DES Online Encryption and Decryption Tool
Four CBC/ECB/CFB/OFB modes, 8-byte key and IV, with Base64 or Hex output
DES Online Encryption and Decryption
DES was established as an encryption standard in 1977. Although it uses a 64-bit key, its effective key length is only 56 bits and it can be broken by brute force. This tool is intended for legacy-system interoperability, historical data decryption, and educational demonstrations, not for new security systems.
Core Features
The tool provides encryption and decryption tabs with CBC, ECB, CFB, and OFB modes. CBC is the default mode. Keys and IVs can be generated randomly. Ciphertext and IV values can be copied or downloaded and can also be filled directly into the decryption form.
Parameters
The key must be exactly 8 bytes, equivalent to 16 hexadecimal characters. The IV is also 8 bytes. If the IV is left blank during encryption, it is generated automatically. Decryption must use exactly the same IV. ECB does not use an IV, so the IV field is hidden when ECB is selected.
Output encoding can be Base64 or Hex. The encoding used for decryption must match the encoding used for the ciphertext.
Padding
CBC and ECB use PKCS#7 padding, and the resulting ciphertext length is a multiple of 8 bytes. CFB and OFB use stream feedback and do not add padding; ciphertext length is the same as plaintext length.
Errors
The tool validates key and IV lengths. Decryption failures and empty inputs provide specific guidance to help identify the problem.
Use Cases
Useful for legacy system interfaces, ciphertext stored in historical databases or archives, consistency checks when migrating from DES to AES, and learning about symmetric encryption.
Security
DES is no longer considered secure. Do not use it for new systems, production environments, or long-term storage. Use AES-256-GCM for new systems. ECB can reveal patterns in the original plaintext.
Privacy
The JavaScript library processes the key, IV, and plaintext locally in the browser. These values are not uploaded or stored on the server. Use test data only.
Perform DES encryption and decryption online
- Supports four modes: CBC, ECB, CFB, and OFB; selecting ECB automatically hides the IV field
- The key is fixed at 8 bytes, or 16 hexadecimal characters, and the IV is also 8 bytes; both can be generated randomly with one click
- Leaving the IV blank during encryption generates it automatically and displays it in the result; decryption must use exactly the same IV
- Output encoding supports Base64 or Hex, and both ciphertext and IV can be copied or downloaded
- One-click filling puts the ciphertext and IV into the decryption form for quick round-trip verification
- Invalid key or IV lengths and decryption failures display the specific reason