// SPDX-License-Identifier: GPL-2.0
/*
* Adiantum length-preserving encryption mode
*
* Copyright 2018 Google LLC
*/
/*
* Adiantum is a tweakable, length-preserving encryption mode designed for fast
* and secure disk encryption, especially on CPUs without dedicated crypto
* instructions. Adiantum encrypts each sector using the XChaCha12 stream
* cipher, two passes of an ε-almost-∆-universal (ε-∆U) hash function based on
* NH and Poly1305, and an invocation of the AES-256 block cipher on a single
* 16-byte block. See the paper for details:
*
* Adiantum: length-preserving encryption for entry-level processors
* (https://eprint.iacr.org/2018/720.pdf)
*
* For flexibility, this implementation also allows other ciphers:
*
* - Stream cipher: XChaCha12 or XChaCha20
* - Block cipher: any with a 128-bit block size and 256-bit key
*
* This implementation doesn't currently allow other ε-∆U hash functions, i.e.
* HPolyC is not supported. This is because Adiantum is ~20% faster than HPolyC
* but still provably as secure, and also the ε-∆U hash function of HBSH is
* formally defined to take two inputs (tweak, message) which makes it difficult
* to wrap with the crypto_shash API. Rather, some details need to be handled
* here. Nevertheless, if needed in the future, support for other ε-∆U hash
* functions could be added here.
*/
#include <crypto/b128ops.h>
#include <crypto/chacha.h>
#include <crypto/internal/cipher.h>
#include <crypto/internal/hash.h>
#include <crypto/internal/poly1305.h>
#include <crypto/internal/skcipher.h>
#include <crypto/nhpoly1305.h>
#include <crypto/scatterwalk.h>
#include <linux/module.h>
/*
* Size of right-hand part of input data, in bytes; also the size of the block
* cipher's block size and the hash function's output.
*/
#define BLOCKCIPHER_BLOCK_SIZE 16
/* Size of the block cipher key (K_E) in bytes */
#define BLOCKCIPHER_KEY_SIZE 32
/* Size of the hash key (K_H) in bytes */
#define HASH_KEY_SIZE (POLY1305_BLOCK_SIZE + NHPOLY1305_KEY_SIZE)
/*
* The specification allows variable-length tweaks, but Linux's crypto API
* currently only allows algorithms to support a single length. The "natural"
* tweak length for Adiantum is 16, since that fits into one Poly1305 block for
* the best performance. But longer tweaks are useful for fscrypt, to avoid
* needing to derive per-file keys. So instead we use two blocks, or 32 bytes.
*/
#define TWEAK_SIZE 32
struct adiantum_instance_ctx {
struct crypto_skcipher_spawn streamcipher_spawn;
struct crypto_cipher_spawn blockcipher_spawn;
struct crypto_shash_spawn hash_spawn;
};
struct adiantum_tfm_ctx {
struct crypto_skcipher *streamcipher;
struct crypto_cipher *blockcipher;
struct crypto_shash *hash;
struct poly1305_core_key header_hash_key;
};
struct adiantum_request_ctx {
/*
* Buffer for right-hand part of data, i.e.
*
* P_L => P_M => C_M => C_R when encrypting, or
* C_R => C_M => P_M => P_L when decrypting.
*
* Also used to build the IV for the stream cipher.
*/
union {
u8 bytes[XCHACHA_IV_SIZE];
__le32 words[XCHACHA_IV_SIZE / sizeof(__le32)];
le128 bignum; /* interpret as element of Z/(2^{128}Z) */
} rbuf;
bool enc; /* true if encrypting, false if decrypting */
/*
* The result of the Poly1305 ε-∆U hash function applied to
* (bulk length, tweak)
*/
le128 header_hash;
/* Sub-requests, must be last */
union {
struct shash_desc hash_desc;
struct skcipher_request streamcipher_req;
} u;
};
/*
* Given the XChaCha stream key K_S, derive the block cipher key K_E and the
* hash key K_H as follows:
*
* K_E || K_H || ... = XChaCha(key=K_S, nonce=1||0^191)
*
* Note that this denotes using bits from the XChaCha keystream, which here we
* get indirectly by encrypting a buffer containing all 0's.
