It should be noted that the default signature algorithm used by openssl_sign() and openssl_verify (OPENSSL_ALGO_SHA1) is no longer supported by default in OpenSSL Version 3 series.
With an up to date OpenSSL library, one has to run
"update-crypto-policies --set LEGACY"
on the server where the library resides in order to allow these functions to work without the optional alternative algorithm argument.