Commit 71ebc4d1 authored by Martin Willi's avatar Martin Willi Committed by Herbert Xu

crypto: chacha20poly1305 - Add a ChaCha20-Poly1305 AEAD construction, RFC7539

This AEAD uses a chacha20 ablkcipher and a poly1305 ahash to construct the
ChaCha20-Poly1305 AEAD as defined in RFC7539. It supports both synchronous and
asynchronous operations, even if we currently have no async chacha20 or poly1305
drivers.
Signed-off-by: default avatarMartin Willi <martin@strongswan.org>
Acked-by: default avatarSteffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent eee9dc61
......@@ -217,6 +217,18 @@ config CRYPTO_GCM
Support for Galois/Counter Mode (GCM) and Galois Message
Authentication Code (GMAC). Required for IPSec.
config CRYPTO_CHACHA20POLY1305
tristate "ChaCha20-Poly1305 AEAD support"
select CRYPTO_CHACHA20
select CRYPTO_POLY1305
select CRYPTO_AEAD
help
ChaCha20-Poly1305 AEAD support, RFC7539.
Support for the AEAD wrapper using the ChaCha20 stream cipher combined
with the Poly1305 authenticator. It is defined in RFC7539 for use in
IETF protocols.
config CRYPTO_SEQIV
tristate "Sequence Number IV Generator"
select CRYPTO_AEAD
......
......@@ -59,6 +59,7 @@ obj-$(CONFIG_CRYPTO_XTS) += xts.o
obj-$(CONFIG_CRYPTO_CTR) += ctr.o
obj-$(CONFIG_CRYPTO_GCM) += gcm.o
obj-$(CONFIG_CRYPTO_CCM) += ccm.o
obj-$(CONFIG_CRYPTO_CHACHA20POLY1305) += chacha20poly1305.o
obj-$(CONFIG_CRYPTO_PCRYPT) += pcrypt.o
obj-$(CONFIG_CRYPTO_CRYPTD) += cryptd.o
obj-$(CONFIG_CRYPTO_MCRYPTD) += mcryptd.o
......
/*
* ChaCha20-Poly1305 AEAD, RFC7539
*
* Copyright (C) 2015 Martin Willi
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <crypto/internal/aead.h>
#include <crypto/internal/hash.h>
#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include "internal.h"
#define POLY1305_BLOCK_SIZE 16
#define POLY1305_DIGEST_SIZE 16
#define POLY1305_KEY_SIZE 32
#define CHACHA20_KEY_SIZE 32
#define CHACHA20_IV_SIZE 16
#define CHACHAPOLY_IV_SIZE 12
struct chachapoly_instance_ctx {
struct crypto_skcipher_spawn chacha;
struct crypto_ahash_spawn poly;
unsigned int saltlen;
};
struct chachapoly_ctx {
struct crypto_ablkcipher *chacha;
struct crypto_ahash *poly;
/* key bytes we use for the ChaCha20 IV */
unsigned int saltlen;
u8 salt[];
};
struct poly_req {
/* zero byte padding for AD/ciphertext, as needed */
u8 pad[POLY1305_BLOCK_SIZE];
/* tail data with AD/ciphertext lengths */
struct {
__le64 assoclen;
__le64 cryptlen;
} tail;
struct scatterlist src[1];
struct ahash_request req; /* must be last member */
};
struct chacha_req {
/* the key we generate for Poly1305 using Chacha20 */
u8 key[POLY1305_KEY_SIZE];
u8 iv[CHACHA20_IV_SIZE];
struct scatterlist src[1];
struct ablkcipher_request req; /* must be last member */
};
struct chachapoly_req_ctx {
/* calculated Poly1305 tag */
u8 tag[POLY1305_DIGEST_SIZE];
/* length of data to en/decrypt, without ICV */
unsigned int cryptlen;
union {
struct poly_req poly;
struct chacha_req chacha;
} u;
};
static inline void async_done_continue(struct aead_request *req, int err,
int (*cont)(struct aead_request *))
{
if (!err)
err = cont(req);
if (err != -EINPROGRESS && err != -EBUSY)
aead_request_complete(req, err);
}
static void chacha_iv(u8 *iv, struct aead_request *req, u32 icb)
{
struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
__le32 leicb = cpu_to_le32(icb);
memcpy(iv, &leicb, sizeof(leicb));
memcpy(iv + sizeof(leicb), ctx->salt, ctx->saltlen);
memcpy(iv + sizeof(leicb) + ctx->saltlen, req->iv,
CHACHA20_IV_SIZE - sizeof(leicb) - ctx->saltlen);
}
static int poly_verify_tag(struct aead_request *req)
{
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
