IDEA Encryption/Decryption
Online IDEA (International Data Encryption Algorithm) encryption/decryption tool with 128-bit fixed key, supporting CBC, ECB, CFB, OFB, RAW modes.
Key Features
128-bit fixed key length provides strong security
8.5 rounds of encryption ensure thorough confusion
Input Format / Output Format
About IDEA (International Data Encryption Algorithm)
IDEA (International Data Encryption Algorithm) is a symmetric key block cipher designed by Xuejia Lai and James Massey at ETH Zurich in 1991. It was intended as a replacement for the Data Encryption Standard (DES) and has been widely used in security applications such as PGP.
| Algorithm | IDEA (International Data Encryption Algorithm) |
| Key Size | 128 bits (16 bytes) - Fixed |
| Block Size | 64 bits (8 bytes) |
| Structure | 8.5 rounds of encryption |
| Rounds | 8.5 rounds |
Key Features
128-bit fixed key length provides strong security
64-bit block size for data processing
8.5 rounds of encryption ensure thorough confusion
Patent expired since 2012, free to use worldwide
Encryption Modes
CBC (Cipher Block Chaining): Each block of plaintext is XORed with the previous ciphertext block before being encrypted. Requires an IV. Most common and secure mode.
ECB (Electronic Codebook): Each block is encrypted independently. No IV needed. Identical plaintext blocks are encrypted into identical ciphertext blocks, revealing patterns.
CFB (Cipher Feedback): Turns a block cipher into a self-synchronizing stream cipher. Requires an IV. Output is fed back to the shift register.
OFB (Output Feedback): Turns a block cipher into a synchronous stream cipher. Requires an IV. Generates keystream blocks, which are then XORed with the plaintext blocks.
RAW (Direct Block): Direct block encryption mode without any chaining or feedback mechanism. No IV needed. Each block is encrypted independently.
Algorithm Comparison
| Algorithm | Key Length | Block Size | Security | Speed |
|---|---|---|---|---|
| IDEA | 128 bits | 64 bits | Good | Fast |
| Blowfish | 32-448 bits | 64 bits | Good | Fast |
| AES | 128/192/256 bits | 128 bits | Excellent | Fast |
| Twofish | 128/192/256 bits | 128 bits | Excellent | Fast |
Use Cases
Legacy system compatibility and maintenance
PGP (Pretty Good Privacy) implementations
Educational purposes and cryptography research
Cryptographic history research and analysis
Security Recommendations
Key Length: IDEA uses a fixed 128-bit key, providing good security.
Mode Selection: Prefer CBC mode and avoid ECB for sensitive data.
Random IV: Must use a unique random IV (Initialization Vector) for every encryption.
Modern Alternative: For new applications, consider using modern algorithms like AES-256.