Virifi’s Solution Proposal supports flexible signature workflows to meet a range of collaboration and compliance needs. These workflows include:
Single Signature – One signer
Parallel Signatures – Multiple signers independently
Sequential Signatures – Signers in a defined order
Each mode is implemented in line with the ETSI eIDAS specifications, and mode availability may vary based on the signature format used (PAdES, XAdES, JAdES, CAdES).
Single Signature Mode
Definition: One signer signs the document or payload.
Availability: Supported across all formats (PAdES, XAdES, JAdES, CAdES).
Use Cases: Personal approvals, internal transactions, digital signing portals.
Parallel Signatures Mode
Definition: Multiple signers sign the same document independently and simultaneously. Each signature is treated as individually valid.
Format Compatibility:
✅ XAdES (XML supports multiple <Signature> elements)
✅ JAdES (JSON allows multiple signatures via array structure)
✅ CAdES (CMS allows multiple signers in a single container)
❌ Not supported in PAdES due to limitations in the PDF structure and Adobe validation models
Use Cases: Committee approvals, collaborative documents, API-level co-signatures.
Sequential Signatures Mode
Definition: Signers sign the document in a specific order, with each signature applied after the previous one.
Format Compatibility:
✅ PAdES (Sequential signatures are fully supported via incremental updates)
✅ XAdES (Supports order-preserving multiple <Signature> elements)
✅ JAdES (Supports ordered multi-signature application)
✅ CAdES (Handles nested and sequential signer info)
Use Cases: Approval chains, legal workflows, tiered authorization.
ETSI Compliance Notes
ETSI EN 319 142-1 (PAdES) only supports sequential multi-signatures. Attempting parallel signatures may break signature validation in tools like Adobe Acrobat.
ETSI EN 319 132-1 (XAdES) and ETSI TS 119 182-1 (JAdES) allow both parallel and sequential signing models via structural flexibility.
ETSI EN 319 122-1 (CAdES) permits either model based on signer encapsulation.
How It Works in Virifi’s Solution Proposal
Signature modes are defined per request using:
Signing workflow definitions
Signer role assignments
API support for signature flow chaining or parallelization
Backends and demo applications are capable of:
Merging signatures appropriately by format
Validating each signer in real-time or post-submission