Throw BadPaddingException on RSA decrypt failures

[cconlon]

This PR fixes RSA decrypt exception handling in WolfCryptCipher to match expected JCE Cipher behavior:

• Throw javax.crypto.BadPaddingException on RSA/ECB/PKCS1Padding and RSA/ECB/OAEP* decrypt failures, instead of propagating a WolfCryptException.
• Throw IllegalBlockSizeException when RSA decrypt input length does not match the modulus size.

Includes JUnit tests to prevent regression.

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

This PR aligns WolfCryptCipher RSA decrypt error handling with JCE Cipher expectations by mapping native RSA decrypt failures to JCE exceptions and adding regression tests for wrong-key decrypt paths.

Changes:

• Map RSA OAEP and PKCS#1 decrypt failures to BadPaddingException instead of propagating WolfCryptException.
• Add RSA decrypt input-length checks intended to throw IllegalBlockSizeException when ciphertext length doesn’t match the modulus size.
• Add JUnit regression tests covering wrong-key decrypt scenarios and tighten existing “too big data” expectations.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 5 comments.

File	Description
src/main/java/com/wolfssl/provider/jce/WolfCryptCipher.java	Adds RSA ciphertext length checks and remaps native decrypt errors to BadPaddingException.
src/test/java/com/wolfssl/provider/jce/test/WolfCryptCipherTest.java	Adds regression tests and test vectors for wrong-key RSA decrypt; updates expectations for oversize input.

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[wolfSSL-Fenrir-bot]

Fenrir Automated Review — PR #216

Scan targets checked: wolfcrypt-jni-bugs, wolfcrypt-jni-src

No new issues found in the changed files. ✅