On 16 October 2018 at 01:54, Eric Biggers <ebiggers@xxxxxxxxxx> wrote: > From: Eric Biggers <ebiggers@xxxxxxxxxx> > > Now that the generic implementation of ChaCha20 has been refactored to > allow varying the number of rounds, add support for XChaCha12, which is > the XSalsa construction applied to ChaCha12. ChaCha12 is one of the > three ciphers specified by the original ChaCha paper > (https://cr.yp.to/chacha/chacha-20080128.pdf: "ChaCha, a variant of > Salsa20"), alongside ChaCha8 and ChaCha20. ChaCha12 is faster than > ChaCha20 but has a lower, but still large, security margin. > > We need XChaCha12 support so that it can be used in the Adiantum > encryption mode, which enables disk/file encryption on low-end mobile > devices where AES-XTS is too slow as the CPUs lack AES instructions. > > We'd prefer XChaCha20 (the more popular variant), but it's too slow on > some of our target devices, so at least in some cases we do need the > XChaCha12-based version. In more detail, the problem is that Adiantum > is still much slower than we're happy with, and encryption still has a > quite noticeable effect on the feel of low-end devices. Users and > vendors push back hard against encryption that degrades the user > experience, which always risks encryption being disabled entirely. So > we need to choose the fastest option that gives us a solid margin of > security, and here that's XChaCha12. The best known attack on ChaCha > breaks only 7 rounds and has 2^235 time complexity, so ChaCha12's > security margin is still better than AES-256's. Much has been learned > about cryptanalysis of ARX ciphers since Salsa20 was originally designed > in 2005, and it now seems we can be comfortable with a smaller number of > rounds. The eSTREAM project also suggests the 12-round version of > Salsa20 as providing the best balance among the different variants: > combining very good performance with a "comfortable margin of security". > > Note that it would be trivial to add vanilla ChaCha12 in addition to > XChaCha12. However, it's unneeded for now and therefore is omitted. > > As discussed in the patch that introduced XChaCha20 support, I > considered splitting the code into separate chacha-common, chacha20, > xchacha20, and xchacha12 modules, so that these algorithms could be > enabled/disabled independently. However, since nearly all the code is > shared anyway, I ultimately decided there would have been little benefit > to the added complexity. > > Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx> One nit below but Reviewed-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> > --- > crypto/Kconfig | 8 +- > crypto/chacha_generic.c | 26 +- > crypto/testmgr.c | 6 + > crypto/testmgr.h | 578 ++++++++++++++++++++++++++++++++++++++++ > include/crypto/chacha.h | 7 + > lib/chacha.c | 6 +- > 6 files changed, 625 insertions(+), 6 deletions(-) > > diff --git a/crypto/Kconfig b/crypto/Kconfig > index d9acbce23d4d5..4fa0a4a0e8615 100644 > --- a/crypto/Kconfig > +++ b/crypto/Kconfig > @@ -1387,10 +1387,10 @@ config CRYPTO_SALSA20 > Bernstein <djb@xxxxxxxx>. See <http://cr.yp.to/snuffle.html> > > config CRYPTO_CHACHA20 > - tristate "ChaCha20 