linux-imx

/* RSA asymmetric public-key algorithm [RFC3447]

 *

 * Copyright (c) 2015, Intel Corporation

 * Authors: Tadeusz Struk <tadeusz.struk@intel.com>

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public Licence

 * as published by the Free Software Foundation; either version

 * 2 of the Licence, or (at your option) any later version.

 */

​

#include <linux/module.h>

#include <linux/mpi.h>

#include <crypto/internal/rsa.h>

#include <crypto/internal/akcipher.h>

#include <crypto/akcipher.h>

#include <crypto/algapi.h>

​

struct rsa_mpi_key {

    MPI n;

    MPI e;

    MPI d;

};

​

/*

 * RSAEP function [RFC3447 sec 5.1.1]

 * c = m^e mod n;

 */

static int _rsa_enc(const struct rsa_mpi_key *key, MPI c, MPI m)

{

    /* (1) Validate 0 <= m < n */

    if (mpi_cmp_ui(m, 0) < 0 || mpi_cmp(m, key->n) >= 0)

        return -EINVAL;

​

    /* (2) c = m^e mod n */

    return mpi_powm(c, m, key->e, key->n);

}

​

/*

 * RSADP function [RFC3447 sec 5.1.2]

 * m = c^d mod n;

 */

static int _rsa_dec(const struct rsa_mpi_key *key, MPI m, MPI c)

{

    /* (1) Validate 0 <= c < n */

    if (mpi_cmp_ui(c, 0) < 0 || mpi_cmp(c, key->n) >= 0)

        return -EINVAL;

​

    /* (2) m = c^d mod n */

    return mpi_powm(m, c, key->d, key->n);

}

​

/*

 * RSASP1 function [RFC3447 sec 5.2.1]

 * s = m^d mod n

 */

static int _rsa_sign(const struct rsa_mpi_key *key, MPI s, MPI m)

{

    /* (1) Validate 0 <= m < n */

    if (mpi_cmp_ui(m, 0) < 0 || mpi_cmp(m, key->n) >= 0)

        return -EINVAL;

​

    /* (2) s = m^d mod n */