Fix RC2-40-CBC Errors When Opening a PFX in OpenSSL 3

If openssl pkcs12 fails with an error containing unsupported and Algorithm (RC2-40-CBC : 0), check the encryption used by the PFX archive. OpenSSL 3 supplies RC2 through its legacy provider.

Inspect the old PFX without exporting credentials

For an archive you’re authorized to inspect, load the legacy provider for this command:

openssl pkcs12 -legacy -in old.pfx -info -noout

Enter the archive password at the prompt. -info reports the archive structure and encryption algorithms. -noout suppresses certificate and key output.

If you see Mac verify error: invalid password?, check the password and try a fresh export from the source system. Keep integrity verification enabled.

Re-export with modern encryption

If the consuming application supports modern PKCS#12 encryption, re-export the identity into a fresh archive using OpenSSL 3 defaults. For a bundle with one identity, extract the leaf certificate, any intermediates you need to retain, and an encrypted PEM copy of the private key. Work in a private directory and keep the original archive for rollback.

After re-exporting, check that the new archive opens with the default provider:

openssl pkcs12 -in modern.p12 -info -noout

Compare the leaf’s SHA-256 fingerprint with the original, confirm the expected intermediates are present, and test the new archive in the application that will use it. Repacking changes the archive encryption. The certificates and their signatures stay the same.

The full PKIScope walkthrough includes the extraction, re-export, and fingerprint comparison commands.

AI was used to draft this post. The RC2 failure and re-export workflow were tested with OpenSSL 3.5.7.