*/
static int adiantum_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keylen)
{
struct adiantum_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
struct {
u8 iv[XCHACHA_IV_SIZE];
u8 derived_keys[BLOCKCIPHER_KEY_SIZE + HASH_KEY_SIZE];
struct scatterlist sg;
struct crypto_wait wait;
struct skcipher_request req; /* must be last */
} *data;
u8 *keyp;
int err;
/* Set the stream cipher key (K_S) */
crypto_skcipher_clear_flags(tctx->streamcipher, CRYPTO_TFM_REQ_MASK);
crypto_skcipher_set_flags(tctx->streamcipher,
crypto_skcipher_get_flags(tfm) &
CRYPTO_TFM_REQ_MASK);
err = crypto_skcipher_setkey(tctx->streamcipher, key, keylen);
if (err)
return err;
/* Derive the subkeys */
data = kzalloc(sizeof(*data) +
crypto_skcipher_reqsize(tctx->streamcipher), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->iv[0] = 1;
sg_init_one(&data->sg, data->derived_keys, sizeof(data->derived_keys));
crypto_init_wait(&data->wait);
skcipher_request_set_tfm(&data->req, tctx->streamcipher);
skcipher_request_set_callback(&data->req, CRYPTO_TFM_REQ_MAY_SLEEP |
CRYPTO_TFM_REQ_MAY_BACKLOG,
crypto_req_done, &data->wait);
skcipher_request_set_crypt(&data->req, &data->sg, &data->sg,
sizeof(data->derived_keys), data->iv);
err = crypto_wait_req(crypto_skcipher_encrypt(&data->req), &data->wait);
if (err)
goto out;
keyp = data->derived_keys;
/* Set the block cipher key (K_E) */
crypto_cipher_clear_flags(tctx->blockcipher, CRYPTO_TFM_REQ_MASK);
crypto_cipher_set_flags(tctx->blockcipher,
crypto_skcipher_get_flags(tfm) &
CRYPTO_TFM_REQ_MASK);
err = crypto_cipher_setkey(tctx->blockcipher, keyp,
BLOCKCIPHER_KEY_SIZE);
if (err)
goto out;
keyp += BLOCKCIPHER_KEY_SIZE;
/* Set the hash key (K_H) */
poly1305_core_setkey(&tctx->header_hash_key, keyp);
keyp += POLY1305_BLOCK_SIZE;
crypto_shash_clear_flags(tctx->hash, CRYPTO_TFM_REQ_MASK);
crypto_shash_set_flags(tctx->hash, crypto_skcipher_get_flags(tfm) &
CRYPTO_TFM_REQ_MASK);
err = crypto_shash_setkey(tctx->hash, keyp, NHPOLY1305_KEY_SIZE);
keyp += NHPOLY1305_KEY_SIZE;
WARN_ON(keyp != &data->derived_keys[ARRAY_SIZE(data->derived_keys)]);
out:
kfree_sensitive(data);
return err;
}
/* Addition in Z/(2^{128}Z) */
static inline void le128_add(le128 *r, const le128 *v1, const le128 *v2)
{
u64 x = le64_to_cpu(v1->b);
u64 y = le64_to_cpu(v2->b);
r->b = cpu_to_le64(x + y);
r->a = cpu_to_le64(le64_to_cpu(v1->a) + le64_to_cpu(v2->a) +
(x + y < x));
}
/* Subtraction in Z/(2^{128}Z) */
static inline void le128_sub(le128 *r, const le128 *v1, const le128 *v2)
{
u64 x = le64_to_cpu(v1->b);
u64 y = le64_to_cpu(v2->b);
r->b = cpu_to_le64(x - y);
r->a = cpu_to_le64(le64_to_cpu(v1->a) - le64_to_cpu(v2->a) -
(x - y > x));
}
/*
* Apply the Poly1305 ε-∆U hash function to (bulk length, tweak) and save the
* result to rctx->header_hash. This is the calculation
*
* H_T ← Poly1305_{K_T}(bin_{128}(|L|) || T)
*
* from the procedure in section 6.4 of the Adiantum paper. The resulting value
* is reused in both the first and second hash steps. Specifically, it's added
* to the result of an independently keyed ε-∆U hash function (for equal length
* inputs only) taken over the left-hand part (the "bulk") of the message, to
* give the overall Adiantum hash of the (tweak, left-hand part) pair.
