src/Amadeus/Client/Session/Handler/SoapHeader4.php
protected function generatePasswordDigest($password, $creationString, $messageNonce)
    {
        return base64_encode(sha1($messageNonce . $creationString . sha1($password, true), true));
    }
protected function generatePasswordDigest($password, $creationString, $messageNonce)
    {
        return base64_encode(sha1($messageNonce . $creationString . sha1($password, true), true));
    }
Generates a Password Digest following this algorithm:
HashedPassword = Base64(SHA-1( nonce + created + SHA-1 ( password )))
as defined in
https://webservices.amadeus.com/extranet/kdbViewDocument.do?externalId=wikidoc_web_services_embedded_security_implementation_guide_header_entries_ws-security_usernametoken&docStatus=Published&mpId=fla__1__technical

EXAMPLE: with:
Nonce in Base 64 = 'PZgFvh5439plJpKpIyf5ucmXhNU='
Timestamp = '2013-01-11T09:41:03Z'
Clear Password = 'WBSPassword'
The digest algorithm returns the Encrypted Password in Base 64:
HshPwd = 'ic3AOJElVpvkz9ZBKd105Siry28='

@param string $password CLEARTEXT password (NOT the base64 encoded password used in Security_Authenticate)
@param string $creationString message creation datetime
UTC Format: yyyy-mm-ddTHH:MM:SSZ or yyyy-mm-ddTHH:MM:SS.sssZ
@param string $messageNonce Random unique string
@return string The generated Password Digest