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FPSF-CPP-001 — Overview

Layer: Overview · Audience: executives, regulators, institutional evaluators For normative requirements, see the Formal Specification.

The Problem​

Digital payments today record every party in every transaction at every step. The sender, the receiver, the amount, and the timestamp are captured by intermediaries — by design, for fraud prevention and regulatory compliance. This eliminates the practical privacy that people have long exercised with physical cash.

Physical cash allows someone to pass value to another person without that transfer being recorded by a bank, a network, or a government. Each participant in the chain is visible only to the person immediately before and after them. No central record connects the two.

No digital equivalent exists at scale today. Blockchain systems introduced bearer-like properties but brought public ledgers, volatility, and regulatory friction. Account-based digital money is entirely trackable. The CashPack Protocol fills this gap.

The Solution​

The CashPack Protocol defines a signed, transferable digital instrument — the cash-pack — that can be passed from person to person without each transfer being recorded by the Operator.

An identified account holder (the Principal) asks a licensed Operator to lock a specific amount and issue a cash-pack addressed to a recipient identified only by a public key. That recipient can pass it to the next person, who can pass it to the next, each time asking the Operator to update the bearer field. The Operator countersigns every update. The final holder redeems it.

The Operator sees who locked the funds and who redeemed them. The intermediate chain is visible only to its participants.

This is structurally analogous to how physical cash works — with three significant improvements: cryptographic verification at every step, a tamper-evident audit trail available to authorized investigators, and no physical transport risk.

Infrastructure Agnosticism​

The CashPack Protocol is a behavioral standard. It defines data structures, cryptographic rules, and protocol flows. It does not mandate any particular settlement or record-keeping infrastructure.

Settlement LayerCompatibility
Traditional core bankingFully supported. The Operator's internal ledger records the lock and the redemption.
Tokenized depositsFully supported. The locked amount can be a tokenized deposit; the cash-pack is the bearer wrapper.
Permissioned distributed ledgerFully supported.
Public blockchainSupported as a settlement layer for Operators who choose it.
Digital securities / bearer bondsThe instrument structure generalizes to any locked value.

Target Use Cases​

  • Person-to-person transfers where sender and receiver prefer not to expose their relationship to the financial system
  • Merchant payments where the payer wants cash-like privacy at point of sale
  • Gift instruments, vouchers, and prepaid value that can be freely passed before redemption
  • Tokenized deposit wrappers enabling privacy-preserving transfer of bank money
  • Digital securities and bearer bonds that need to change hands without on-ledger transfers at every hop
  • Cross-border payments (Phase 2: with inter-Operator settlement agreements)

Document Map​

LayerDocumentPurpose
Formal SpecificationSPEC.mdNormative. Data structures, cryptographic rules, protocol obligations.
Overviewthis documentWhat it is and why it exists.
Core ConceptsMental models, bearer principle, privacy model.
GuidesIssuance, renewal, redemption, disposable keys.
GovernanceOperator eligibility, compliance, risk controls.
ReferenceEndpoints, error codes, glossary.
Business ModelRevenue models for Operators.

FPSF-CPP-001 v1.0.0 · Draft · Fabric Payment Standards Foundation · Apache-2.0