Using the BouncyCastle library (although I guess the library is sort of irrelevant) I often run into algorithm IDs specified as ASN.1 identifiers. For example, the signature algorithm for a certificate might be "1.2.840.113549.1.1.11".
Is there a proper way to convert this into some kind of human-readable form that doesn't involve finding every ID I can get my hands on and manually building a gigantic lookup table?
Specifically for signature algorithms, you can use the class org.bouncycastle.operator.DefaultAlgorithmNameFinder. But - if I'm not wrong - this was introduced only in newer versions (I'm using Bouncy Castle 1.57 - I also checked in 1.46 and it doesn't have this class).
The use is straighforward:
DefaultAlgorithmNameFinder algFinder = new DefaultAlgorithmNameFinder();
System.out.println(algFinder.getAlgorithmName(new ASN1ObjectIdentifier("1.2.840.113549.1.1.11")));
The output is:
SHA256WITHRSA
According to javadoc, if it can't find a human-friendly name, it returns the same OID used in the input.
Also note that (as stated in @pepo's answer) the human-friendly names might not be the same among different tools. While BouncyCastle returns SHA256WITHRSA, the OID repository website uses sha256WithRSAEncryption.
For other OIDs (such as extensions and other fields), I couldn't find anything in the API, so the only alternative seems to be the big lookup table.
Yes. It is this one: org.bouncycastle.asn1.pkcs.PKCSObjectIdentifiers.sha256WithRSAEncryption.
For extensions, see org.bouncycastle.asn1.x509.Extension list of ASN1ObjectIdentifier.
