Calling EVP_DigestFinal_ex multiple times

Matt Caswell matt at
Mon Jun 17 09:06:48 UTC 2019

On 15/06/2019 15:08, Tobias Nießen wrote:
> Hello,
> I am wondering whether it is permitted to call EVP_DigestFinal_ex multiple
> times on the same context in order to retrieve the same digest twice. I
> expected OpenSSL to fail with an error code, but SHA256 seems to permit it
> whereas SHA3 seems to cause a segmentation fault. The documentation does not
> explicitely forbid or allow it, so I am wondering where this should be
> addressed: In the implementation of EVP_*, in SHA2, in SHA3, in the
> documentation, or not at all?

I believe this should not be allowed. Probably this is a documentation issue.


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