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

SEED uses a fixed 128-bit key and supports ECB, CBC, CFB, and OFB modes.

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

1. Select encrypt or decrypt mode.
2. Configure mode, padding, key, and IV.
3. Enter text and run processing.
4. 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.