*/
static void adiantum_hash_header(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
const struct adiantum_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
struct adiantum_request_ctx *rctx = skcipher_request_ctx(req);
const unsigned int bulk_len = req->cryptlen - BLOCKCIPHER_BLOCK_SIZE;
struct {
__le64 message_bits;
__le64 padding;
} header = {
.message_bits = cpu_to_le64((u64)bulk_len * 8)
};
struct poly1305_state state;
poly1305_core_init(&state);
BUILD_BUG_ON(sizeof(header) % POLY1305_BLOCK_SIZE != 0);
poly1305_core_blocks(&state, &tctx->header_hash_key,
&header, sizeof(header) / POLY1305_BLOCK_SIZE, 1);
BUILD_BUG_ON(TWEAK_SIZE % POLY1305_BLOCK_SIZE != 0);
poly1305_core_blocks(&state, &tctx->header_hash_key, req->iv,
TWEAK_SIZE / POLY1305_BLOCK_SIZE, 1);
poly1305_core_emit(&state, NULL, &rctx->header_hash);
}
/* Hash the left-hand part (the "bulk") of the message using NHPoly1305 */
static int adiantum_hash_message(struct skcipher_request *req,
struct scatterlist *sgl, unsigned int nents,
le128 *digest)
{
struct adiantum_request_ctx *rctx = skcipher_request_ctx(req);
const unsigned int bulk_len = req->cryptlen - BLOCKCIPHER_BLOCK_SIZE;
struct shash_desc *hash_desc = &rctx->u.hash_desc;
struct sg_mapping_iter miter;
unsigned int i, n;
int err;
err = crypto_shash_init(hash_desc);
if (err)
return err;
sg_miter_start(&miter, sgl, nents, SG_MITER_FROM_SG | SG_MITER_ATOMIC);
for (i = 0; i < bulk_len; i += n) {
sg_miter_next(&miter);
n = min_t(unsigned int, miter.length, bulk_len - i);
err = crypto_shash_update(hash_desc, miter.addr, n);
if (err)
break;
}
sg_miter_stop(&miter);
if (err)
return err;
return crypto_shash_final(hash_desc, (u8 *)digest);
}
/* Continue Adiantum encryption/decryption after the stream cipher step */
static int adiantum_finish(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
const struct adiantum_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
struct adiantum_request_ctx *rctx = skcipher_request_ctx(req);
const unsigned int bulk_len = req->cryptlen - BLOCKCIPHER_BLOCK_SIZE;
struct scatterlist *dst = req->dst;
const unsigned int dst_nents = sg_nents(dst);
le128 digest;
int err;
/* If decrypting, decrypt C_M with the block cipher to get P_M */
if (!rctx->enc)
crypto_cipher_decrypt_one(tctx->blockcipher, rctx->rbuf.bytes,
rctx->rbuf.bytes);
/*
* Second hash step
* enc: C_R = C_M - H_{K_H}(T, C_L)
* dec: P_R = P_M - H_{K_H}(T, P_L)
*/
rctx->u.hash_desc.tfm = tctx->hash;
le128_sub(&rctx->rbuf.bignum, &rctx->rbuf.bignum, &rctx->header_hash);
if (dst_nents == 1 && dst->offset + req->cryptlen <= PAGE_SIZE) {
/* Fast path for single-page destination */
struct page *page = sg_page(dst);
void *virt = kmap_local_page(page) + dst->offset;
err = crypto_shash_digest(&rctx->u.hash_desc, virt, bulk_len,
(u8 *)&digest);
if (err) {
kunmap_local(virt);
return err;
}
le128_sub(&rctx->rbuf.bignum, &rctx->rbuf.bignum, &digest);
