static int x509parse_key_pkcs1_der( rsa_context *rsa,
                                    const unsigned char *key,
                                    size_t keylen )
{
    int ret;
    size_t len;
    unsigned char *p, *end;

    p = (unsigned char *) key;
    end = p + keylen;

    /*
     * This function parses the RSAPrivateKey (PKCS#1)
     *
     *  RSAPrivateKey ::= SEQUENCE {
     *      version           Version,
     *      modulus           INTEGER,  -- n
     *      publicExponent    INTEGER,  -- e
     *      privateExponent   INTEGER,  -- d
     *      prime1            INTEGER,  -- p
     *      prime2            INTEGER,  -- q
     *      exponent1         INTEGER,  -- d mod (p-1)
     *      exponent2         INTEGER,  -- d mod (q-1)
     *      coefficient       INTEGER,  -- (inverse of q) mod p
     *      otherPrimeInfos   OtherPrimeInfos OPTIONAL
     *  }
     */
    if( ( ret = asn1_get_tag( &p, end, &len,
            ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 )
    {
        return( POLARSSL_ERR_X509_KEY_INVALID_FORMAT + ret );
    }

    end = p + len;

    if( ( ret = asn1_get_int( &p, end, &rsa->ver ) ) != 0 )
    {
        return( POLARSSL_ERR_X509_KEY_INVALID_FORMAT + ret );
    }

    if( rsa->ver != 0 )
    {
        return( POLARSSL_ERR_X509_KEY_INVALID_VERSION + ret );
    }

    if( ( ret = asn1_get_mpi( &p, end, &rsa->N  ) ) != 0 ||
        ( ret = asn1_get_mpi( &p, end, &rsa->E  ) ) != 0 ||
        ( ret = asn1_get_mpi( &p, end, &rsa->D  ) ) != 0 ||
        ( ret = asn1_get_mpi( &p, end, &rsa->P  ) ) != 0 ||
        ( ret = asn1_get_mpi( &p, end, &rsa->Q  ) ) != 0 ||
        ( ret = asn1_get_mpi( &p, end, &rsa->DP ) ) != 0 ||
        ( ret = asn1_get_mpi( &p, end, &rsa->DQ ) ) != 0 ||
        ( ret = asn1_get_mpi( &p, end, &rsa->QP ) ) != 0 )
    {
        rsa_free( rsa );
        return( POLARSSL_ERR_X509_KEY_INVALID_FORMAT + ret );
    }

    rsa->len = mpi_size( &rsa->N );

    if( p != end )
    {
        rsa_free( rsa );
        return( POLARSSL_ERR_X509_KEY_INVALID_FORMAT +
                POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
    }

    if( ( ret = rsa_check_privkey( rsa ) ) != 0 )
    {
        rsa_free( rsa );
        return( ret );
    }

    return( 0 );
}
static int x509parse_key_pkcs1_der( rsa_context *rsa,
                                    const unsigned char *key,
                                    size_t keylen )
{
    int ret;
    size_t len;
    unsigned char *p, *end;

    p = (unsigned char *) key;
    end = p + keylen;

     
    if( ( ret = asn1_get_tag( &p, end, &len,
            ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 )
    {
        return( POLARSSL_ERR_X509_KEY_INVALID_FORMAT + ret );
    }

    end = p + len;

    if( ( ret = asn1_get_int( &p, end, &rsa->ver ) ) != 0 )
    {
        return( POLARSSL_ERR_X509_KEY_INVALID_FORMAT + ret );
    }

    if( rsa->ver != 0 )
    {
        return( POLARSSL_ERR_X509_KEY_INVALID_VERSION + ret );
    }

    if( ( ret = asn1_get_mpi( &p, end, &rsa->N  ) ) != 0 ||
        ( ret = asn1_get_mpi( &p, end, &rsa->E  ) ) != 0 ||
        ( ret = asn1_get_mpi( &p, end, &rsa->D  ) ) != 0 ||
        ( ret = asn1_get_mpi( &p, end, &rsa->P  ) ) != 0 ||
        ( ret = asn1_get_mpi( &p, end, &rsa->Q  ) ) != 0 ||
        ( ret = asn1_get_mpi( &p, end, &rsa->DP ) ) != 0 ||
        ( ret = asn1_get_mpi( &p, end, &rsa->DQ ) ) != 0 ||
        ( ret = asn1_get_mpi( &p, end, &rsa->QP ) ) != 0 )
    {
        rsa_free( rsa );
        return( POLARSSL_ERR_X509_KEY_INVALID_FORMAT + ret );
    }

    rsa->len = mpi_size( &rsa->N );

    if( p != end )
    {
        rsa_free( rsa );
        return( POLARSSL_ERR_X509_KEY_INVALID_FORMAT +
                POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
    }

    if( ( ret = rsa_check_privkey( rsa ) ) != 0 )
    {
        rsa_free( rsa );
        return( ret );
    }

    return( 0 );
}