Why am I unable to use the hash_hmac function in PHP on the Customer Portal or custom scripts?
PHP, Connect PHP
Oracle Service Cloud (OSvC), All Supported versions
The hash_hmac function is part of the "Hash" cryptography extension in PHP. This extension is not enabled in Oracle Service Cloud and cannot be enabled. As an alternative, customers should consider using the Crypto API included in Connect PHP. Additional information about the Crypto API can be found by searching for "crypto" in the ConnectPHP documentation:
Answer ID 5169: Technical Documentation and Sample Code
Another alternative would be to send the data to an external server and using the hash_hmac function there.