memcpy(virt + bulk_len, &rctx->rbuf.bignum, sizeof(le128));
flush_dcache_page(page);
kunmap_local(virt);
} else {
/* Slow path that works for any destination scatterlist */
err = adiantum_hash_message(req, dst, dst_nents, &digest);
if (err)
return err;
le128_sub(&rctx->rbuf.bignum, &rctx->rbuf.bignum, &digest);
scatterwalk_map_and_copy(&rctx->rbuf.bignum, dst,
bulk_len, sizeof(le128), 1);
}
return 0;
}
static void adiantum_streamcipher_done(void *data, int err)
{
struct skcipher_request *req = data;
if (!err)
err = adiantum_finish(req);
skcipher_request_complete(req, err);
}
static int adiantum_crypt(struct skcipher_request *req, bool enc)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
const struct adiantum_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
struct adiantum_request_ctx *rctx = skcipher_request_ctx(req);
const unsigned int bulk_len = req->cryptlen - BLOCKCIPHER_BLOCK_SIZE;
struct scatterlist *src = req->src;
const unsigned int src_nents = sg_nents(src);
unsigned int stream_len;
le128 digest;
int err;
if (req->cryptlen < BLOCKCIPHER_BLOCK_SIZE)
return -EINVAL;
rctx->enc = enc;
/*
* First hash step
* enc: P_M = P_R + H_{K_H}(T, P_L)
* dec: C_M = C_R + H_{K_H}(T, C_L)
*/
adiantum_hash_header(req);
rctx->u.hash_desc.tfm = tctx->hash;
if (src_nents == 1 && src->offset + req->cryptlen <= PAGE_SIZE) {
/* Fast path for single-page source */
void *virt = kmap_local_page(sg_page(src)) + src->offset;
err = crypto_shash_digest(&rctx->u.hash_desc, virt, bulk_len,
(u8 *)&digest);
memcpy(&rctx->rbuf.bignum, virt + bulk_len, sizeof(le128));
kunmap_local(virt);
} else {
/* Slow path that works for any source scatterlist */
err = adiantum_hash_message(req, src, src_nents, &digest);
scatterwalk_map_and_copy(&rctx->rbuf.bignum, src,
bulk_len, sizeof(le128), 0);
}
if (err)
return err;
le128_add(&rctx->rbuf.bignum, &rctx->rbuf.bignum, &rctx->header_hash);
le128_add(&rctx->rbuf.bignum, &rctx->rbuf.bignum, &digest);
/* If encrypting, encrypt P_M with the block cipher to get C_M */
if (enc)
crypto_cipher_encrypt_one(tctx->blockcipher, rctx->rbuf.bytes,
rctx->rbuf.bytes);
/* Initialize the rest of the XChaCha IV (first part is C_M) */
BUILD_BUG_ON(BLOCKCIPHER_BLOCK_SIZE != 16);
BUILD_BUG_ON(XCHACHA_IV_SIZE != 32); /* nonce || stream position */
rctx->rbuf.words[4] = cpu_to_le32(1);
rctx->rbuf.words[5] = 0;
rctx->rbuf.words[6] = 0;
rctx->rbuf.words[7] = 0;
/*
* XChaCha needs to be done on all the data except the last 16 bytes;
* for disk encryption that usually means 4080 or 496 bytes. But ChaCha
* implementations tend to be most efficient when passed a whole number
* of 64-byte ChaCha blocks, or sometimes even a multiple of 256 bytes.
* And here it doesn't matter whether the last 16 bytes are written to,
* as the second hash step will overwrite them. Thus, round the XChaCha
* length up to the next 64-byte boundary if possible.
