SEED Encryption/Decryption

Online SEED encryption/decryption tool, Korean standard 128-bit block cipher, supporting CBC, ECB, CFB, OFB modes.

Algorithm Info

Note: SEED uses a fixed 128-bit key
Note: Supports ECB, CBC, CFB, and OFB modes

Cipher Mode

Padding

Key (128 bit / 16 bytes)

IV (Initialization Vector) (128 bit / 16 bytes)

Mode & Padding

Input Format

Output Format

Input

Documentation

This tool performs local SEED block-cipher encryption/decryption with common modes, paddings, and encoding formats.

Key Features

SEED support (128-bit key, 16 rounds)
ECB, CBC, CFB, and OFB modes
Multiple paddings and input/output formats
Text processing with one-click output copy

Steps

Select encrypt or decrypt mode.
Configure mode, padding, key, and IV.
Enter text and run processing.
Copy the output for downstream usage.

Notes

Correct IV length is usually required except ECB.
Keep mode, padding, encoding, and key parameters consistent across both sides.
Store key and IV securely in production environments.