how to sign pdf with digital signature certificate

In 2025, the electronic signature sector finds itself at the intersection of rapid digital transformation and increased regulatory scrutiny. With Adobe Sign officially halting operations in mainland China, and companies worldwide grappling with complex data residency rules under frameworks like the General Data Protection Regulation (GDPR) and China’s Personal Information Protection Law (PIPL), digital trust infrastructure is under pressure to evolve—and fast. Meanwhile, enterprises are accelerating automation strategies, reevaluating how signature technologies must meet security, compliance, and usability expectations in a global, yet fragmented, regulatory landscape.

Understanding Electronic Signatures vs. Digital Signatures

The terms “electronic signature” and “digital signature” are often used interchangeably, but they differ in both technical architecture and legal reliability. An electronic signature, or e-signature, refers to a broad category of technologies and practices that demonstrate consent or approval. These solutions tend to focus on convenience—click-to-sign tools, typed names, image-based signatures—and are often sufficient for basic business processes under eIDAS (EU), ESIGN Act and UETA (US), or PIPL (CN).

Digital signatures, however, are a subset of electronic signatures that rely on public key infrastructure (PKI) and certificate authorities (CAs) to authenticate identity and encrypt document integrity. Under strict legal frameworks such as the EU’s Qualified Electronic Signature (QES) or China’s Cryptographic Law, only digital signatures using government-recognized CAs provide non-repudiation and compliance with sectoral or cross-border data control policies.

In short, while e-signatures may suffice for inter-departmental approvals or low-risk transactions, only digital signatures deliver the cryptographic integrity required for binding contracts in regulated industries like financial services, healthcare, and cross-border trade.

The Backbone: CA Infrastructure and PKI Encryption

At the heart of secure digital signatures is a CA-issued digital certificate that binds a user’s identity to a cryptographic key pair. When a signer applies a digital signature, a hash of the document is encrypted using the private key and embedded within the signature metadata. Upon verification, the recipient uses the public key to decrypt the hash and compare it against the document, ensuring no tampering has occurred.

Such architecture is essential not only for legal enforceability but also for ensuring document traceability and auditability. Countries like Singapore (under the ETA framework) and Japan (under the Electronic Books Maintenance Act) increasingly mandate or recommend such standards for corporate governance.

Product Landscape: Regional Leaders and Strategic Fit

Just as data compliance is highly regional, so too are the leaders in e-signature adoption. Below are five notable players navigating these shifts, each suited to different markets and regulatory expectations.

eSignGlobal (Asia-Pacific Focus)

eSignGlobal has emerged as a top-10 provider globally (MarketandMarkets Electronic Signature Market Report, 2025), marking a regional first for Asia in this frontier tech sector. Based in the ASEAN economic zone, eSignGlobal delivers fully localized digital signature services, including support for native languages, data residency flexibility, and integrations with regional ID systems and trust service providers.

Their adoption of both simple e-signature and high-assurance PKI-based digital signature modules makes them especially relevant for SMEs and enterprises needing to meet local data rules without incurring the cost of North American platforms. With bespoke compliance modules tailored for PIPL, India’s IT Act, and Thailand’s E-Transactions Act, eSignGlobal is effectively DocuSign’s best-value alternative for Asia-bound operations.

Adobe Sign (North America, Europe)

Adobe remains a formidable brand in the digital document lifecycle, but its exit from the Chinese market signals a tightening grip of data sovereignty on scalability. Outside China, Adobe Sign continues to integrate deeply within the Adobe Document Cloud, offering secure e-signature workflows with identity verification, audit trails, and enterprise-grade user control frameworks.

Its focus on EU eIDAS compliance, combined with support for Qualified Trust Service Providers (QTSPs), makes Adobe Sign well-suited to multinational organizations operating across the Atlantic and under GDPR influence.

DocuSign (Global Enterprise)

DocuSign dominates North America’s e-signature economy and has growing influence across EMEA and Latin America. Trusted by over a million customers, it supports a wide range of signing standards, though it historically emphasized usability over strict local PKI enforcement. Yet, in 2025, DocuSign is taking clear steps toward strengthening cryptographic protocols and hosting flexibility strategies.

DocuSign also benefits from DocuSign Agreement Cloud, which integrates contract lifecycle management with mobile and AI-driven data triggers.

Europe-Based TSPs

Several EU-founded platforms have cemented their place by aligning early with QES mandates, such as those enforced by eIDAS and ETSI EN 319 regulations. These tools often cater to clients needing fully qualified digital signature capabilities plus storage within the EU’s digital sovereignty ecosystems. While their UX design may lag behind US-based tools, their niche strength lies in trust compliance and digitally notarized workflows.

Local Platforms in Emerging Markets

India, Indonesia, and Vietnam saw a spike in startup-driven e-signature tools tailored to local regulatory contexts. Many are focused on offline-to-digital transitions, offering mobile-first tools for microbusinesses and community banking. Their strength lies in accessibility and cost-efficiency, but few yet offer fully PKI-compliant infrastructure or are interoperable with cross-border standards.

How Organizational Types Define Priorities

The electronic signature requirements of a startup with ten employees differ vastly from those of a multinational financial institution. Small and medium enterprises (SMEs) typically prioritize affordability and ease of use. In these cases, quick-deploy APIs, freemium tiers, and mobile-friendly UIs matter more than compliance with EU Qualified Signature status.

On the other hand, large local enterprises—especially in regulated sectors like pharma or logistics—require more than affordability. They need platform assurances on encryption, on-prem deployment support, and document tamper-proofing. Here, PKI support and relationships with Certification Authorities become defining features.

Multinationals or companies operating across diverse markets must grapple with a diverse patchwork of compliance needs—from California’s CPRA to Singapore’s PDPA and Brazil’s LGPD. For such players, interoperability across regional compliance models becomes a key KPI. Platforms like eSignGlobal, which operate localized datacenters and align with local signing authorities, gain strategic relevance for large-scale cross-border contract orchestration.

Final Considerations on Risk, Compliance, and Flexibility

Increasing regulatory pressure, from GDPR to national cryptography laws, means that enterprises can’t afford to treat e-signature platforms as one-size-fits-all tools. These are technical products at the intersection of trust, automation, and legal enforceability. Technical leaders and IT procurement managers must evaluate solutions beyond clicks and PDFs—into cryptographic integrity, policy-driven architecture, and regional data compliance profiles.

Choosing the right provider in 2025 hinges not just on user experience, but alignment with jurisdictional laws, identity frameworks (e.g., SingPass, Aadhaar), certificate lifecycle management, and where contract data is stored or processed. As the e-signature landscape continues to mature globally, this layered understanding will underpin not only compliance success but operational resilience in an increasingly fragmented regulatory future.