Online Crypto Tool

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A frontend encryption/decryption tool based on Crypto.js. All operations are performed locally in your browser - your data never leaves your device.

Features

Symmetric Encryption

• AES - Advanced Encryption Standard, the most popular symmetric encryption algorithm
• DES - Data Encryption Standard (legacy, recommend using AES instead)
• TripleDES - Triple DES, more secure than DES but slower
• Blowfish - Fast, secure symmetric encryption with variable key length
• Rabbit - High-performance stream cipher, suitable for real-time encryption
• RC4 - Stream cipher, simple and fast
• RC4Drop - Improved RC4 version with better security

Asymmetric Encryption (Public Key)

• RSA - RSA asymmetric encryption algorithm

  • Key sizes: 1024, 2048, 4096 bits
  • Encrypt/Decrypt mode: RSA-OAEP
  • Sign/Verify mode: RSA-PSS
  • Key formats: PEM, DER (Hex), Base64

• ECDSA - Elliptic Curve Digital Signature Algorithm

  • Supported curves: P-256, P-384, P-521
  • Features: Sign/Verify
  • Key format: JWK (JSON Web Key)

• ECDH - Elliptic Curve Diffie-Hellman

  • Supported curves: P-256, P-384, P-521
  • Features: Derive shared key (for AES-256-GCM)
  • Key format: JWK

• Ed25519 - EdDSA signature algorithm

  • Based on twisted Edwards curve
  • Features: Sign/Verify
  • Short keys (32 bytes), fast signing

Hash Algorithms

• MD5 - 128-bit hash (not recommended for security purposes)
• SHA-1 - 160-bit hash (being phased out)
• SHA-224 - SHA-2 family, 224-bit hash
• SHA-256 - SHA-2 family, 256-bit hash, widely used
• SHA-384 - SHA-2 family, 384-bit hash
• SHA-512 - SHA-2 family, 512-bit hash, highly secure
• SHA-3 - Next generation hash algorithm based on Keccak
• RIPEMD-160 - 160-bit hash

HMAC

• Hash-based Message Authentication Code for data integrity and authenticity verification

Encoding Tools

• Base64 - Base64 encode/decode
• Hex - Hexadecimal encode/decode
• Latin1 - ISO-8859-1 encode/decode
• UTF-8 - UTF-8 byte encoding viewer
• Universal Converter - Auto-detect input format and convert to all other formats

Supported input formats for Universal Converter:

• UTF-8 String (plain text)
• Hex (e.g., 48656c6c6f)
• Base64
• Inline (e.g., \x48\x65\x6c\x6c\x6f)
• C-Array (e.g., unsigned char data[] = { 0x48, 0x65, 0x6C };)
• Python (e.g., data = [ 0x48, 0x65, 0x6C ])

Key Derivation

• PBKDF2 - Password-based key derivation function
• EvpKDF - OpenSSL EVP key derivation function

Advanced Options

Cipher Modes

• CBC (Cipher Block Chaining) - Recommended
• ECB (Electronic Codebook) - Not recommended (insecure)
• CFB (Cipher Feedback)
• OFB (Output Feedback)
• CTR (Counter Mode)

Padding Modes

• PKCS#7 (Most common)
• Zero Padding
• No Padding
• ISO/IEC 9797-1
• ANSI X.923

Key Formats

• String (UTF-8)
• Hex
• Base64
• Latin1

Security & Privacy

• All encryption/decryption operations are performed locally in your browser
• No data is uploaded to any server
• Supports auto-generated random keys
• Dark/Light theme support
• Chinese/English language support (auto-detect based on browser settings)

Usage

Simply open index.html in your browser. No installation or server required.

Technology

• Pure HTML/CSS/JavaScript
• Crypto.js for symmetric encryption, hash, etc.
• Web Crypto API for asymmetric encryption (RSA, ECDSA, ECDH, Ed25519)
• Responsive design for desktop and mobile

Notes

• Asymmetric encryption algorithms (RSA, ECDSA, ECDH, Ed25519) only work on HTTPS or localhost
• RSA encryption has data length limits (~190 bytes max for 2048-bit keys)

License

MIT License

Author

Security Notes