Android RSA SHA256 解碼

 implementation 'ch.dissem.jabit:jabit-cryptography-bouncy:1.0.1'

     public  void verifySignature() throws Exception {             PemReader reader=publicKeyReader();             InputStream data = data();       //  InputStream signatureData = signature();              final PemObject publicKeyPem = reader.readPemObject();             final byte[] publicKeyBytes = publicKeyPem.getContent();             final KeyFactory keyFactory = KeyFactory.getInstance("RSA");             final X509EncodedKeySpec publicKeySpec = new X509EncodedKeySpec(publicKeyBytes);             final RSAPublicKey publicKey = (RSAPublicKey) keyFactory.generatePublic(publicKeySpec);              final Signature signature = Signature.getInstance("SHA256withRSA");             signature.initVerify(publicKey);              final byte[] buffy = new byte[16 * 1024];             int read = -1;             while ((read = data.read(buffy)) != -1) {                 signature.update(buffy, 0, read);             }               byte[] signatureBytes = new byte[publicKey.getModulus().bitLength() / 8];          //   signatureData.read(signatureBytes);           String tmp="mafxI8/zMvfMvQQxOvOPJz6xF 6DroYv4LzQ arc gBlqS09m5TfxHx9GnIDRgjrxBef4aQ4HIf7wvWJCrkwWmaHaSI7F6xAwN5kaTXfjygiYYEH8lLlHuLQaoouBZLWxYAzP3vnmNPVzfBNrXh6a5CTqBFbX43/9rX5cpmvx6lY4nbSCvIle2vYNgCi7HJtRqfBPxGjRZXdIdJk0lDjCSZfgfBQHLBEed8XxkUQFCkFlHN5Jx7Pp13aiJ3kY1lmoFmxVb95HDbcLZdSQDUit3T94gc7OsazdBDrvmLlxGzxUeuU7aaxa0dSCUH1yGr1DceKU5lywr1aiRsaZYxjg9ynRPzBXpf3l6TReilANFvfCGR6tpy4H77Ma/y4cSN2rO7J0Cd12v/D MV2ITFAM30kZmGbSOe91Fo77ynveZPdwWQzDrjaUHL/sZ5ijDQkz  fNioLohPj7 caQVFE2moEekAUJp uDzOcJHgi4VivOJ4Riv/seutZ4eIS7vx3jUqRrAzRA6E5SSleIc9GitgC eePvcFSuI0WLpuxtHo6T6s7kOhzloXWiImP2ED1J TMgRPtY4snGtlHcILSXuxlFL8PF5mi W/gOsSMdVtOFKLNLSrb/TPK0Fze1zO1ZGkY iiplMn OkGyao3OfbEhuA3vsCVAmASKV3qk5F4=";           InputStream in=new ByteArrayInputStream(Base64.decode(tmp.getBytes(),Base64.NO_WRAP));         byte[] signatureBytes2 = new byte[publicKey.getModulus().bitLength() / 8];         in.read(signatureBytes2);           Log.i("b","1  " signature.verify(signatureBytes2));        //  Log.i("b","2  " signature.verify(signatureBytes));      }       private  InputStream data() throws FileNotFoundException {         return new FileInputStream("/storage/emulated/0/Download/test.zip");     }      private  PemReader publicKeyReader() throws FileNotFoundException {         //return new PemReader(new InputStreamReader(new FileInputStream("/storage/emulated/0/Download/publickey.pem")));         try {             return new PemReader(new InputStreamReader(getResources().openRawResource(R.raw.publickey)));         } catch (Exception e) {             e.printStackTrace();         }         return null;     }      private  InputStream signature() throws FileNotFoundException {         return new FileInputStream("/storage/emulated/0/test.zip.dgst.signed");     }

data()是您下载的源文件

publickKeyReader()是你的public key文件

signature() 就是你的signature文件

tmp我从服务器上得到它，然后用它base64解码，得到和谐signature文件的内容相同，所以这个signature文件可以直接从服务器上使用或替换。