*/
stream_len = bulk_len;
if (round_up(stream_len, CHACHA_BLOCK_SIZE) <= req->cryptlen)
stream_len = round_up(stream_len, CHACHA_BLOCK_SIZE);
skcipher_request_set_tfm(&rctx->u.streamcipher_req, tctx->streamcipher);
skcipher_request_set_crypt(&rctx->u.streamcipher_req, req->src,
req->dst, stream_len, &rctx->rbuf);
skcipher_request_set_callback(&rctx->u.streamcipher_req,
req->base.flags,
adiantum_streamcipher_done, req);
return crypto_skcipher_encrypt(&rctx->u.streamcipher_req) ?:
adiantum_finish(req);
}
static int adiantum_encrypt(struct skcipher_request *req)
{
return adiantum_crypt(req, true);
}
static int adiantum_decrypt(struct skcipher_request *req)
{
return adiantum_crypt(req, false);
}
static int adiantum_init_tfm(struct crypto_skcipher *tfm)
{
struct skcipher_instance *inst = skcipher_alg_instance(tfm);
struct adiantum_instance_ctx *ictx = skcipher_instance_ctx(inst);
struct adiantum_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
struct crypto_skcipher *streamcipher;
struct crypto_cipher *blockcipher;
struct crypto_shash *hash;
unsigned int subreq_size;
int err;
streamcipher = crypto_spawn_skcipher(&ictx->streamcipher_spawn);
if (IS_ERR(streamcipher))
return PTR_ERR(streamcipher);
blockcipher = crypto_spawn_cipher(&ictx->blockcipher_spawn);
if (IS_ERR(blockcipher)) {
err = PTR_ERR(blockcipher);
goto err_free_streamcipher;
}
hash = crypto_spawn_shash(&ictx->hash_spawn);
if (IS_ERR(hash)) {
err = PTR_ERR(hash);
goto err_free_blockcipher;
}
tctx->streamcipher = streamcipher;
tctx->blockcipher = blockcipher;
tctx->hash = hash;
BUILD_BUG_ON(offsetofend(struct adiantum_request_ctx, u) !=
sizeof(struct adiantum_request_ctx));
subreq_size = max(sizeof_field(struct adiantum_request_ctx,
u.hash_desc) +
crypto_shash_descsize(hash),
sizeof_field(struct adiantum_request_ctx,
u.streamcipher_req) +
crypto_skcipher_reqsize(streamcipher));
crypto_skcipher_set_reqsize(tfm,
offsetof(struct adiantum_request_ctx, u) +
subreq_size);
return 0;
err_free_blockcipher:
crypto_free_cipher(blockcipher);
err_free_streamcipher:
crypto_free_skcipher(streamcipher);
return err;
}
static void adiantum_exit_tfm(struct crypto_skcipher *tfm)
{
struct adiantum_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
crypto_free_skcipher(tctx->streamcipher);
crypto_free_cipher(tctx->blockcipher);
crypto_free_shash(tctx->hash);
}
static void adiantum_free_instance(struct skcipher_instance *inst)
{
struct adiantum_instance_ctx *ictx = skcipher_instance_ctx(inst);
crypto_drop_skcipher(&ictx->streamcipher_spawn);
crypto_drop_cipher(&ictx->blockcipher_spawn);
crypto_drop_shash(&ictx->hash_spawn);
kfree(inst);
}
/*
* Check for a supported set of inner algorithms.
* See the comment at the beginning of this file.
*/
static bool adiantum_supported_algorithms(struct skcipher_alg_common *streamcipher_alg,
struct crypto_alg *blockcipher_alg,
struct shash_alg *hash_alg)
{
if (strcmp(streamcipher_alg->base.cra_name, "xchacha12") != 0 &&
strcmp(streamcipher_alg->base.cra_name, "xchacha20") != 0)
return false;
if (blockcipher_alg->cra_cipher.cia_min_keysize > BLOCKCIPHER_KEY_SIZE ||
blockcipher_alg->cra_cipher.cia_max_keysize < BLOCKCIPHER_KEY_SIZE)
return false;
if (blockcipher_alg->cra_blocksize != BLOCKCIPHER_BLOCK_SIZE)
return false;
if (strcmp(hash_alg->base.cra_name, "nhpoly1305") != 0)
return false;
return true;
}
static int adiantum_create(struct crypto_template *tmpl, struct rtattr **tb)
{
u32 mask;
const char *nhpoly1305_name;
struct skcipher_instance *inst;
struct adiantum_instance_ctx *ictx;
struct skcipher_alg_common *streamcipher_alg;
struct crypto_alg *blockcipher_alg;
struct shash_alg *hash_alg;
int err;
