Calling EVP_DigestFinal_ex multiple times

[Tobias Nießen]

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?

Thank you in advance!
Tobias