u8 tag[sizeof(rctx->tag)];
scatterwalk_map_and_copy(tag, req->src, rctx->cryptlen, sizeof(tag), 0);
if (crypto_memneq(tag, rctx->tag, sizeof(tag)))
return -EBADMSG;
return 0;
}
static int poly_copy_tag(struct aead_request *req)
{
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
scatterwalk_map_and_copy(rctx->tag, req->dst, rctx->cryptlen,
sizeof(rctx->tag), 1);
return 0;
}
static void chacha_decrypt_done(struct crypto_async_request *areq, int err)
{
async_done_continue(areq->data, err, poly_verify_tag);
}
static int chacha_decrypt(struct aead_request *req)
{
struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
struct chacha_req *creq = &rctx->u.chacha;
int err;
chacha_iv(creq->iv, req, 1);
ablkcipher_request_set_callback(&creq->req, aead_request_flags(req),
chacha_decrypt_done, req);
ablkcipher_request_set_tfm(&creq->req, ctx->chacha);
ablkcipher_request_set_crypt(&creq->req, req->src, req->dst,
rctx->cryptlen, creq->iv);
err = crypto_ablkcipher_decrypt(&creq->req);
if (err)
return err;
return poly_verify_tag(req);
}
static int poly_tail_continue(struct aead_request *req)
{
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
if (rctx->cryptlen == req->cryptlen) /* encrypting */
return poly_copy_tag(req);
return chacha_decrypt(req);
}
static void poly_tail_done(struct crypto_async_request *areq, int err)
{
async_done_continue(areq->data, err, poly_tail_continue);
}
static int poly_tail(struct aead_request *req)
{
struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
struct poly_req *preq = &rctx->u.poly;
__le64 len;
int err;
sg_init_table(preq->src, 1);
len = cpu_to_le64(req->assoclen);
memcpy(&preq->tail.assoclen, &len, sizeof(len));
len = cpu_to_le64(rctx->cryptlen);
memcpy(&preq->tail.cryptlen, &len, sizeof(len));
sg_set_buf(preq->src, &preq->tail, sizeof(preq->tail));
ahash_request_set_callback(&preq->req, aead_request_flags(req),
poly_tail_done, req);
ahash_request_set_tfm(&preq->req, ctx->poly);
ahash_request_set_crypt(&preq->req, preq->src,
rctx->tag, sizeof(preq->tail));
err = crypto_ahash_finup(&preq->req);
if (err)
return err;
return poly_tail_continue(req);
}
static void poly_cipherpad_done(struct crypto_async_request *areq, int err)
{
async_done_continue(areq->data, err, poly_tail);
}
static int poly_cipherpad(struct aead_request *req)
{
struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
struct poly_req *preq = &rctx->u.poly;
unsigned int padlen, bs = POLY1305_BLOCK_SIZE;
int err;
padlen = (bs - (rctx->cryptlen % bs)) % bs;
memset(preq->pad, 0, sizeof(preq->pad));
sg_init_table(preq->src, 1);
sg_set_buf(preq->src, &preq->pad, padlen);
ahash_request_set_callback(&preq->req, aead_request_flags(req),
poly_cipherpad_done, req);
ahash_request_set_tfm(&preq->req, ctx->poly);
ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen);
err = crypto_ahash_update(&preq->req);
if (err)
return err;
return poly_tail(req);
}
static void poly_cipher_done(struct crypto_async_request *areq, int err)
{
async_done_continue(areq->data, err, poly_cipherpad);
}
static int poly_cipher(struct aead_request *req)
{
struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
struct poly_req *preq = &rctx->u.poly;
struct scatterlist *crypt = req->src;
int err;
if (rctx->cryptlen == req->cryptlen) /* encrypting */
crypt = req->dst;
ahash_request_set_callback(&preq->req, aead_request_flags(req),
poly_cipher_done, req);
ahash_request_set_tfm(&preq->req, ctx->poly);
ahash_request_set_crypt(&preq->req, crypt, NULL, rctx->cryptlen);
err = crypto_ahash_update(&preq->req);
if (err)
return err;
