开
RC2 Encryption
Tool Description
RC2 Encryption is an online RC2 (Rivest Cipher 2) encryption/decryption tool that is free and requires no installation — just open the page to use it. RC2 is a block cipher designed by Ron Rivest in 1987 with a 64-bit (8-byte) block size, supporting variable key length (1~128 bytes) and independently adjustable effective key bits. This tool supports ECB / CBC cipher modes and Base64 / Hex / Latin1 / UTF-8 output encodings. All operations run locally in your browser — no data is ever uploaded to any server.
How to Use
- Choose Key Size
In the parameters panel, choose the key size: 40-bit (5 bytes), 64-bit (8 bytes), or 128-bit (16 bytes).
- Generate Key
Enter a key or click the random button to generate a key, and choose the effective key bits (controls encryption strength).
- Choose Cipher Mode
Choose the cipher mode (ECB / CBC). CBC mode requires an IV (8 bytes).
- Select Encoding & Input
Select the output encoding (Base64 / Hex / Latin1 / UTF-8), then paste or type your text in the input area.
- Run Encrypt/Decrypt
Click "Encrypt" or "Decrypt" to execute. The result appears on the right — copy or download as needed.
Use Cases
- Legacy System Compatibility: RC2 was used in early S/MIME email encryption and PKCS#12 certificates — use this tool for compatibility with legacy encrypted data
- Cryptography Learning: RC2 is a classic case study for understanding block cipher design and key expansion mechanisms, ideal for cryptography education and research
- Data Migration: When dealing with old databases or files encrypted with RC2, use this tool for decryption and format conversion
Key Advantages
- Free & No Install
The tool is completely free and works in the browser — no client software to download or install.
- Local & Private
All encryption/decryption runs locally in your browser; your keys and data never leave your device.
- Flexible Modes
Supports ECB / CBC cipher modes and configurable effective key bits, meeting both compatibility and strength needs.
- Multiple Encodings
Offers Base64, Hex, Latin1, and UTF-8 output encodings for flexible transmission and storage.
- Variable Key Length
Supports 1~128-byte variable key length, compatible with various legacy and new key specs.
- Easy to Use
Clear form parameters with one-click copy and download — no cryptography background needed.
RC2 vs Other Encryption Algorithms
Understand the differences between RC2, DES, and AES:
| Dimension | RC2 | DES | AES |
|---|---|---|---|
| Algorithm Type | Block Cipher | Block Cipher | Block Cipher |
| Key Length | 1~128 bytes | 8 bytes | 16/24/32 bytes |
| Block Size | 64-bit | 64-bit | 128-bit |
| Security | Not recommended (known attacks exist) | Not recommended (56-bit can be brute-forced) | High, current standard |
| Use Cases | Legacy systems, PKCS#12 | Legacy system compatibility | Current mainstream standard |
FAQ
RC2 (Rivest Cipher 2) is a block cipher designed by Ron Rivest in 1987, with a 64-bit block size. RC4 is a stream cipher. They are fundamentally different: RC2 divides data into 8-byte blocks for encryption and requires padding and an IV (in CBC mode); RC4 encrypts byte by byte as a stream and requires no padding or IV.
Effective Key Bits is a unique design feature of RC2 that controls the actual encryption strength of the key. It originated from US export controls on encryption software in the 1980s — software with key strength not exceeding 40 bits could be exported. Using a 128-bit key with effective bits set to 40 provides only 40-bit security. For modern use, set effective key bits equal to the key length.
RC2 has known security vulnerabilities such as related-key attacks and is no longer recommended for security-sensitive applications. For new systems, AES is recommended. RC2 is primarily useful for compatibility with legacy data such as early S/MIME email encryption and PKCS#12 certificates.
This tool supports ECB (Electronic Codebook) and CBC (Cipher Block Chaining) modes. ECB mode does not require an IV but is less secure — identical plaintext produces identical ciphertext. CBC mode requires an 8-byte IV and provides higher security; it is the recommended mode.
Yes. When decrypting, you must use the exact same key, effective key bits, cipher mode, and output encoding that were used for encryption; otherwise, decryption will fail or produce garbage output. The IV must also match (except in ECB mode).
Yes. Text is processed as UTF-8, so Chinese, Japanese, Korean, and any Unicode characters encrypt and decrypt normally. Output uses Base64, Hex, Latin1, or UTF-8 encoding for safe transmission and storage.
No. All encryption/decryption operations run entirely in your browser. Your keys and data never leave your device.
