Thanks a lot for the suggestions given, and I went throught them. I just thought of implementing the thing in the following manner, basically applying PKI system 2 times.
1. The person will apply hash to his bid value.
2. Then he will apply private key and will send public key to the receiver.
3. The reciever would apply his private key and send the public key to the bidder,i.e. the person who sent the bid.
4. the value would be stored in database, and would apply the security feature of database to limit the access to the data.
5. When the bid would open on the day, the reciever would apply the key to decipher from his end. Then the sender would apply the key to get the original data.
Need your feedback on this.
Thanks in advance,
Rudra