Industry body standardizes a secure channel to optimize security for mobile applications

GlobalPlatform has published an upgrade to its Card Specification v2.2 to protect the data exchange between a secure element (SE) and a trusted execution environment (TEE) on a mobile device. The ‘GlobalPlatform Secure Channel Protocol 11’ addresses the increasing number of use cases, such as mobile banking, where applications utilize both the SE and TEE to protect a secure service. The document is particularly relevant to secure application developers and issuers, and can be downloaded free of charge.

“This advancement focuses on making the best use of security that is already present on the device,” comments Karl Eglof Hartel, Chair of the GlobalPlatform Card Committee and Director for Standards and Innovation in the Mobile Security business unit at Giesecke & Devrient. “Data breaches are growing daily and as more secure services are deployed to mobile devices, hackers will follow. This update seeks to better combine the security characteristics of the SE and TEE, ensuring that the communication channel between them is secure.”

In use cases like biometric authentication, virtual private networks (VPN) or mobile banking, the SE in the device is used to store the critical part of the application and its associated cryptographic keys. In parallel, the trusted application resides in the TEE to enable management of the end user and backend interaction prior to a transaction being authorized. The Secure Channel Protocol 11 protects the data being transferred between these two secure components.  

“The combination of advanced cryptography and the secure components simplifies the delivery of secure services,” adds Karl Eglof. “Data is secure while stored in the SE and TEE, and this channel further strengthens the protection of sensitive data when it is in transit. We have brought forward this update to answer a market need for more effective security and to support the long-term requirements of secure application developers and issuers.”

From a technical perspective, data passed between trusted applications stored in the TEE and SE is protected by the secure channel, which is established by GlobalPlatform’s TEE SE API. Elliptic curve cryptography (ECC) is used for the generation of the session keys for encryption and authentication. It also provides perfect forward secrecy (PFS) by using ephemeral keys, preventing the decryption of the data by attackers, should they also get hold of the long-term keys.