lib/Middleware/DigestAuthMiddleware.php
private function setAlgorithm(string $algorithm): void
    {
        if (('MD5' == $algorithm) || ('MD5-sess' == $algorithm)) {
            $this->algorithm = $algorithm;
        } else {
            throw new \InvalidArgumentException('DigestAuthMiddleware: Only MD5 and MD5-sess algorithms are currently supported.');
        }
    }
private function setAlgorithm(string $algorithm): void
    {
        if (('MD5' == $algorithm) || ('MD5-sess' == $algorithm)) {
            $this->algorithm = $algorithm;
        } else {
            throw new \InvalidArgumentException('DigestAuthMiddleware: Only MD5 and MD5-sess algorithms are currently supported.');
        }
    }
Sets the hashing algorithm to be used. Currently only uses MD5 specified by either MD5 or MD5-sess.
RFCs are currently in draft stage for the proposal of SHA-256 and SHA-512-256.
Support will be added once the RFC leaves the draft stage.

@param string $algorithm the algorithm the server has requested to use

@throws \InvalidArgumentException if $algorithm is set to anything other than MD5 or MD5-sess