Yesterday I gave a talk at DRIVE 2013 on best practices for securing the exchange of sensitive data entitled, “Data Exchange: Transferring Sensitive Data Between Systems.” [pdf]
What follows are my notes and references from the presentation. Anything I’ve missed here will be available in the video, which I’m told will be online via the DRIVE site in March.
Securing Common Methods of Sharing Data
One solution for securing data at rest is GnuPG. However, it can be difficult to provision and manage.
- USB: In general, do not rely on software that comes with USB drives to keep your data secure.
- FTP: Do not use FTP to exchange sensitive data. It can be easily intercepted.
- SFTP: Use public key cryptography when exchanging data with SFTP.
- E-mail: In general, do not trust e-mail as a transport. Use S/MIME to help protect your communications.
- File shares: This is often configured incorrectly. Use a distributed, encrypted file sharing technology like Microsoft EFS. For local encryption consider BitLocker (Windows), File Vault 2 (OS X), dm-crypt (Linux), or TrueCrypt (all).
- IM: Use a mechanism like Off the Record to help you protect communication.
Note that files extracted from encrypted archived may end up unencrypted in your temporary folder. Make sure to securely remove any temporary files left over from extraction from encrypted archives.
Requirements of Solution Providers
Choose a provider that:
- Cannot access your documents and does not escrow your encryption keys.
- Properly disposes of encryption keys, even if the keys are temporary.
- Enables you to specify who can and who cannot view your documents; when and how long they can access your documents.
- Logs document access and can provide you with reports on-demand.
- Allows you to have documents automatically deleted after retrieval by your peer(s) and/or a period of time.
- Securely wipes artifacts when no longer needed: on the cloud and on the desktop. This will require a desktop solution.
- Provides e-mail notification on file access.
- Allows you to specify where data is stored in terms of geographical location.
- Allows you to exchange cryptographic keys with colleagues and verify their identity.
- Allows you to require client-certificate authentication of yourself and persons accessing your documents.
- Offers two-factor authentication.
- Uses industry-standard encryption for data at-rest: AES-256 for encryption; RSA-2048 for signatures; SHA-256 for integrity checks.
- Uses industry-standard encryption for data in-motion: HTTPS, TLS 1.2; 2048-bit SSL certificate
Free Software That Will Securely Wipe Drives and Files
Free Secure E-mail Providers
- Hushmail (Recommended)
- S-Mail
- Comodo SecureEmail