OPEN SYMMETRIC KEY NameOfSymmetricKey
         DECRYPTION BY CERTIFICATE NameOfCertificate;

         Select EncryptDOB,  ISNULL(CONVERT(VARCHAR    (MAX),DecryptByKeyAutoCert    (cert_ID('NameOfCertificate'), NULL,     EncryptDOB)),'1900-01-01') As 'DateOfBirth'
  from TableName

  CLOSE SYMMETRIC KEY NameOfSymmetricKey;