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RSA Digital Signature - Secure Message Authentication

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Create secure digital signatures with RSA private key authentication. Sign messages, documents, and transactions using professional RSA signature technology, ensuring authenticity, integrity, and non-repudiation for secure communications and legal compliance.

RSA Private Key

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Digital Signature

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Digital Signatures

Digital signatures provide authenticity and non-repudiation. Anyone with your public key can verify that this signature was created by your private key.

RSA Digital Signature: Professional Message Authentication

Create legally binding digital signatures with RSA private key technology. RSA digital signatures provide cryptographic proof of message authenticity, data integrity, and signer identity. Essential for document authentication, code signing, financial transactions, and any application requiring non-repudiation and secure identity verification.

Professional Authentication: RSA signatures provide legally recognized proof of authenticity and are accepted in court proceedings and regulatory compliance.

Why Use RSA Digital Signatures?

  • Legal Non-Repudiation: Create legally binding signatures that prevent signers from denying they signed documents.
  • Message Authentication: Prove message authenticity and verify sender identity with cryptographic certainty.
  • Data Integrity: Detect any tampering or modification of signed documents or messages.
  • Industry Standard: Widely accepted in government, finance, healthcare, and legal industries worldwide.
  • PKI Integration: Works seamlessly with Public Key Infrastructure and certificate authorities.
  • Multiple Hash Support: Compatible with SHA-256, SHA-512, and other cryptographic hash functions.
  • Flexible Padding: Supports PKCS#1 v1.5 and PSS padding schemes for different security requirements.
  • Privacy Protection: All signing happens locally - your private keys never leave your browser.

Frequently Asked Questions (FAQs)

1. What is the difference between RSA encryption and RSA signatures?

RSA encryption provides confidentiality using public keys, while RSA signatures provide authenticity using private keys.

2. Are RSA signatures legally binding?

Yes, RSA signatures provide non-repudiation and are legally recognized in most jurisdictions for digital contracts and documents.

3. Which hash function should I use with RSA signatures?

SHA-256 is recommended for most applications. Use SHA-512 for higher security or when required by specific standards.

4. Is my RSA private key sent to any servers?

No, all signing happens locally in your browser. Your private keys and data never leave your device for complete security.

5. Can I sign large documents with RSA?

RSA signs document hashes, not the documents directly. This allows signing documents of any size efficiently.

6. What is the difference between PKCS#1 and PSS padding?

PSS is more secure and recommended for new applications, while PKCS#1 v1.5 is used for legacy compatibility.

7. Can I sign software code with RSA?

Yes, RSA signatures are perfect for code signing, ensuring software authenticity and integrity for users and organizations.

8. How do I verify an RSA signature?

Use our RSA signature verification tool with the original message, signature, and the signer's public key.

9. Can I create timestamps with RSA signatures?

Yes, include timestamp information in signed messages to create legally binding time-stamped digital signatures.

10. What key size should I use for RSA signatures?

Use 2048-bit minimum for new applications, 4096-bit for high security. Avoid 1024-bit keys due to security concerns.

11. Can I sign emails with RSA?

Yes, RSA signatures are used in S/MIME and PGP email security systems for email authentication and integrity.

12. How do RSA signatures prevent tampering?

Any change to the signed message will cause signature verification to fail, providing guaranteed tamper detection.

13. Can I use RSA signatures for API authentication?

Perfect for APIs! Sign requests to ensure they come from authorized sources and haven't been modified in transit.

14. What industries require RSA signatures?

Healthcare (HIPAA), finance (SOX), government (FIPS), legal services, and any industry requiring document authenticity.

15. Can I sign JSON Web Tokens (JWT) with RSA?

Yes, RSA signatures are commonly used for JWT signing (RS256, RS384, RS512) in OAuth and authentication systems.

16. How do I protect my RSA private key?

Store private keys securely, use strong passwords, consider hardware security modules (HSMs) for high-value applications.

17. Can I create multi-party signatures with RSA?

Yes, multiple parties can sign the same document with their individual RSA keys for multi-signature authentication.

18. What happens if my private key is compromised?

Immediately revoke associated certificates and generate new key pairs. All signatures from the compromised key become untrusted.

19. Does the tool work offline?

Yes, after initial page load, all signing operations work completely offline for maximum security and privacy protection.

20. Is this RSA signature tool free?

Yes, completely free for professional, legal, and educational use with no registration or limitations.

Conclusion

Our RSA Digital Signature tool provides professional-grade authentication capabilities for modern business and legal requirements. Whether you're signing contracts, authenticating software, or implementing secure API communications, RSA signatures offer the trust and non-repudiation essential for today's digital world. Create legally binding, tamper-evident signatures with complete privacy and security.