return poly_cipherpad(req);
}
static void poly_adpad_done(struct crypto_async_request *areq, int err)
{
async_done_continue(areq->data, err, poly_cipher);
}
static int poly_adpad(struct aead_request *req)
{
struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
struct poly_req *preq = &rctx->u.poly;
unsigned int padlen, bs = POLY1305_BLOCK_SIZE;
int err;
padlen = (bs - (req->assoclen % bs)) % bs;
memset(preq->pad, 0, sizeof(preq->pad));
sg_init_table(preq->src, 1);
sg_set_buf(preq->src, preq->pad, padlen);
ahash_request_set_callback(&preq->req, aead_request_flags(req),
poly_adpad_done, req);
ahash_request_set_tfm(&preq->req, ctx->poly);
ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen);
err = crypto_ahash_update(&preq->req);
if (err)
return err;
return poly_cipher(req);
}
static void poly_ad_done(struct crypto_async_request *areq, int err)
{
async_done_continue(areq->data, err, poly_adpad);
}
static int poly_ad(struct aead_request *req)
{
struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
struct poly_req *preq = &rctx->u.poly;
int err;
ahash_request_set_callback(&preq->req, aead_request_flags(req),
poly_ad_done, req);
ahash_request_set_tfm(&preq->req, ctx->poly);
ahash_request_set_crypt(&preq->req, req->assoc, NULL, req->assoclen);
err = crypto_ahash_update(&preq->req);
if (err)
return err;
return poly_adpad(req);
}
static void poly_init_done(struct crypto_async_request *areq, int err)
{
async_done_continue(areq->data, err, poly_ad);
}
static int poly_init(struct aead_request *req)
{
struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
struct poly_req *preq = &rctx->u.poly;
int err;
ahash_request_set_callback(&preq->req, aead_request_flags(req),
poly_init_done, req);
ahash_request_set_tfm(&preq->req, ctx->poly);
err = crypto_ahash_init(&preq->req);
if (err)
return err;
return poly_ad(req);
}
static int poly_genkey_continue(struct aead_request *req)
{
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct chachapoly_ctx *ctx = crypto_aead_ctx(aead);
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
struct chacha_req *creq = &rctx->u.chacha;
int err;
crypto_ahash_clear_flags(ctx->poly, CRYPTO_TFM_REQ_MASK);
crypto_ahash_set_flags(ctx->poly, crypto_aead_get_flags(aead) &
CRYPTO_TFM_REQ_MASK);
err = crypto_ahash_setkey(ctx->poly, creq->key, sizeof(creq->key));
crypto_aead_set_flags(aead, crypto_ahash_get_flags(ctx->poly) &
CRYPTO_TFM_RES_MASK);
if (err)
return err;
return poly_init(req);
}
static void poly_genkey_done(struct crypto_async_request *areq, int err)
{
async_done_continue(areq->data, err, poly_genkey_continue);
}
static int poly_genkey(struct aead_request *req)
{
struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
struct chacha_req *creq = &rctx->u.chacha;
int err;
sg_init_table(creq->src, 1);
memset(creq->key, 0, sizeof(creq->key));
sg_set_buf(creq->src, creq->key, sizeof(creq->key));
chacha_iv(creq->iv, req, 0);
ablkcipher_request_set_callback(&creq->req, aead_request_flags(req),
poly_genkey_done, req);
ablkcipher_request_set_tfm(&creq->req, ctx->chacha);
ablkcipher_request_set_crypt(&creq->req, creq->src, creq->src,
POLY1305_KEY_SIZE, creq->iv);
err = crypto_ablkcipher_decrypt(&creq->req);
if (err)
return err;
return poly_genkey_continue(req);
}
static void chacha_encrypt_done(struct crypto_async_request *areq, int err)
{
async_done_continue(areq->data, err, poly_genkey);
}
static int chacha_encrypt(struct aead_request *req)
{
struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
struct chacha_req *creq = &rctx->u.chacha;
int err;
chacha_iv(creq->iv, req, 1);
