OpenSSL 3.0 needs the legacy provider.

[sambitdash]

OpenSSL 3.0 has put the weak ciphers in the legacy provider which is not built by default.

Old PDF files used RC4 which is unavailable with the OpenSSL 3.0 default provider. PDFIO.jl needs the legacy provider to open the old PDF password-protected files.

[sambitdash]

This site gives some ideas for building the legacy provider.

https://help.heroku.com/88GYDTB2/how-do-i-configure-openssl-to-allow-the-use-of-legacy-cryptographic-algorithms

[eschnett]

Looking at this page I think that the issue is that the legacy provider is not "loaded", which appears to happen at run time. The instructions given on that page seem to be about configuring OpenSSL (at run time) to enable the legacy provider. I do not see instructions that would apply to building OpenSSL.

Also, there is a strong warning against enabling the legacy provider by default because this would make things less secure by default.

[sambitdash]

@eschnett, thanks a lot for looking into this issue. PDF documents are of archival value. Although RC4 is bad encryption for TLS/SSL connections, you have old password-protected PDF files that cannot be read unless we have RC4 data decrypted.

You are right about the page I shared. Please ignore it. I do not use the OpenSSL application but use the libcrypto.dll. But, when I try to load the legacy provider, I get an error. I wonder if the legacy provider DLL is even built as part of the OpenSSL binaries.

Can you share the binary locations for OpenSSL 3.0 for me to investigate?

[eschnett]

If you use the OpenSSL_jll module from Julia, then you can use tab completion in the repl to see what functions this module exports. One of the functions points to the library file that has been loaded.

Otherwise, go to https://github.com/JuliaBinaryWrappers/OpenSSL_jll.jl and look into the Artifacts.toml file there. Examine this file manually until you find your operating system and architecture (probably os = windows, arch = x86_64, and nearby will be a url pointing to the tarball that Julia would download. This tarball will contain the dynamic library and other accompanying files.

[sambitdash]

We do not need the Legacy provider as I have implemented RC4. So, closing it for now.