question: RSAPrivateKeyImpl ( BigInteger n , BigInteger d ) throws InvalidKeyException { this . n = n ; this . d = d ; RSAKeyFactory . checkRSAProviderKeyLengths ( n . bitLength ( ) , null ) ; algid = RSAPrivateCrtKeyImpl . rsaId ; try { DerOutputStream out = new DerOutputStream ( ) ; out . putInteger ( 0 ) ; out . putInteger ( n ) ; out . putInteger ( 0 ) ; out . putInteger ( d ) ; out . putInteger ( 0 ) ; out . putInteger ( 0 ) ; out . putInteger ( 0 ) ; out . putInteger ( 0 ) ; out . putInteger ( 0 ) ; DerValue val = new DerValue ( DerValue . tag_Sequence , out . toByteArray ( ) ) ; key = val . toByteArray ( ) ; } catch ( IOException exc ) { throw new InvalidKeyException ( exc ) ; } }
target:  Construct a key from its components. Used by the RSAKeyFactory and the RSAKeyPairGenerator.