Dfns is built for institutions: MPC signer nodes in enclaves, velocity limits, sanctions screening, travel-rule integration, and approval groups with quorums. It is the most complete escalation model of the hosted signers. It is also priced and shaped for a compliance team, not for an agent developer.
Dfns for the regulated operating accounts; Coldstar for the cold reserve behind them.
| Coldstar | Dfns | |
|---|---|---|
| Who holds the root key | You. The cold root lives encrypted on your own USB drive. No vendor holds a key, a share, or an account. | Dfns-operated MPC/TSS nodes. The security page does not disclose the threshold or whether customers hold a share. "Break-the-glass" key export is offered. Delegated (end-user) wallets bypass the policy engine entirely. |
| Where the key lives | On your machine. The air-gapped root signs a bounded policy envelope; a disposable session key signs routine transactions inside it. | MPC signer nodes inside AWS Nitro Enclaves; Intel SGX, IBM, Thales HSM, and on-prem options on request. |
| Policy engine | Per-transaction limit, daily cap, program allowlist, recipient allowlist and blocklist, escalate-above threshold. Evaluated locally, first match wins, before any signature exists. | Rules: transaction amount limit (USD and nominal), amount velocity and count velocity per time window, recipient whitelist, Chainalysis and travel-rule screening. Actions: block or request approval. Program- or instruction-level Solana rules not listed. Enforcement at the policy layer; not stated as in-enclave. |
| Out-of-policy transactions | ESCALATE to a human over air-gapped QR, or REJECT. No signature is produced for a rejected transaction. | Held for approval by one or more approval groups, each with its own quorum; all must pass. The strongest escalation model in this set. |
| Cold / offline root | Yes — the root key never touches a networked machine. | No air-gapped root. On-prem and HSM deployments exist for enterprise. |
| Agent integration | Framework-agnostic: the agent proposes an unsigned transaction, the signer decides. CLI signer today; MCP server in progress. | No dedicated agent product or docs found. |
| Solana support | Solana mainnet. Core is chain-agnostic; EVM signing exists. | Yes, including durable nonces. |
| Source & self-hosting | Open source (MIT), self-hosted. No API key, no SaaS dependency, nothing to go down. | Cryptographic libraries donated to the Linux Foundation; service code closed. Hosted or enterprise on-prem. |
| Pricing | Free software plus a ~$10 drive. | Starter $800/year (10 wallets, 100 signatures/month); Basic $8,000/year; Pro $35,000/year; Enterprise custom. No AUM or per-transaction fees. |
| Maturity | Beta — the signing core and policy engine are in scope for the planned independent audit. | Production; SOC 2 Type II (KPMG), ISO 27001; audits by Kudelski, Halborn, Redacted. |
Dfns gets escalation right: real quorums, real velocity limits, real screening. If you need those for regulatory reasons, Coldstar is not a substitute. If you need them because an agent should not be able to drain a wallet, Coldstar gives you the limits and the human gate without the institution.
Dfns runs the signer nodes. Its security page does not say how many shares exist or whether you hold one, and it notes delegated wallets skip the policy engine. For an institution buying a compliant service with contracts and audits behind it, that is a normal arrangement. For a developer trying to bound an agent, it is a lot of surface you do not control.
Coldstar's arrangement is explicit: one ciphertext root on a drive in your possession; local policy with limits, allowlists, and a daily cap; escalation to a human over QR. You can read all of it.
Dfns is production, certified, and audited. Coldstar is beta, pre-audit.
We did not find one on its first-party pages at review time. Its API supports programmatic signing under policy, which an agent could use.
Dfns-operated MPC nodes in enclaves. The threshold and customer share are not disclosed on the security page. Break-the-glass export is offered.
Dfns, for institutional workflows: multi-group quorums. Coldstar has a single escalate-to-human step over QR, which is what a small team actually operates.
Open source, MIT. macOS, Linux, Windows — and on the Solana Seeker dApp Store.
pip install coldstar
Third-party facts were checked against the vendor's own pages on the date above. Pricing and feature sets change; if something here is out of date, tell us and we will fix it.