I'm currently looking at changing the padding type from one of the Oracle Padding attacks to a secure one. Would this break data already encrypted using the old method?

  • $\begingroup$ Mainly out of curiosity, which padding mode would you be changing from and to which mode? $\endgroup$
    – otus
    Commented Mar 23, 2016 at 7:53
  • $\begingroup$ Presumably PKCS#1v1.5 to OAEP. $\endgroup$ Commented Mar 23, 2016 at 7:53
  • $\begingroup$ To make matters worse, if you still support the old vulnerable algorithm, you'd probably still be vulnerable to padding oracles, even for data that was encrypted using the new algorithm as long as you use the same RSA key for both. $\endgroup$ Commented Mar 23, 2016 at 7:54
  • $\begingroup$ @CodesInChaos you would be correct. And thanks for the awesome answer you had. $\endgroup$
    – Matt
    Commented Mar 28, 2016 at 0:01

1 Answer 1


Yes, every RSA padding I'm familiar with is incompatible with the other schemes.


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