err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SKCIPHER, &mask);
if (err)
return err;
inst = kzalloc(sizeof(*inst) + sizeof(*ictx), GFP_KERNEL);
if (!inst)
return -ENOMEM;
ictx = skcipher_instance_ctx(inst);
/* Stream cipher, e.g. "xchacha12" */
err = crypto_grab_skcipher(&ictx->streamcipher_spawn,
skcipher_crypto_instance(inst),
crypto_attr_alg_name(tb[1]), 0, mask);
if (err)
goto err_free_inst;
streamcipher_alg = crypto_spawn_skcipher_alg_common(&ictx->streamcipher_spawn);
/* Block cipher, e.g. "aes" */
err = crypto_grab_cipher(&ictx->blockcipher_spawn,
skcipher_crypto_instance(inst),
crypto_attr_alg_name(tb[2]), 0, mask);
if (err)
goto err_free_inst;
blockcipher_alg = crypto_spawn_cipher_alg(&ictx->blockcipher_spawn);
/* NHPoly1305 ε-∆U hash function */
nhpoly1305_name = crypto_attr_alg_name(tb[3]);
if (nhpoly1305_name == ERR_PTR(-ENOENT))
nhpoly1305_name = "nhpoly1305";
err = crypto_grab_shash(&ictx->hash_spawn,
skcipher_crypto_instance(inst),
nhpoly1305_name, 0, mask);
if (err)
goto err_free_inst;
hash_alg = crypto_spawn_shash_alg(&ictx->hash_spawn);
/* Check the set of algorithms */
if (!adiantum_supported_algorithms(streamcipher_alg, blockcipher_alg,
hash_alg)) {
pr_warn("Unsupported Adiantum instantiation: (%s,%s,%s)\n",
streamcipher_alg->base.cra_name,
blockcipher_alg->cra_name, hash_alg->base.cra_name);
err = -EINVAL;
goto err_free_inst;
}
/* Instance fields */
err = -ENAMETOOLONG;
if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
"adiantum(%s,%s)", streamcipher_alg->base.cra_name,
blockcipher_alg->cra_name) >= CRYPTO_MAX_ALG_NAME)
goto err_free_inst;
if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
"adiantum(%s,%s,%s)",
streamcipher_alg->base.cra_driver_name,
blockcipher_alg->cra_driver_name,
hash_alg->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
goto err_free_inst;
inst->alg.base.cra_blocksize = BLOCKCIPHER_BLOCK_SIZE;
inst->alg.base.cra_ctxsize = sizeof(struct adiantum_tfm_ctx);
inst->alg.base.cra_alignmask = streamcipher_alg->base.cra_alignmask;
/*
* The block cipher is only invoked once per message, so for long
* messages (e.g. sectors for disk encryption) its performance doesn't
* matter as much as that of the stream cipher and hash function. Thus,
* weigh the block cipher's ->cra_priority less.
*/
inst->alg.base.cra_priority = (4 * streamcipher_alg->base.cra_priority +
2 * hash_alg->base.cra_priority +
blockcipher_alg->cra_priority) / 7;
inst->alg.setkey = adiantum_setkey;
inst->alg.encrypt = adiantum_encrypt;
inst->alg.decrypt = adiantum_decrypt;
inst->alg.init = adiantum_init_tfm;
inst->alg.exit = adiantum_exit_tfm;
inst->alg.min_keysize = streamcipher_alg->min_keysize;
inst->alg.max_keysize = streamcipher_alg->max_keysize;
inst->alg.ivsize = TWEAK_SIZE;
inst->free = adiantum_free_instance;
err = skcipher_register_instance(tmpl, inst);
if (err) {
err_free_inst:
adiantum_free_instance(inst);
}
return err;
}
/* adiantum(streamcipher_name, blockcipher_name [, nhpoly1305_name]) */
static struct crypto_template adiantum_tmpl = {
.name = "adiantum",
.create = adiantum_create,
.module = THIS_MODULE,
};
static int __init adiantum_module_init(void)
{
return crypto_register_template(&adiantum_tmpl);
}
static void __exit adiantum_module_exit(void)
{
crypto_unregister_template(&adiantum_tmpl);
}
subsys_initcall(adiantum_module_init);
module_exit(adiantum_module_exit);
MODULE_DESCRIPTION("Adiantum length-preserving encryption mode");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Eric Biggers <[email protected]>");
MODULE_ALIAS_CRYPTO("adiantum");
MODULE_IMPORT_NS(CRYPTO_INTERNAL);
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