CRY · Cryptography and Key Management
CRY-04 Protection of Data for Transmission (Transport Protection)
Changed since C5:2020 · formerly CRY-02
Basic criterion
Replaced requirement for strong encryption and authentication with requirement for state of the art encryption and authentication.
Added requirement regarding the protection of remote access communication.
Additional criterion
Replaced requirement for strong encryption and authentication with requirement for state of the art encryption and authentication.
Wording in C5:2020
Basic criterion
The Cloud Service Provider has established procedures and technical measures for strong encryption and authentication for the transmission of data of cloud customers over public networks.
Additional criterion
The Cloud Service Provider has established procedures and technical measures for strong encryption and authentication for the transmission of all data.
Supplementary information on all sub-criteria
When transmitting data with normal protection needs within the cloud service provider's infrastructure, encryption is not mandatory provided that the data is not transmitted via public networks. In this case, the non-public environment of the cloud service provider can generally be deemed trusted. Configuration of the TLS protocol should comply with the recommendations of the (current) version of the BSI Technical Guideline TR-02102-2 'Cryptographic Procedures: Recommendations and key lengths. Part 2 - Use of Transport Layer Security (TLS)'. Cipher Suites should provide Perfect Forward Secrecy. Generally, wildcard certificates should not be used.
Basic criterion
The cloud service provider has established procedures and technical safeguards for state of the art encryption and authentication for the transmission of cloud service customer data and cloud service derived data over public networks.
During remote access to the production environment, the cloud service provider uses state of the art cryptographic mechanisms, including personnel authentication, to protect the communication.
Additional criterion
CRY-04.01AS
Additional, sharpens01BThe cloud service provider has established procedures and technical safeguards for state of the art encryption and authentication for the transmission of all data.
Complementary customer criteria
What cloud service customers implement on their side.
Cloud service customers ensure with suitable controls for those parts of the cloud service under their responsibility that their data is transmitted over encrypted connections in accordance with the respective protection needs.
Related criteria
BSI text from C5:2026 and its changelog: © Federal Office for Information Security 2026, reproduced unchanged under CC BY-ND 4.0. Unofficial site, not affiliated with BSI. Licence and sources