FFIEC IT Examination Handbook InfoBase – Encryption

Action Summary

Financial institutions should employ encryption to mitigate the risk of disclosure or alteration of sensitive information in storage and transit.Encryption implementations should include

Encryption is used to secure communications and data storage, particularly authentication credentials and the transmission of sensitive information. It can be used throughout a technological environment, including the operating systems, middleware, applications, file systems, and communications protocols.

Encryption can be used as a preventive control, a detective control, or both. As a prevention control, encryption acts to protect data from disclosure to unauthorized parties. As a detective control, encryption is used to allow discovery of unauthorized changes to data and to assign responsibility for data among authorized parties. When prevention and detection are joined, encryption is a key control in ensuring confidentiality, data integrity, and accountability.

Properly used, encryption can strengthen the security of an institution's systems. Encryption also has the potential, however, to weaken other security aspects. For instance, encrypted data drastically lessens the effectiveness of any security mechanism that relies on inspections of the data, such as anti-virus scanning and intrusion detection systems. When encrypted communications are used, networks may have to be reconfigured to allow for adequate detection of malicious code and system intrusions.

Although necessary, encryption carries the risk of making data unavailable should anything go wrong with data handling, key management, or the actual encryption. For example, a loss of encryption keys or other failures in the encryption process can deny the institution access to the encrypted data. The products used and administrative controls should contain robust and effective controls to ensure reliability.

Financial institutions should employ an encryption strength sufficient to protect information from disclosure until such time as the information's disclosure poses no material threat. For instance, authenticators should be encrypted at a strength sufficient to allow the institution time to detect and react to an authenticator theft before the attacker can decrypt the stolen authenticators.

Decisions regarding what data to encrypt and at what points to encrypt the data are typically based on the risk of disclosure and the costs and risks of encryption. The costs include potentially significant overhead costs on hosts and networks. Generally speaking, authenticators are encrypted whether on public networks or on the financial institution's network. Sensitive information is also encrypted when passing over a public network and also may be encrypted within the institution.

Encryption cannot guarantee data security. Even if encryption is properly implemented, for example, a security breach at one of the endpoints of the communication can be used to steal the data or allow an intruder to masquerade as a legitimate system user.

More:
FFIEC IT Examination Handbook InfoBase - Encryption