How to add an alias to java.security.Provider?

Question

I need to verify digital signature in a pdf file.
I use itextpdf and cryptopro

cryptopro provides these aliases for the needed algorithm:

, JCP: Signature.GOST3411withGOST3410EL -> ru.CryptoPro.JCP.Sign.GostElSign
  aliases: [1.2.643.2.2.3, OID.1.2.643.2.2.3, 1.2.643.2.2.9with1.2.643.2.2.19]

itextpdf tries to get "GOST3411withECGOST3410" and fails with: "no such algorithm: GOST3411withECGOST3410 for provider JCP"

This works:

Provider prov = Security.getProvider(PROVIDER_NAME);
prov.put("Alg.Alias.Signature.GOST3411withECGOST3410", "GOST3411withGOST3410EL");

Not sure it's a correct way though.

Exception in thread "main" ExceptionConverter: java.security.NoSuchAlgorithmException: no such algorithm: GOST3411withECGOST3410 for provider JCP
    at sun.security.jca.GetInstance.getService(GetInstance.java:70)
    at sun.security.jca.GetInstance.getInstance(GetInstance.java:190)
    at java.security.Signature.getInstance(Signature.java:324)
    at com.itextpdf.text.pdf.security.PdfPKCS7.initSignature(PdfPKCS7.java:692)
    at com.itextpdf.text.pdf.security.PdfPKCS7.<init>(PdfPKCS7.java:452)
    at com.itextpdf.text.pdf.AcroFields.verifySignature(AcroFields.java:2349)
    at org.foo.PdfVerifier.verify(PdfVerifier.java:83)
    at org.foo.PdfVerifier.main(PdfVerifier.java:53)

Answer 1

What you do is Ok and practically you have no other choice.

However, the true problem lies in the way itextpdf works. It hardcodes BouncyCastle's names for key algorithms ECGOST3410, while CryptoPro JCP has the GOST3410EL name for the same algorithm. This makes it difficult to switch to use keys produced by different security provider like in your case.

The library can get the same values from keys using Key.getAlgorithm(), which will eliminate the need for hardcoding and make the library less "security provider dependent." Hardcoding is an especially bad idea taking into account that PdfPKCS7 constructor allows security provider selection.