What is Triple DES?
Triple DES decryption reverses 3DES encryption, recovering the plaintext using the same keys, mode, IV and padding. Because 3DES uses the Encrypt–Decrypt–Encrypt scheme, decryption applies Decrypt–Encrypt–Decrypt with the same keys. 3DES is deprecated, so use this mainly for legacy data; choose AES for new work. Runs entirely in your browser.
Match the settings: use the same keys, mode, IV and padding from encryption. Runs locally in your browser.
How Triple DES works
3DES decryption reverses the EDE chain:
- Decrypt the block with key K3.
- Encrypt the result with key K2.
- Decrypt again with key K1.
- The mode and IV undo block chaining and padding is removed.
How to use
- Paste the Triple DES ciphertext.
- Enter the same key and settings used to encrypt.
- The decrypted text appears in the output.
Options explained
- Keying option — Two-key or three-key, matching what was used to encrypt.
- Mode / IV — Must match the encryption settings.
- Padding — Must match (PKCS5/PKCS7 or NoPadding).
Common uses
- Reading 3DES-encrypted legacy data.
- Payment and banking interop.
- Migrating old encrypted records.
Frequently asked questions
Why does decryption fail?
The keys, mode, IV or padding do not match the encryption settings.
Is 3DES safe to keep using?
It is deprecated; migrate to AES when possible.
How do I encrypt instead?
Use the Triple DES Encryption tool.