message digests and modulus sizes supported in free radius

Hi, Can anybody please tell me which standard does free radius supports for signature generation and signature verification? I mean, there are standards like (1) PKCS1_V1_5 (2) PSS (3) ANSIX9.31 Which standard does free radius support? I have one more doubt on type of message digest algorithms and modulus sizes supported in free radius. I generated certificates with sha1 and with modulus size 1024. This is working fine. I want to know if it works with other message digests like sha224, sha256, sha384, sha512 and modulus sizes like 1536, 2048, 3072, 4096. Please help me in this regard. thanks in advance, Jagadish