Error when importing PEM private key

[ptitdoc]

When importing a traditional RSA PEM key, the following error is displayed:
Error (class org.bouncycastle.asn1.pkcs.PrivateKeyInfo cannot be cast to class org.bouncycastle.openssl.PEMKeyPair (org.bouncycastle.asn1.pkcs.PrivateKeyInfo and org.bouncycastle.openssl.PEMKeyPair are in unnamed module of loader burp.eb2 @361a5085))

[ptitdoc]

This occurs when a key is in the format :

-----BEGIN PRIVATE KEY-----
..
-----END PRIVATE KEY-----

I converted it using openssl rsa -in mykey.key -text and retrieved from -----BEGIN RSA PRIVATE KEY----- to -----END RSA PRIVATE KEY-----

[emanuelduss]

Hi

As you figured out, only traditional RSA keys are accepted.

For the other readers:

Traditional RSA key format:

------ BEGIN RSA PRIVATE KEY-----
[...]
-----END RSA PRIVATE KEY-----

PKCS8 Format:

------ BEGIN PRIVATE KEY-----
[...]
-----END PRIVATE KEY-----

Grz and have fun ;-),
Emanuel

[A1vinSmith]

openssl rsa -in server.key -out server_new.key -traditional

• https://stackoverflow.com/questions/17733536/how-to-convert-a-private-key-to-an-rsa-private-key
• https://stackoverflow.com/questions/75667753/how-do-i-get-openssl-3-to-generate-the-right-kind-of-rsa-pem-file