Free Online RSA Encryption and Decryption Tool

This tool allows you to generate RSA key pairs, encrypt, and decrypt text using RSA encryption. You can either generate a new RSA key pair or use your existing public and private keys for encryption and decryption operations.

Generate RSA Key Pair

Key Size

Public Key (X.509 Format)

Encryption

Private Key (PKCS8 Format)

Decryption

What Can You Do With This RSA Tool?

Generate RSA Keys

Create secure RSA key pairs from 512 to 4096 bits for your encryption needs.

Encrypt Messages

Protect sensitive text using RSA public key encryption with multiple algorithms.

Decrypt Messages

Decode encrypted messages using your RSA private key quickly and securely.

Why Use Our RSA Encryption Tool?

  • Free & Easy to Use - No registration required, works directly in your browser
  • Multiple Algorithms - Supports RSA, RSA/ECB/PKCS1Padding, OAEPWithSHA-1AndMGF1Padding, and more
  • Secure Processing - All encryption/decryption happens in your browser - we never see your keys or data
  • Key Size Options - Choose from 512-bit to 4096-bit RSA keys for different security needs

How to Use This RSA Encryption/Decryption Tool

This tool is designed to help you generate RSA key pairs, encrypt text using a public or private key, and decrypt text using the corresponding key. Below is a step-by-step guide on how to use this tool effectively:

1. Generating RSA Key Pairs

  • Step 1: Select the desired RSA Key Size from the dropdown menu. Common key sizes are 2048 bits (default) and 4096 bits for stronger security.
  • Step 2: Click the Generate RSA Key Pair button. This will generate a new public and private key pair.
  • Step 3: Copy or download the generated keys for future use. Ensure you store the private key securely, as it is required for decryption.
  • Step 4: You can skip above steps, if you already have a public and private key, paste them into the respective boxes labeled Public Key and Private Key to use them.

2. Encrypting Text

  • Step 1: Paste or type the text you want to encrypt in the Text To Encrypt field.
  • Step 2: Choose the Transformation Algorithm from the dropdown. The default is RSA/ECB/PKCS1Padding, which is widely supported.
  • Step 3: Select the Key To Use For Encryption (either public or private key). Typically, encryption is done using the public key.
  • Step 4: Click the Encrypt button. The encrypted output will be displayed in the Encrypted Text field.

3. Decrypting Text

  • Step 1: Paste the encrypted text in the Text To Decrypt field.
  • Step 2: Choose the Transformation Algorithm used during encryption.
  • Step 3: Select the Key To Use For Decryption (either public or private key). Typically, decryption is done using the private key.
  • Step 4: Click the Decrypt button. The decrypted text will be displayed in the Decrypted Text field.

Important Considerations

While using this tool, keep the following points in mind to avoid common pitfalls:

  • Key Size and Algorithm Compatibility: Not all key sizes work with every transformation algorithm. For example, smaller key sizes (e.g., 512 bits) may not work with advanced algorithms like RSA/ECB/OAEPWithSHA-256AndMGF1Padding. Always use a key size of at least 2048 bits for compatibility and security.
  • Encrypting with a Private Key: While it is technically possible to encrypt with a private key, this is not a standard practice. Encryption is typically done with the public key, and decryption is done with the private key. Encrypting with a private key can lead to confusion and security risks.
  • Key Management: Always store your private key securely. If the private key is lost, encrypted data cannot be decrypted. Similarly, if the private key is compromised, the security of your encrypted data is at risk.
  • Performance: Larger key sizes (e.g., 4096 bits) provide stronger security but may result in slower encryption and decryption operations. Choose a key size that balances security and performance for your use case.

Understanding RSA Encryption

RSA (Rivest-Shamir-Adleman) is a widely used asymmetric encryption algorithm. It relies on the mathematical properties of large prime numbers and modular arithmetic. Here’s a brief overview of how RSA works:

  • Key Generation: Two large prime numbers are used to generate a public key (used for encryption) and a private key (used for decryption). The public key can be shared openly, while the private key must be kept secret.
  • Encryption: The sender uses the recipient's public key to encrypt the message. Once encrypted, the message can only be decrypted using the corresponding private key.
  • Decryption: The recipient uses their private key to decrypt the message. Without the private key, the encrypted message cannot be decrypted, ensuring confidentiality.

RSA is commonly used for securing sensitive data, digital signatures, and key exchange in protocols like SSL/TLS.

Common Challenges

While RSA is a robust encryption method, users may face the following challenges:

  • Data Size Limitations: RSA encryption has a limit on the amount of data that can be encrypted in a single operation. For larger data, hybrid encryption (combining RSA with symmetric encryption like AES) is recommended.
  • Algorithm Mismatch: Ensure the same transformation algorithm is used for both encryption and decryption. Mismatched algorithms will result in decryption errors.
  • Key Corruption: If the public or private key is corrupted or altered, encryption or decryption will fail. Always verify the integrity of your keys.

Conclusion

This RSA Encryption/Decryption Tool simplifies the process of generating keys, encrypting, and decrypting text. By following the guidelines above, you can ensure secure and effective use of RSA encryption. Always prioritize key security and choose appropriate key sizes and algorithms for your specific needs.