Document Signing (SolSign)

Trust in agreements today is mediated by centralized SaaS platforms like DocuSign or Adobe Sign. While these services are convenient, they rely on closed databases, proprietary formats, and a “trust-us” audit trail. A signature is as good as the company’s servers and uptime. Revocations, disputes, and version history remain subject to corporate control, not cryptographic guarantees.

SolMail introduces SolSign: a protocol-native signing layer that makes agreements cryptographic, verifiable, and composable with the same inbox-first UX. Just as SolMail merges messaging and settlement into one surface, SolSign merges communication and formal attestation.

Architecture

Use Case: Signing as a First-Class Primitive

SolSign enables the Web3-native equivalent of DocuSign, but with far stronger guarantees:

• Approvals & Agreements: Any PDF, plain text contract, or structured payload can be attached and circulated within a SolMail thread for signature.

• Multi-Signature Workflows: DAO constitutions, treasury disbursements, or corporate resolutions can require multiple signers in ordered or parallel workflows.

• Role-Based Controls: Enterprises can enforce signature rules tied to organizational roles (e.g., CFO must co-sign invoices over $50k).

In short: every SolMail thread can become a contract space, with cryptographic enforcement and programmable logic.

Content Hashing: Canonical Proof of What Was Signed

The problem with Web2 signing is ambiguity: what exactly was signed? Was the PDF altered before or after?

SolSign enforces canonicalization:

• Every document is hashed into a SHA-256 digest, ensuring content immutability.

• Hashes are timestamped on-chain to create an independent proof of existence and sequence.

• Signer sets are explicitly bound to the digest, ensuring that signatures apply only to the unaltered version.

This guarantees that what is signed today is exactly what is provable tomorrow, in any jurisdiction or dispute.

Attestations: Beyond a Scribble on a File

SolSign treats signatures as on-chain attestations, not merely “images pasted on PDFs.”

• Ed25519 signatures ensure cryptographic binding between signer identity and content.

• On-chain attestations create a permanent, timestamped record of who signed and when.

• Revocation mechanisms allow signers to invalidate their own attestations with proper key proof.

• Versioning support enables iterative drafts, with hash-linked lineage from draft → signed version → amended version.

• Immutable audit trails allow any observer to verify the integrity of the process without trusting a vendor’s database.

The result: signatures are not just marks on a file, but provable facts embedded into the ledger of communication.

Enterprise Hooks: From Compliance to Longevity

Enterprises and DAOs require more than signatures; they require governance, retention, and auditability. SolSign extends signing into an enterprise-grade primitive:

• Legal Hold Policies: Organizations can cryptographically lock documents from deletion once under investigation.

• Retention Rules: Signed agreements can be automatically retained for 7, 10, or more years, with cryptographic proofs of continuity.

• Exportable Proofs: Signatures and hashes can be exported in verifiable bundles, enabling use in legal proceedings or migration across systems.

• Audit Trails: Every action — draft creation, signature, revocation, amendment — is logged immutably, providing compliance-ready evidence for regulators and courts.

These features make SolSign suitable for both grassroots DAOs and global enterprises, serving as the DocuSign of Solana, but without the gatekeepers or single points of failure.