Sending secret value in identity-based encryption
Using xor : $K \oplus e(g,h)^{\gamma}$
Using symmetric key: Assuming $Key=e(g,h)^{\gamma}$ and encrypt $K$ using $Key$.
Which one is better in performance?

  • $\begingroup$ Just to be sure: Do you mean "performance" as in "speed", or are you hinting at something else (like "security")? $\endgroup$ – e-sushi Jun 9 '16 at 14:48
  • $\begingroup$ Good question, I assumed speed in the answer below. $\endgroup$ – Maarten Bodewes Jun 9 '16 at 17:01
  • $\begingroup$ e-sushi. speed. $\endgroup$ – myat Jun 23 '16 at 5:36

If you assume that you can use a one-time-pad they would be equivalent. Otherwise a cipher will always be slower than XOR.

The chances that it matters much compared to the other functions required is about zero though.

| improve this answer | |
  • $\begingroup$ Note: I'm not an expert in identity based encryption (yet), but this question seems to be answerable without expert knowledge. I'm not sure if an IV is required for above function though. $\endgroup$ – Maarten Bodewes Jun 9 '16 at 11:21

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