How Electronic Signatures Stay Secure

Electronic signatures have revolutionized the way we sign and manage documents, offering unmatched convenience and speed. But with this digital transformation comes a critical question: How do electronic signatures remain secure and trustworthy? This guide explores the robust security mechanisms behind eSignatures, including advanced encryption, public key cryptography, secure cloud storage, and compliance with global legal standards. Whether you're a business owner, legal professional, or everyday user, understanding these protections will help you confidently embrace electronic signatures for your most important agreements.

How Electronic Signatures Ensure Security

The security of electronic signatures is built on a foundation of advanced cryptographic techniques and strict compliance protocols. When you sign a document electronically, your signature is not just a digital scribble—it's a complex, encrypted data package that uniquely identifies you and binds your identity to the document. This process ensures that any attempt to alter the signed document after the fact will be detected immediately. Leading eSignature platforms like SignNow employ multiple layers of security, including dual-factor authentication, digital certificates, and court-admissible audit trails, to guarantee the authenticity and integrity of every signature. These measures work together to prevent forgery, unauthorized access, and tampering, making eSignatures as legally binding and trustworthy as traditional handwritten signatures.

Understanding Public Key Cryptography

At the heart of electronic signature security lies public key cryptography, also known as asymmetric cryptography. This system uses a pair of keys—a public key and a private key—to encrypt and decrypt data. The private key is securely held by the signer, while the public key is available to anyone who needs to verify the signature. When you sign a document, your private key creates a unique encrypted signature. Anyone with your public key can then verify that the signature is authentic and that the document hasn't been altered. This process ensures both the identity of the signer and the integrity of the signed document.


This diagram illustrates how a message is encrypted with a private key and decrypted with a public key, ensuring secure and verifiable communication.

Encryption Algorithms Used in Electronic Signatures

Electronic signatures rely on industry-standard encryption algorithms to protect data during every stage of the signing process. SignNow, for example, uses a combination of RSA (Rivest–Shamir–Adleman) and ECDSA (Elliptic Curve Digital Signature Algorithm) to secure signatures during transmission. RSA is based on the mathematical challenge of factoring large prime numbers, making it extremely difficult to crack without the correct key. ECDSA, on the other hand, uses the properties of elliptic curves to provide strong security with smaller key sizes, which is especially efficient for mobile and web applications.


This image shows two elliptic curves, which are fundamental to the ECDSA algorithm used in modern digital signatures.

In addition to these asymmetric algorithms, symmetric encryption like AES 256 is used to protect documents stored in the cloud. AES 256 divides data into blocks and scrambles them using a 256-bit key, making unauthorized decryption virtually impossible with current technology.

Securing Signatures During Transmission

When you sign a document electronically, your signature and the document data travel across the internet. To prevent interception or tampering, SignNow uses Transport Layer Security (TLS), which encrypts all data in transit. This means that even if someone were to intercept the data, they would only see unreadable ciphertext, not your actual signature or document content. The use of multiple encryption algorithms ensures compatibility with different browsers and devices, while maintaining the highest level of security. This approach protects your sensitive information from hackers and cybercriminals, giving you peace of mind every time you sign online.

Protecting Signed Documents in Cloud Storage

After a document is signed, it is often stored in the cloud for easy access and sharing. However, cloud storage introduces new security challenges. SignNow addresses these by storing documents on secure AWS S3 servers, where each file is encrypted using AES 256. This means that even if someone were to gain unauthorized access to the server, they would not be able to read the contents of your documents without the encryption key. Additionally, the keys themselves are protected using advanced cryptographic methods, adding another layer of defense. This comprehensive approach ensures that your signed documents remain confidential and tamper-proof, both during storage and retrieval.

Legal Validity and Compliance of Electronic Signatures

Security is only part of the equation—electronic signatures must also be legally recognized to be truly effective. SignNow complies with major eSignature laws, including the U.S. ESIGN Act and UETA, as well as international regulations. These laws require that electronic signatures are uniquely linked to the signer, that the signature is attached to the document in a way that any changes are detectable, and that the identity of the signer can be verified. SignNow goes beyond these requirements by offering dual-factor authentication, digital certificates, and detailed audit trails, making its signatures not only secure but also court-admissible. This legal compliance gives businesses and individuals the confidence to use eSignatures for contracts, agreements, and other critical documents.

Potential Threats and How SignNow Mitigates Them

While electronic signatures are highly secure, cyber threats are constantly evolving. Potential risks include phishing attacks, unauthorized access, and attempts to forge or alter signed documents. SignNow proactively addresses these threats with a suite of advanced security features:

• Dual-factor authentication ensures that only authorized users can access and sign documents.
• Advanced Threat Protection (ATP) blocks malware, phishing attempts, and malicious links within documents.
• Digital certificates verify the authenticity of each signature and alert users to any tampering.
• Court-admissible audit trails provide a detailed record of every action taken on a document, making it easy to detect and prove any unauthorized changes.

By combining these measures with robust encryption and secure storage, SignNow creates a multi-layered defense that keeps your eSignatures safe from even the most sophisticated attacks.

Best Practices for Keeping Your eSignatures Secure

While SignNow provides industry-leading security, users also play a crucial role in protecting their digital identities. Here are some best practices to maximize your eSignature security:

• Always use strong, unique passwords for your accounts and change them regularly.
• Enable two-factor authentication wherever possible to add an extra layer of protection.
• Be cautious when accessing documents over public Wi-Fi networks—use a VPN if necessary.
• Regularly monitor your account activity and report any suspicious behavior immediately.
• Educate yourself and your team about common phishing tactics and how to avoid them.

By following these guidelines and leveraging SignNow's built-in security features, you can ensure that your electronic signatures remain private, authentic, and legally binding.

Frequently Asked Questions

Ready to experience secure, legally binding electronic signatures? Explore SignNow's plans and discover how easy and safe it is to sign documents online. For developers, you can try the SignNow API for free and build your own secure eSignature integration.

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