share the ciphertext; share the key only through a safe channel.
Options explained
- Keying option — Two-key (112-bit) or three-key (168-bit) 3DES.
- Mode — ECB, CBC, CFB or OFB. Prefer CBC with a random IV.
- IV — Initialization vector for chaining modes.
- Padding — PKCS5/PKCS7 or NoPadding.
Common uses
- Legacy banking and payment systems (EMV, older POS).
- Interoperating with software that still requires 3DES.
- Maintaining existing encrypted data.
Frequently asked questions
Is 3DES still secure?
It is deprecated. Its 64-bit block is vulnerable to Sweet32; use AES for new systems.
What is the effective key size?
112 bits with two keys or 168 bits with three keys.
How do I decrypt 3DES?
Use the Triple DES Decryption tool with the same keys, mode, IV and padding.