What does "e is 65537 (0x10001)" mean?

openssl primes
jsbeckr picture jsbeckr · May 24, 2012 · Viewed 24.6k times · Source

I want to know what the output e is 65537 (0x10001) means. It happens during the RSA Key Generation using openssl genrsa. I know that the dots mean that the number has passed a probe division and the plus is printed out after it passed a miller rabin test. But i can't figure out what the last info message before the RSA key is printed out means.

I can't find it in the openssl docs. And I could use it in term paper on prime number generation. Thanks for your help! :)

Answer

Raymond Tau picture Raymond Tau · May 24, 2012

The "e" is the public exponent, in openssl genrsa, you can use the option -F4 or -3 to choose between 65537 and 3.

For information on public exponent, you may take a look on this question: https://security.stackexchange.com/questions/2335/should-rsa-public-exponent-be-only-in-3-5-17-257-or-65537-due-to-security-c

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