How can i decrypt saml response in one login from private key?

I am working saml integration, which works fine for me, i did secure saml response, for that i am using public and private key, i am getting encrypted saml response, i want to decrypt it by private key, for demo purpose i am using onelogin developer account, they given attribute extractor from this link

https://developers.onelogin.com/saml/online-tools/attribute-extractor

which works fine for me, i want to do this programmatically, but still not able to find function for it, can anyone have idea how to decrypt it programmatically ?

via Chebli Mohamed