Cryptomathic Blog

The PCI Council requires most actors of payment networks to implement ANSI X9.24/TR-31-compliant key blocks to wrap and securely transmit, transfer, or translate key or PIN codes.

IBM’s mainframe computers have been a rock-steady part of banks’ security infrastructure for many years. Originating from the local data-center concept, the current release is able to stretch banks’ security architecture across the hybrid cloud, harnessing advantages of on-premise and cloud-native software deployments - all without compromising data security and privacy.

Invented by Mohamed Atalla, the Atalla key block is the root of all key blocks. All over the globe, hundreds of millions of financial transactions are secured daily using hardware security modules (HSMs) and the Atalla key block format that follows TR-31 guidelines. Here we will explain a bit about AKB and why a banking-grade key management system (KMS) must support it.

Key distribution is perhaps the most important and crucial aspect of the ANSI X9.24-1-2017 part 1 standard. But first, let us explain what cryptographic key distribution is.

Key Blocks have been invented as a standard way for protecting the integrity of symmetric cryptographic keys and for identifying what the keys can be used for. Key Blocks are used to protect Triple-DES keys (Key Blocks can be used as 3DES key bundles), but also AES keys (often using AES key wrapping).

In June 2019, the PCI Security Standards Council issued an information supplement titled PCI PIN Security Requirement 18-3 – Key Blocks, which requires that encrypted symmetric keys be managed in structures called “Key Blocks.”