Hi, We are testing our PKI SDK on MAC 10.6 which includes a TOKEND module to sign and decrypt mails using Mail.app. To support apple’s native applications, we supply a TOKEND module which creates a keychain corresponding to the attached smart card/token. During testing on MAC v10.6, the operation fails while decrypting mails from the apple MAIL application. It says that no valid cert is found in the keychain. In spite of the fact, that there is a valid and trusted certificate is present on the token/smart card. While debugging the tokend module, it is observed that decryption was actually successfully took place on the token but still the MAIL APP failed to decrypt the mail. The following callback function of the tokend module was called upon receiving the decryption request from MAIL APP, *void SFDKeyHandle::decrypt(const Context &context,* * const CssmData &cipher, CssmData &clear)* And the above function executed successfully and returned the decrypted data of length 24 bytes. But the MAIL APP ignored the success result and displayed the error. We also tried to sign a mail and signed mails without any issue. Please let me how can i get this issue resolved? Can some body provide some pointer to find out the cause of this error? Thanks.