ablkcipher_request_set_callback(&creq->req, aead_request_flags(req),
chacha_encrypt_done, req);
ablkcipher_request_set_tfm(&creq->req, ctx->chacha);
ablkcipher_request_set_crypt(&creq->req, req->src, req->dst,
req->cryptlen, creq->iv);
err = crypto_ablkcipher_encrypt(&creq->req);
if (err)
return err;
return poly_genkey(req);
}
static int chachapoly_encrypt(struct aead_request *req)
{
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
rctx->cryptlen = req->cryptlen;
/* encrypt call chain:
* - chacha_encrypt/done()
* - poly_genkey/done/continue()
* - poly_init/done()
* - poly_ad/done()
* - poly_adpad/done()
* - poly_cipher/done()
* - poly_cipherpad/done()
* - poly_tail/done/continue()
* - poly_copy_tag()
*/
return chacha_encrypt(req);
}
static int chachapoly_decrypt(struct aead_request *req)
{
struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
if (req->cryptlen < POLY1305_DIGEST_SIZE)
return -EINVAL;
rctx->cryptlen = req->cryptlen - POLY1305_DIGEST_SIZE;
/* decrypt call chain:
* - poly_genkey/done/continue()
* - poly_init/done()
* - poly_ad/done()
* - poly_adpad/done()
* - poly_cipher/done()
* - poly_cipherpad/done()
* - poly_tail/done/continue()
* - chacha_decrypt/done()
* - poly_verify_tag()
*/
return poly_genkey(req);
}
static int chachapoly_setkey(struct crypto_aead *aead, const u8 *key,
unsigned int keylen)
{
struct chachapoly_ctx *ctx = crypto_aead_ctx(aead);
int err;
if (keylen != ctx->saltlen + CHACHA20_KEY_SIZE)
return -EINVAL;
keylen -= ctx->saltlen;
memcpy(ctx->salt, key + keylen, ctx->saltlen);
crypto_ablkcipher_clear_flags(ctx->chacha, CRYPTO_TFM_REQ_MASK);
crypto_ablkcipher_set_flags(ctx->chacha, crypto_aead_get_flags(aead) &
CRYPTO_TFM_REQ_MASK);
err = crypto_ablkcipher_setkey(ctx->chacha, key, keylen);
crypto_aead_set_flags(aead, crypto_ablkcipher_get_flags(ctx->chacha) &
CRYPTO_TFM_RES_MASK);
return err;
}
static int chachapoly_setauthsize(struct crypto_aead *tfm,
unsigned int authsize)
{
if (authsize != POLY1305_DIGEST_SIZE)
return -EINVAL;
return 0;
}
static int chachapoly_init(struct crypto_tfm *tfm)
{
struct crypto_instance *inst = (void *)tfm->__crt_alg;
struct chachapoly_instance_ctx *ictx = crypto_instance_ctx(inst);
struct chachapoly_ctx *ctx = crypto_tfm_ctx(tfm);
struct crypto_ablkcipher *chacha;
struct crypto_ahash *poly;
unsigned long align;
poly = crypto_spawn_ahash(&ictx->poly);
if (IS_ERR(poly))
return PTR_ERR(poly);
chacha = crypto_spawn_skcipher(&ictx->chacha);
if (IS_ERR(chacha)) {
crypto_free_ahash(poly);
return PTR_ERR(chacha);
}
ctx->chacha = chacha;
ctx->poly = poly;
ctx->saltlen = ictx->saltlen;
align = crypto_tfm_alg_alignmask(tfm);
align &= ~(crypto_tfm_ctx_alignment() - 1);
crypto_aead_set_reqsize(__crypto_aead_cast(tfm),
align + offsetof(struct chachapoly_req_ctx, u) +
max(offsetof(struct chacha_req, req) +
sizeof(struct ablkcipher_request) +
crypto_ablkcipher_reqsize(chacha),
offsetof(struct poly_req, req) +
sizeof(struct ahash_request) +
crypto_ahash_reqsize(poly)));
return 0;
}
static void chachapoly_exit(struct crypto_tfm *tfm)
{
struct chachapoly_ctx *ctx = crypto_tfm_ctx(tfm);
crypto_free_ahash(ctx->poly);
crypto_free_ablkcipher(ctx->chacha);
}
static struct crypto_instance *chachapoly_alloc(struct rtattr **tb,
const char *name,
unsigned int ivsize)
{
struct crypto_attr_type *algt;
struct crypto_instance *inst;
struct crypto_alg *chacha;
struct crypto_alg *poly;
struct ahash_alg *poly_ahash;
struct chachapoly_instance_ctx *ctx;
const char *chacha_name, *poly_name;
int err;
if (ivsize > CHACHAPOLY_IV_SIZE)
return ERR_PTR(-EINVAL);
algt = crypto_get_attr_type(tb);
if (IS_ERR(algt))
return ERR_CAST(algt);
