Implement PKI - What I need?

[Timothy]

Hi, I would like to implement a PKI interacted application which requires:

1, Retrieve Public key from a open Public Key Directory Server (LDAP)
2, Encrypt/Decrypt message
3, Digitially sign message
4, Verify the digitial signature
5, Verify Signer certificate with CRLs
6, Package signed message in PKCS #7 format
7, Able to read PKCS #12 key stores, both Netscape(.p12) and I.E.(.pfx) format.

Which libraries should I have in order to implement the above features?

Thank you..