Abstract by anuja a sonalker on Asymmetric Key Distribution

Key distribution 
time (sec)-->
Key size (bits) -->
Effect of Key share reuse on Key distribution time 
with Reuse
without Reuse
Fig 4.6: Effect of key share reuse on key generation.
4.4.1.2 Communication Overheads 
The RMI communication links were generally either 15-16 milliseconds each or 31-32 
milliseconds depending on whether the servers being connected to were remote or 
resident on the same machine. The percentage of time spent in RMI communication was 
more significant as an overhead in the Share Server operations as compared to the key 
generation operations of the Trusted Dealer.
Table 4.4: RMI Communication overheads. 
Run 512 
1024 
2048 
TD 
operations 
Share Server 
Operations 
TD 
operations 
Share Server 
Operations 
TD 
operations 
Share Server 
Operations 
1 
4.6% 24.5% 2.3% 18.0% 1.5% 7.9% 
2 
3.5% 25.0% 1.9% 22.0% 1.2% 7.7% 
3 
3.6% 27.0% 1.9% 15.0% 1.3% 8.2% 
4 
3.8% 26.0% 1.9% 15.8% 1.4% 8.0% 
Avg 
3.88% 25.63% 2.00% 17.70% 1.35% 7.95% 

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48 
 
Communication Overheads
0.00%
5.00%
10.00%
15.00%
20.00%
25.00%
30.00%
512
1024
2048
Key Size (bits)-->
Percentage of Processing time (%)
Share Server RMI
operations
Trusted Dealer RMI
Operations
 
Fig 4.7: RMI Communication Overheads. 
Table 4.4 gives the percentage of time consumed by RMI in the entire Trusted Dealer 
operations and also in the Share Server operations. Here we see that RMI overheads in 
the Trusted Dealer operations reduce in significance though they make still take the same 
amount of time as before or slightly more in passing large data (key shares, crypto 
components, hashes and more) in a serialized form. Since the time taken for key 
generation increases substantially with increase in key size as compared to the increase in 
the time taken for RMI communication, RMI overheads in the Trusted Dealer can be 
considered insignificant. 
In the Share server operation however, RMI communications are large enough to be 
considered significant. Again, when the size of the secret key is as small as 512 bits, the 
RMI overheads seem to look more prominent and account for approximately one fourth 

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49 
of the total execution time of the Trusted Dealer. As the size of the key increases, the 
Trusted Dealer requires more time for the key generation process while the time taken for 
RMI communication still remains almost the same. Thus RMI seems to be a good 
communication tool to use for the implementation of the AKD algorithm. Table 4.4 and 
Fig 4.7 show the percentage of RMI overhead in key generation as well as share server 
operations (signature share generation). Table 4.5 gives the relative amount of time taken 
by the Share Servers and the Special Server for signing their shares.