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330234638e
This patch adds a default null skcipher for users such as gcm to perform copies on SG lists. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
222 lines
5.3 KiB
C
222 lines
5.3 KiB
C
/*
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* Cryptographic API.
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*
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* Null algorithms, aka Much Ado About Nothing.
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*
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* These are needed for IPsec, and may be useful in general for
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* testing & debugging.
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*
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* The null cipher is compliant with RFC2410.
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*
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* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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*/
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#include <crypto/null.h>
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#include <crypto/internal/hash.h>
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#include <crypto/internal/skcipher.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <linux/string.h>
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static DEFINE_MUTEX(crypto_default_null_skcipher_lock);
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static struct crypto_blkcipher *crypto_default_null_skcipher;
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static int crypto_default_null_skcipher_refcnt;
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static int null_compress(struct crypto_tfm *tfm, const u8 *src,
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unsigned int slen, u8 *dst, unsigned int *dlen)
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{
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if (slen > *dlen)
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return -EINVAL;
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memcpy(dst, src, slen);
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*dlen = slen;
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return 0;
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}
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static int null_init(struct shash_desc *desc)
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{
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return 0;
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}
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static int null_update(struct shash_desc *desc, const u8 *data,
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unsigned int len)
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{
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return 0;
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}
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static int null_final(struct shash_desc *desc, u8 *out)
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{
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return 0;
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}
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static int null_digest(struct shash_desc *desc, const u8 *data,
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unsigned int len, u8 *out)
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{
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return 0;
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}
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static int null_hash_setkey(struct crypto_shash *tfm, const u8 *key,
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unsigned int keylen)
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{ return 0; }
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static int null_setkey(struct crypto_tfm *tfm, const u8 *key,
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unsigned int keylen)
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{ return 0; }
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static void null_crypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
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{
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memcpy(dst, src, NULL_BLOCK_SIZE);
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}
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static int skcipher_null_crypt(struct blkcipher_desc *desc,
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struct scatterlist *dst,
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struct scatterlist *src, unsigned int nbytes)
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{
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struct blkcipher_walk walk;
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int err;
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blkcipher_walk_init(&walk, dst, src, nbytes);
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err = blkcipher_walk_virt(desc, &walk);
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while (walk.nbytes) {
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if (walk.src.virt.addr != walk.dst.virt.addr)
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memcpy(walk.dst.virt.addr, walk.src.virt.addr,
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walk.nbytes);
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err = blkcipher_walk_done(desc, &walk, 0);
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}
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return err;
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}
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static struct shash_alg digest_null = {
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.digestsize = NULL_DIGEST_SIZE,
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.setkey = null_hash_setkey,
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.init = null_init,
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.update = null_update,
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.finup = null_digest,
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.digest = null_digest,
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.final = null_final,
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.base = {
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.cra_name = "digest_null",
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.cra_flags = CRYPTO_ALG_TYPE_SHASH,
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.cra_blocksize = NULL_BLOCK_SIZE,
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.cra_module = THIS_MODULE,
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}
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};
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static struct crypto_alg null_algs[3] = { {
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.cra_name = "cipher_null",
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.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
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.cra_blocksize = NULL_BLOCK_SIZE,
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.cra_ctxsize = 0,
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.cra_module = THIS_MODULE,
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.cra_u = { .cipher = {
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.cia_min_keysize = NULL_KEY_SIZE,
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.cia_max_keysize = NULL_KEY_SIZE,
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.cia_setkey = null_setkey,
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.cia_encrypt = null_crypt,
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.cia_decrypt = null_crypt } }
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}, {
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.cra_name = "ecb(cipher_null)",
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.cra_driver_name = "ecb-cipher_null",
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.cra_priority = 100,
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.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER,
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.cra_blocksize = NULL_BLOCK_SIZE,
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.cra_type = &crypto_blkcipher_type,
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.cra_ctxsize = 0,
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.cra_module = THIS_MODULE,
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.cra_u = { .blkcipher = {
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.min_keysize = NULL_KEY_SIZE,
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.max_keysize = NULL_KEY_SIZE,
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.ivsize = NULL_IV_SIZE,
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.setkey = null_setkey,
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.encrypt = skcipher_null_crypt,
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.decrypt = skcipher_null_crypt } }
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}, {
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.cra_name = "compress_null",
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.cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
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.cra_blocksize = NULL_BLOCK_SIZE,
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.cra_ctxsize = 0,
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.cra_module = THIS_MODULE,
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.cra_u = { .compress = {
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.coa_compress = null_compress,
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.coa_decompress = null_compress } }
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} };
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MODULE_ALIAS_CRYPTO("compress_null");
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MODULE_ALIAS_CRYPTO("digest_null");
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MODULE_ALIAS_CRYPTO("cipher_null");
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struct crypto_blkcipher *crypto_get_default_null_skcipher(void)
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{
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struct crypto_blkcipher *tfm;
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mutex_lock(&crypto_default_null_skcipher_lock);
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tfm = crypto_default_null_skcipher;
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if (!tfm) {
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tfm = crypto_alloc_blkcipher("ecb(cipher_null)", 0, 0);
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if (IS_ERR(tfm))
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goto unlock;
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crypto_default_null_skcipher = tfm;
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}
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crypto_default_null_skcipher_refcnt++;
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unlock:
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mutex_unlock(&crypto_default_null_skcipher_lock);
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return tfm;
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}
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EXPORT_SYMBOL_GPL(crypto_get_default_null_skcipher);
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void crypto_put_default_null_skcipher(void)
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{
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mutex_lock(&crypto_default_null_skcipher_lock);
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if (!--crypto_default_null_skcipher_refcnt) {
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crypto_free_blkcipher(crypto_default_null_skcipher);
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crypto_default_null_skcipher = NULL;
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}
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mutex_unlock(&crypto_default_null_skcipher_lock);
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}
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EXPORT_SYMBOL_GPL(crypto_put_default_null_skcipher);
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static int __init crypto_null_mod_init(void)
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{
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int ret = 0;
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ret = crypto_register_algs(null_algs, ARRAY_SIZE(null_algs));
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if (ret < 0)
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goto out;
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ret = crypto_register_shash(&digest_null);
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if (ret < 0)
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goto out_unregister_algs;
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return 0;
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out_unregister_algs:
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crypto_unregister_algs(null_algs, ARRAY_SIZE(null_algs));
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out:
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return ret;
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}
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static void __exit crypto_null_mod_fini(void)
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{
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crypto_unregister_shash(&digest_null);
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crypto_unregister_algs(null_algs, ARRAY_SIZE(null_algs));
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}
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module_init(crypto_null_mod_init);
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module_exit(crypto_null_mod_fini);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Null Cryptographic Algorithms");
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