What is Digital signature?

A digital signature is a cryptographic technique used to authenticate the identity of the sender of a message or document and to ensure that the content has not been altered during transmission. It provides the highest level of security and is commonly used for online transactions, legal agreements, and official documents. In Switzerland, digital signatures are legally recognized and are governed by the Federal Act on Electronic Signatures (ZertES), aligning with European regulations such as the eIDAS Regulation.

Key Features of a Digital Signature

Authentication: A digital signature verifies the identity of the signer. It works similarly to a handwritten signature but uses encryption to ensure that the document comes from the claimed sender.
Integrity: Digital signatures ensure the integrity of the signed document. Any alteration to the document after signing will invalidate the signature, providing proof that the document has not been tampered with.
Non-repudiation: Since digital signatures are uniquely tied to the signer, they provide non-repudiation, meaning the signer cannot deny having signed the document. This feature is crucial in legal and contractual situations.

How Digital Signatures Work

A digital signature relies on asymmetric cryptography, involving two keys:

Private Key: The private key is kept secret by the signer and is used to create the signature.
Public Key: The public key is shared with recipients and used to verify the signature.

When a document is signed digitally, the private key is used to encrypt a hash value of the document. The recipient then uses the public key to decrypt the hash value and compare it to the hash value of the document they received. If they match, the document is verified as authentic and unchanged.

Legal Framework for Digital Signatures in Switzerland

In Switzerland, digital signatures are recognized under the Federal Act on Electronic Signatures (ZertES). This law ensures that digital signatures have the same legal standing as traditional handwritten signatures, provided they meet certain security requirements. Digital signatures in Switzerland can be classified into three categories:

Simple Digital Signatures: Basic level of security and verification.
Advanced Digital Signatures: Provide stronger security and are more commonly used for legal and contractual documents.
Qualified Digital Signatures: The highest level of digital signature, equivalent to a handwritten signature, and subject to strict regulations and verification by accredited providers.

Digital signatures are also aligned with the European Union’s eIDAS Regulation, which ensures that cross-border transactions within the EU and Switzerland can be securely and legally signed using digital signatures.

Benefits of Digital Signatures

Efficiency: Digital signatures allow for faster transactions and approvals without the need for physical signatures, speeding up business processes and reducing paperwork.
Security: Digital signatures provide a high level of security by ensuring the authenticity of documents and protecting against tampering.
Cost Savings: By eliminating the need for physical document handling, postage, and storage, digital signatures reduce operational costs.
Global Recognition: Digital signatures recognized by accredited providers are legally binding in Switzerland and across many countries, facilitating international transactions and agreements.

In Switzerland, digital signatures offer businesses and individuals a secure, efficient, and legally recognized method for signing documents, ensuring that digital transactions and agreements are both valid and secure.