if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
return ERR_PTR(-EINVAL);
chacha_name = crypto_attr_alg_name(tb[1]);
if (IS_ERR(chacha_name))
return ERR_CAST(chacha_name);
poly_name = crypto_attr_alg_name(tb[2]);
if (IS_ERR(poly_name))
return ERR_CAST(poly_name);
poly = crypto_find_alg(poly_name, &crypto_ahash_type,
CRYPTO_ALG_TYPE_HASH,
CRYPTO_ALG_TYPE_AHASH_MASK);
if (IS_ERR(poly))
return ERR_CAST(poly);
err = -ENOMEM;
inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
if (!inst)
goto out_put_poly;
ctx = crypto_instance_ctx(inst);
ctx->saltlen = CHACHAPOLY_IV_SIZE - ivsize;
poly_ahash = container_of(poly, struct ahash_alg, halg.base);
err = crypto_init_ahash_spawn(&ctx->poly, &poly_ahash->halg, inst);
if (err)
goto err_free_inst;
crypto_set_skcipher_spawn(&ctx->chacha, inst);
err = crypto_grab_skcipher(&ctx->chacha, chacha_name, 0,
crypto_requires_sync(algt->type,
algt->mask));
if (err)
goto err_drop_poly;
chacha = crypto_skcipher_spawn_alg(&ctx->chacha);
err = -EINVAL;
/* Need 16-byte IV size, including Initial Block Counter value */
if (chacha->cra_ablkcipher.ivsize != CHACHA20_IV_SIZE)
goto out_drop_chacha;
/* Not a stream cipher? */
if (chacha->cra_blocksize != 1)
goto out_drop_chacha;
err = -ENAMETOOLONG;
if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
"%s(%s,%s)", name, chacha_name,
poly_name) >= CRYPTO_MAX_ALG_NAME)
goto out_drop_chacha;
if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
"%s(%s,%s)", name, chacha->cra_driver_name,
poly->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
goto out_drop_chacha;
inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD;
inst->alg.cra_flags |= (chacha->cra_flags |
poly->cra_flags) & CRYPTO_ALG_ASYNC;
inst->alg.cra_priority = (chacha->cra_priority +
poly->cra_priority) / 2;
inst->alg.cra_blocksize = 1;
inst->alg.cra_alignmask = chacha->cra_alignmask | poly->cra_alignmask;
inst->alg.cra_type = &crypto_nivaead_type;
inst->alg.cra_aead.ivsize = ivsize;
inst->alg.cra_aead.maxauthsize = POLY1305_DIGEST_SIZE;
inst->alg.cra_ctxsize = sizeof(struct chachapoly_ctx) + ctx->saltlen;
inst->alg.cra_init = chachapoly_init;
inst->alg.cra_exit = chachapoly_exit;
inst->alg.cra_aead.encrypt = chachapoly_encrypt;
inst->alg.cra_aead.decrypt = chachapoly_decrypt;
inst->alg.cra_aead.setkey = chachapoly_setkey;
inst->alg.cra_aead.setauthsize = chachapoly_setauthsize;
inst->alg.cra_aead.geniv = "seqiv";
out:
crypto_mod_put(poly);
return inst;
out_drop_chacha:
crypto_drop_skcipher(&ctx->chacha);
err_drop_poly:
crypto_drop_ahash(&ctx->poly);
err_free_inst:
kfree(inst);
out_put_poly:
inst = ERR_PTR(err);
goto out;
}
static struct crypto_instance *rfc7539_alloc(struct rtattr **tb)
{
return chachapoly_alloc(tb, "rfc7539", 12);
}
static void chachapoly_free(struct crypto_instance *inst)
{
struct chachapoly_instance_ctx *ctx = crypto_instance_ctx(inst);
crypto_drop_skcipher(&ctx->chacha);
crypto_drop_ahash(&ctx->poly);
kfree(inst);
}
static struct crypto_template rfc7539_tmpl = {
.name = "rfc7539",
.alloc = rfc7539_alloc,
.free = chachapoly_free,
.module = THIS_MODULE,
};
static int __init chacha20poly1305_module_init(void)
{
return crypto_register_template(&rfc7539_tmpl);
}
static void __exit chacha20poly1305_module_exit(void)
{
crypto_unregister_template(&rfc7539_tmpl);
}
module_init(chacha20poly1305_module_init);
module_exit(chacha20poly1305_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
MODULE_DESCRIPTION("ChaCha20-Poly1305 AEAD");
MODULE_ALIAS_CRYPTO("chacha20poly1305");
MODULE_ALIAS_CRYPTO("rfc7539");
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