SEED-128 block encryption

Overview & Cryptographic Context

SEED is a 128-bit Feistel block cipher developed by the Korea Information Security Agency (KISA) in 1998 and standardized internationally in ISO/IEC 18033-3 and IETF RFC 4269 (TTAK.KO-12.0004). Operating over 16 rounds with a 128-bit (16-byte) key and 16-byte block size, SEED remains widely used in Korean financial, public-sector, and legacy TLS/CMS systems alongside ARIA and LEA.

To verify core block-cipher round transformations against official Known Answer Tests (KAT), you must isolate the raw permutation from chaining or padding overhead. This workflow runs SEED Encrypt in Electronic Codebook (ECB) mode with Padding set to None, verifying Vector 4 of RFC 4269 Appendix B.4.

Pipeline Architecture & Wiring Flow

1. Block-Aligned Inputs (Workflow Input): Supplies the exact 16-byte key and 16-byte plaintext block defined in the KISA SEED specification.
2. Single-Block Feistel Transform (SEED Encrypt): Configured with mode = "ECB" and padding = "None". In ECB mode, the IV, Nonce, AAD, and Auth Tag ports are hidden automatically.
3. Ciphertext Inspection (Workflow Output): Emits the resulting 16-byte ciphertext block without extra padding blocks.

Nodes & Configuration

Node reference → · ECB Mode specification →

Inputs, Outputs & Test Vector Verification

Verification Source: RFC 4269 Appendix B.4 / KISA SEED 128 Algorithm Test Vectors (vector 4)

Inputs

Expected Outputs