Deep cold storage for long-term security

Full network and physical isolation

Sygnum’s deep cold storage is built to protect long-term digital asset holdings today and stay ready for future security needs.

 

Powered by Sygnum Cryo, our deep cold key management technology, private keys are stored in a fully offline, physically isolated environment. The system is designed to evolve with security standards, including post-quantum cryptography. 

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Why Sygnum cold storage

Sygnum’s cold storage builds on traditional cold storage by providing full separation from connected systems while remaining ready for evolving security needs. At Sygnum, cold storage is defined by one principle: full network and physical isolation at all times. Built on Sygnum Cryo, private keys are kept in a physically isolated, fully air-gapped environment, with structured governance and multi-person approval processes. Sygnum Cryo is designed to support evolving security standards, enabling the custody environment to adapt as digital asset infrastructure and blockchains evolve, including considerations around post-quantum cryptography.

What Sygnum cold storage provides

Full offline separation

Assets are held in an environment with no network connectivity, supporting use cases where complete separation from connected systems is required.

Structured and governed access

Asset transfers follow defined approval processes with clear roles and multi-person authorisation, supporting controlled and consistent execution.

Readiness for evolving standards

Sygnum Cryo is designed to adapt as digital asset infrastructure evolves, including post-quantum requirements.

How Sygnum Cryo creates full key isolation

Sygnum Cryo is our proprietary technology for deep cold key management. It reflects an advanced approach to key isolation, combining offline separation, physical protection and governed control into one integrated environment.

Offline key environment

Key material is generated and maintained in a fully air-gapped environment.

Physical isolation

Key material is stored in a dedicated high-security facility with controlled access and layered security controls.

Structural separation

Digital assets are held independently from trading and liquidity infrastructure.

Governed transaction control

Asset movement follows defined multi-person approval procedures.

Swiss-regulated framework

Custody operates within Sygnum’s Swiss-regulated banking environment.

Audited and regulated cold storage

Halborn, a recognised blockchain security firm, has independently reviewed Sygnum’s cold storage environment. This is complemented by regular penetration testing, supporting its integrity.

Sygnum’s custody platform operates within a Swiss-regulated banking framework and is supported by established control and compliance standards:  

  • Isae3000

    Custody processes audited under ISAE 3000 and ISAE 3402 by PwC

  • Fips140

    Hardware protection through FIPS 140-2 Level 3 HSMs

  • research

    Digital asset transactions screened using Crypto-AML controls

  • Bespoke research

    Client assets held off-balance sheet in accordance with Swiss banking law

These controls are designed to support secure key management, transaction processing and regulatory compliance.

Sygnum Cryo

Powered by Sygnum Cryo, our deep cold key management technology, private keys are stored in a fully offline, physically isolated environment.

Contact us Download the factsheet

Local restrictions – Provision of cross-border services

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This website and the information contained herein are addressed solely to persons residing or domiciled in Switzerland.

Sygnum is a regulated bank supervised by the Swiss Market Financial Authority (FINMA). The products and services on this website are authorised in Switzerland. Sygnum cannot promote its products and services in other countries where it is not authorised by the supervisory authority of that country to do so.

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Investor qualification

The following content is available to qualified investors. Please confirm your details below to visit this page, or please see our other digital asset updates here.

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Disclaimer:

The information in this publication pertaining to Sygnum Bank AG (“Sygnum”) is for general information purposes only, as per date of publication, and should not be considered exhaustive. This publication does not consider the financial situation of any natural or legal person, nor does it provide any tax, legal or investment advice. This publication does not constitute any advice or recommendation, an offer or invitation by or on behalf of Sygnum to purchase or sell any assets. No elements of precontractual or contractual relationship are intended. While the information is believed to be from accurate and reliable sources, Sygnum makes no representation or warranties, expressed or implied, as to the accuracy of the information. Sygnum expressly disclaims any and all liability that may be based on such information, omissions, or errors thereof. Any statements contained in this publication attributed to a third party represent Sygnum‘s interpretation of the data, information and/or opinions provided by that third party either publicly or through a subscription service, and such use and interpretation have not been reviewed by the third party. Sygnum reserves the right to amend or replace the information, in part or entirely, at any time, and without any obligation to notify the recipient of such amendment / replacement or to provide the recipient with access to the information. Simultaneously, there is no obligation of Sygnum to inform recipients of information, if before provided information later becomes outdated, inaccurate or obsolete, unless otherwise provided by applicable law. The information provided is not intended for use by or distributed to any individual or legal entity in any jurisdiction or country where such distribution, publication or use would be contrary to the law or regulatory provisions or in which Sygnum does not hold the necessary registration, approval authorization or license. Except as otherwise provided by Sygnum, it is not allowed to modify, copy, distribute or reproduce, display, license, or otherwise use any content for commercial purposes.

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