It seems that OIOSAML only supports CSP (CryptoAPI / Cryptographic Service Provider) certificates, but Microsoft have started using/supporting CNG (Cryptography Next Generation) certificates which our customers have started to use.
I cannot say what actually happens when using a CNG to sign/verify SAML messages in OIOSAML since I only have this as a report from our customers.
It seems that OIOSAML only supports CSP (CryptoAPI / Cryptographic Service Provider) certificates, but Microsoft have started using/supporting CNG (Cryptography Next Generation) certificates which our customers have started to use.
I cannot say what actually happens when using a CNG to sign/verify SAML messages in OIOSAML since I only have this as a report from our customers.