Possible causes: ① the key or effective key bits are incorrect; ② the mode differs between encryption and decryption; ③ the IV differs (CBC mode); ④ the output encoding is wrong; ⑤ the input is not valid RC2 encrypted data. Make sure every parameter matches encryption exactly.
CBC is more secure. ECB doesn't use an IV, so identical plaintext blocks produce identical ciphertext and leak data patterns. CBC chains blocks using an IV, giving higher security — prefer CBC.
As a block cipher, RC2 processes 8-byte blocks and suits text and moderate-sized data. This tool focuses on text encryption/decryption; for large files use chunked processing with CBC mode and manage keys and IVs carefully.
Local processing means your keys and data are never uploaded to any server, eliminating leakage risks in transit and storage. It also works offline with faster response and stronger privacy.
For new projects, RC2 is not recommended — it has known vulnerabilities such as related-key attacks, and AES is the modern standard. This tool is best for compatibility and decrypting legacy RC2-encrypted data.
Content last updated：2026-07-15
DES Encryption
Online DES/2DES/3DES encryption and decryption tool, supporting all encryption modes and padding methods. Fully processed locally in the browser for security and efficiency.
AES Encryption
Online AES encryption and decryption tool, supporting AES-128/192/256, covering all encryption modes and padding methods, secure, efficient, and easy to operate.
3DES Encryption
Online 3DES encryption/decryption tool, supporting all encryption modes and padding methods, fully processed locally in the browser to ensure data security.
RC4 Encryption
Online RC4 stream cipher encryption/decryption tool, supports multiple key lengths, one-click encryption and decryption, all operations are completed locally in the browser to ensure data security.
Rabbit Encryption
Online Rabbit stream cipher encryption/decryption tool, using a high-speed symmetric encryption algorithm, supporting multiple key lengths. All operations are performed locally in the browser to ensure data security.
IDEA Encryption
Online IDEA International Data Encryption Algorithm Tool, supporting multiple encryption modes including ECB/CBC/CFB/OFB/CTR. All operations are performed locally in the browser to ensure data security.
Blowfish Encryption
Online Blowfish encryption/decryption tool supporting 128/192/256/448-bit variable keys, ECB/CBC/CFB/OFB modes, and multiple padding methods. All operations are performed locally in the browser to ensure data security.
CAST Encryption
CAST-128 (CAST5) online encryption and decryption tool, supporting multiple encryption modes such as ECB/CBC/CFB/OFB, flexible padding methods, and output encoding. All operations are performed locally in the browser, ensuring security and efficiency.
SM4 National Encryption
Online SM4 National Symmetric Encryption and Decryption Tool, supporting five working modes: ECB/CBC/CFB/OFB/CTR, and multiple padding methods. All operations are performed locally in the browser to ensure data security.
RSA Encryption and Decryption
Online RSA asymmetric encryption and decryption tool, supporting key pair generation, public key encryption and private key decryption, private key signing and public key verification. All operations are performed locally in the browser to ensure data security.
MD5 Encryption
Online MD5 hash encryption tool, supporting 16-bit/32-bit output, case switching, and file MD5 verification. All operations are completed locally in the browser, ensuring security and efficiency.
MD2 Encryption
MD2 Encryption Tool: Generate 32-bit MD2 hash values online, supporting uppercase/lowercase output and file verification.
SHA-1 Encryption
Online SHA-1 hash calculation tool for efficient text encryption and file integrity verification.
SHA-256 Encryption
Online SHA-256 hash calculation tool for quick text encryption and file integrity verification.
SHA-384 Encryption
Online SHA-384 hash calculation tool for fast text encryption and file integrity verification.
SHA-512 Encryption
Online SHA-512 hash calculation tool, supporting text encryption and file integrity verification, quickly generating secure hash values.
SM3 National Encryption
Online SM3 National Hash Encryption Tool, supports text hash calculation and file verification, outputs a 256-bit hash value, compliant with GM/T 0004-2012 national standard.
Base64 Encode/Decode
Online Base64 encode/decode tool, supporting text Base64 encoding and decoding, all done locally in the browser, safe and efficient.
URL Encode/Decode
Online URL encoding and decoding tool, supports intelligent encoding and decoding of URL parameters, automatically identifies URL structure, processes only the parameter part, completes entirely in the browser locally, safe and efficient.
UTF-8 Encode/Decode
Online UTF-8 encoding/decoding tool, supporting conversion between text and UTF-8 hexadecimal bytes. All processing is done locally in the browser, ensuring data security.
