The Common Criteria assurance process is a means of gaining confidence that a product is designed correctly to ensure security threats have been addressed. Certified products are allocated an Evaluation Assurance Level from 1-6, with 6 being the most stringent. For the majority of police information, security products with EAL4 are advantageous.
There are a number of countries that have mutual recognition of evaluation facilities and so a product evaluated by an approved facility in one country will be accepted by the national authority in another.
Commercial Product Assurance (CPA) is a CESG scheme to validate commercial products as being fit for purpose in protecting HMG assets.
CESG Assisted Products (CAPS) is a way of ensuring quality of cryptography in high end products.