stream cipher algorithms" > + tristate "ChaCha stream cipher algorithms" > select CRYPTO_BLKCIPHER > help > - The ChaCha20 and XChaCha20 stream cipher algorithms. > + The ChaCha20, XChaCha20, and XChaCha12 stream cipher algorithms. > > ChaCha20 is a 256-bit high-speed stream cipher designed by Daniel J. > Bernstein and further specified in RFC7539 for use in IETF protocols. > @@ -1403,6 +1403,10 @@ config CRYPTO_CHACHA20 > while provably retaining ChaCha20's security. See also: > <https://cr.yp.to/snuffle/xsalsa-20081128.pdf> > > + XChaCha12 is XChaCha20 reduced to 12 rounds, with correspondingly > + reduced security margin but increased performance. It can be needed > + in some performance-sensitive scenarios. > + > config CRYPTO_CHACHA20_X86_64 > tristate "ChaCha20 cipher algorithm (x86_64/SSSE3/AVX2)" > depends on X86 && 64BIT > diff --git a/crypto/chacha_generic.c b/crypto/chacha_generic.c > index 8e25e9930c549..8f8f84e51f334 100644 > --- a/crypto/chacha_generic.c > +++ b/crypto/chacha_generic.c > @@ -1,5 +1,5 @@ > /* > - * ChaCha20 (RFC7539) and XChaCha20 stream cipher algorithms > + * ChaCha and XChaCha stream ciphers, including ChaCha20 (RFC7539) > * > * Copyright (C) 2015 Martin Willi > * Copyright (C) 2018 Google LLC > @@ -106,6 +106,13 @@ int crypto_chacha20_setkey(struct crypto_skcipher *tfm, const u8 *key, > } > EXPORT_SYMBOL_GPL(crypto_chacha20_setkey); > > +int crypto_chacha12_setkey(struct crypto_skcipher *tfm, const u8 *key, > + unsigned int keysize) > +{ > + return chacha_setkey(tfm, key, keysize, 12); > +} > +EXPORT_SYMBOL_GPL(crypto_chacha12_setkey); > + > int crypto_chacha_crypt(struct skcipher_request *req) > { > struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); > @@ -168,6 +175,21 @@ static struct skcipher_alg algs[] = { > .setkey = crypto_chacha20_setkey, > .encrypt = crypto_xchacha_crypt, > .decrypt = crypto_xchacha_crypt, > + }, { > + .base.cra_name = "xchacha12", > + .base.cra_driver_name = "xchacha12-generic", > + .base.cra_priority = 100, > + .base.cra_blocksize = 1, > + .base.cra_ctxsize = sizeof(struct chacha_ctx), > + .base.cra_module = THIS_MODULE, > + > + .min_keysize = CHACHA_KEY_SIZE, > + .max_keysize = CHACHA_KEY_SIZE, > + .ivsize = XCHACHA_IV_SIZE, > + .chunksize = CHACHA_BLOCK_SIZE, > + .setkey = crypto_chacha12_setkey, > + .encrypt = crypto_xchacha_crypt, > + .decrypt = crypto_xchacha_crypt, > } > }; > > @@ -191,3 +213,5 @@ MODULE_ALIAS_CRYPTO("chacha20"); > MODULE_ALIAS_CRYPTO("chacha20-generic"); > MODULE_ALIAS_CRYPTO("xchacha20"); > MODULE_ALIAS_CRYPTO("xchacha20-generic"); > +MODULE_ALIAS_CRYPTO("xchacha12"); > +MODULE_ALIAS_CRYPTO("xchacha12-generic"); > diff --git a/crypto/testmgr.c b/crypto/testmgr.c > index a5512e69c8f31..3ff70ebc745cb 100644 > --- a/crypto/testmgr.c > +++ b/crypto/testmgr.c > @@ -3544,6 +3544,12 @@ static const struct alg_test_desc alg_test_descs[] = { > .suite = { > .hash = __VECS(aes_xcbc128_tv_template) > } > + }, { > + .alg = "xchacha12", > + .test = alg_test_skcipher, > + .suite = { > + .cipher = __VECS(xchacha12_tv_template) > + }, > }, { > .alg = "xchacha20", > .test = alg_test_skcipher, > diff --git a/crypto/testmgr.h b/crypto/testmgr.h > index 371641c73cf8c..3b57b2701fcb2 100644 > --- a/crypto/testmgr.h > +++ b/crypto/testmgr.h > @@ -31379,6 +31379,584 @@ static const struct cipher_testvec xchacha20_tv_template[] = { > }, > }; > > +/* > + * Same as XChaCha20 test vectors above, but recomputed the ciphertext with > + * XChaCha12, using a modified libsodium. > + */ > +static const struct cipher_testvec xchacha12_tv_template[] = { > + { > + .key = "\x79\xc9\x97\x98\xac\x67\x30\x0b" > + "\xbb\x27\x04\xc9\x5c\x34\x1e\x32" > + "\x45\xf3\xdc\xb2\x17\x61\xb9\x8e" > + "\x52\xff\x45\xb2\x4f\x30\x4f\xc4", > + .klen = 32, > + .iv = "\xb3\x3f\xfd\x30\x96\x47\x9b\xcf" > + "\xbc\x9a\xee\x49\x41\x76\x88\xa0" > + "\xa2\x55\x4f\x8d\x95\x38\x94\x19" > + "\x00\x00\x00\x00\x00\x00\x00\x00", > + .ptext = "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00", > + .ctext = "\x1b\x78\x7f\xd7\xa1\x41\x68\xab" > + "\x3d\x3f\xd1\x7b\x69\x56\xb2\xd5" > + "\x43\xce\xeb\xaf\x36\xf0\x29\x9d" > + "\x3a\xfb\x18\xae\x1b", > + .len = 29, > + }, { > + .key = "\x9d\x23\xbd\x41\x49\xcb\x97\x9c" > + "\xcf\x3c\x5c\x94\xdd\x21\x7e\x98" > + "\x08\xcb\x0e\x50\xcd\x0f\x67\x81" > + "\x22\x35\xea\xaf\x60\x1d\x62\x32", > + .klen = 32, > + .iv = "\xc0\x47\x54\x82\x66\xb7\xc3\x70" > + "\xd3\x35\x66\xa2\x42\x5c\xbf\x30" > + "\xd8\x2d\x1e\xaf\x52\x94\x10\x9e" > + "\x00\x00\x00\x00\x00\x00\x00\x00", > + .ptext = "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00", > + .ctext = "\xfb\x32\x09\x1d\x83\x05\xae\x4c" > + "\x13\x1f\x12\x71\xf2\xca\xb2\xeb" > + "\x5b\x83\x14\x7d\x83\xf6\x57\x77" > + "\x2e\x40\x1f\x92\x2c\xf9\xec\x35" > + "\x34\x1f\x93\xdf\xfb\x30\xd7\x35" > + "\x03\x05\x78\xc1\x20\x3b\x7a\xe3" > + "\x62\xa3\x89\xdc\x11\x11\x45\xa8" > + "\x82\x89\xa0\xf1\x4e\xc7\x0f\x11" > + "\x69\xdd\x0c\x84\x2b\x89\x5c\xdc" > + "\xf0\xde\x01\xef\xc5\x65\x79\x23" > + "\x87\x67\xd6\x50\xd9\x8d\xd9\x92" > + "\x54\x5b\x0e", > + .len = 91, > + }, { > + .key = "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00", > + .klen = 32, > + .iv = "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x67\xc6\x69\x73" > + "\x51\xff\x4a\xec\x29\xcd\xba\xab" > + "\x00\x00\x00\x00\x00\x00\x00\x00", > + .ptext = "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00", > + .ctext = "\xdf\x2d\xc6\x21\x2a\x9d\xa1\xbb" > + "\xc2\x77\x66\x0c\x5c\x46\xef\xa7" > + "\x79\x1b\xb9\xdf\x55\xe2\xf9\x61" > + "\x4c\x7b\xa4\x52\x24\xaf\xa2\xda" > + "\xd1\x8f\x8f\xa2\x9e\x53\x4d\xc4" > + "\xb8\x55\x98\x08\x7c\x08\xd4\x18" > + "\x67\x8f\xef\x50\xb1\x5f\xa5\x77" > + "\x4c\x25\xe7\x86\x26\x42\xca\x44", > + .len = 64, > + }, { > + .key = "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x00\x00\x00\x00\x01", > + .klen = 32, > + .iv = "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x02\xf2\xfb\xe3\x46" > + "\x7c\xc2\x54\xf8\x1b\xe8\xe7\x8d" > + "\x01\x00\x00\x00\x00\x00\x00\x00", > + .ptext = "\x41\x6e\x79\x20\x73\x75\x62\x6d" > + "\x69\x73\x73\x69\x6f\x6e\x20\x74" > + "\x6f\x20\x74\x68\x65\x20\x49\x45" > + "\x54\x46\x20\x69\x6e\x74\x65\x6e" > + "\x64\x65\x64\x20\x62\x79\x20\x74" > + "\x68\x65\x20\x43\x6f\x6e\x74\x72" > + "\x69\x62\x75\x74\x6f\x72\x20\x66" > + "\x6f\x72\x20\x70\x75\x62\x6c\x69" > + "\x63\x61\x74\x69\x6f\x6e\x20\x61" > + "\x73\x20\x61\x6c\x6c\x20\x6f\x72" > + "\x20\x70\x61\x72\x74\x20\x6f\x66" > + "\x20\x61\x6e\x20\x49\x45\x54\x46" > + "\x20\x49\x6e\x74\x65\x72\x6e\x65" > + "\x74\x2d\x44\x72\x61\x66\x74\x20" > + "\x6f\x72\x20\x52\x46\x43\x20\x61" > + "\x6e\x64\x20\x61\x6e\x79\x20\x73" > + "\x74\x61\x74\x65\x6d\x65\x6e\x74" > + "\x20\x6d\x61\x64\x65\x20\x77\x69" > + "\x74\x68\x69\x6e\x20\x74\x68\x65" > + "\x20\x63\x6f\x6e\x74\x65\x78\x74" > + "\x20\x6f\x66\x20\x61\x6e\x20\x49" > + "\x45\x54\x46\x20\x61\x63\x74\x69" > + "\x76\x69\x74\x79\x20\x69\x73\x20" > + "\x63\x6f\x6e\x73\x69\x64\x65\x72" > + "\x65\x64\x20\x61\x6e\x20\x22\x49" > + "\x45\x54\x46\x20\x43\x6f\x6e\x74" > + "\x72\x69\x62\x75\x74\x69\x6f\x6e" > + "\x22\x2e\x20\x53\x75\x63\x68\x20" > + "\x73\x74\x61\x74\x65\x6d\x65\x6e" > + "\x74\x73\x20\x69\x6e\x63\x6c\x75" > + "\x64\x65\x20\x6f\x72\x61\x6c\x20" > + "\x73\x74\x61\x74\x65\x6d\x65\x6e" > + "\x74\x73\x20\x69\x6e\x20\x49\x45" > + "\x54\x46\x20\x73\x65\x73\x73\x69" > + "\x6f\x6e\x73\x2c\x20\x61\x73\x20" > + "\x77\x65\x6c\x6c\x20\x61\x73\x20" > + "\x77\x72\x69\x74\x74\x65\x6e\x20" > + "\x61\x6e\x64\x20\x65\x6c\x65\x63" > + "\x74\x72\x6f\x6e\x69\x63\x20\x63" > + "\x6f\x6d\x6d\x75\x6e\x69\x63\x61" > + "\x74\x69\x6f\x6e\x73\x20\x6d\x61" > + "\x64\x65\x20\x61\x74\x20\x61\x6e" > + "\x79\x20\x74\x69\x6d\x65\x20\x6f" > + "\x72\x20\x70\x6c\x61\x63\x65\x2c" > + "\x20\x77\x68\x69\x63\x68\x20\x61" > + "\x72\x65\x20\x61\x64\x64\x72\x65" > + "\x73\x73\x65\x64\x20\x74\x6f", > + .ctext = "\xe4\xa6\xc8\x30\xc4\x23\x13\xd6" > + "\x08\x4d\xc9\xb7\xa5\x64\x7c\xb9" > + "\x71\xe2\xab\x3e\xa8\x30\x8a\x1c" > + "\x4a\x94\x6d\x9b\xe0\xb3\x6f\xf1" > + "\xdc\xe3\x1b\xb3\xa9\x6d\x0d\xd6" > + "\xd0\xca\x12\xef\xe7\x5f\xd8\x61" > + "\x3c\x82\xd3\x99\x86\x3c\x6f\x66" > + "\x02\x06\xdc\x55\xf9\xed\xdf\x38" > + "\xb4\xa6\x17\x00\x7f\xef\xbf\x4f" > + "\xf8\x36\xf1\x60\x7e\x47\xaf\xdb" > + "\x55\x9b\x12\xcb\x56\x44\xa7\x1f" > + "\xd3\x1a\x07\x3b\x00\xec\xe6\x4c" > + "\xa2\x43\x27\xdf\x86\x19\x4f\x16" > + "\xed\xf9\x4a\xf3\x63\x6f\xfa\x7f" > + "\x78\x11\xf6\x7d\x97\x6f\xec\x6f" > + "\x85\x0f\x5c\x36\x13\x8d\x87\xe0" > + "\x80\xb1\x69\x0b\x98\x89\x9c\x4e" > + "\xf8\xdd\xee\x5c\x0a\x85\xce\xd4" > + "\xea\x1b\x48\xbe\x08\xf8\xe2\xa8" > + "\xa5\xb0\x3c\x79\xb1\x15\xb4\xb9" > + "\x75\x10\x95\x35\x81\x7e\x26\xe6" > + "\x78\xa4\x88\xcf\xdb\x91\x34\x18" > + "\xad\xd7\x8e\x07\x7d\xab\x39\xf9" > + "\xa3\x9e\xa5\x1d\xbb\xed\x61\xfd" > + "\xdc\xb7\x5a\x27\xfc\xb5\xc9\x10" > + "\xa8\xcc\x52\x7f\x14\x76\x90\xe7" > + "\x1b\x29\x60\x74\xc0\x98\x77\xbb" > + "\xe0\x54\xbb\x27\x49\x59\x1e\x62" > + "\x3d\xaf\x74\x06\xa4\x42\x6f\xc6" > + "\x52\x97\xc4\x1d\xc4\x9f\xe2\xe5" > + "\x38\x57\x91\xd1\xa2\x28\xcc\x40" > + "\xcc\x70\x59\x37\xfc\x9f\x4b\xda" > + "\xa0\xeb\x97\x9a\x7d\xed\x14\x5c" > + "\x9c\xb7\x93\x26\x41\xa8\x66\xdd" > + "\x87\x6a\xc0\xd3\xc2\xa9\x3e\xae" > + "\xe9\x72\xfe\xd1\xb3\xac\x38\xea" > + "\x4d\x15\xa9\xd5\x36\x61\xe9\x96" > + "\x6c\x23\xf8\x43\xe4\x92\x29\xd9" > + "\x8b\x78\xf7\x0a\x52\xe0\x19\x5b" > + "\x59\x69\x5b\x5d\xa1\x53\xc4\x68" > + "\xe1\xbb\xac\x89\x14\xe2\xe2\x85" > + "\x41\x18\xf5\xb3\xd1\xfa\x68\x19" > + "\x44\x78\xdc\xcf\xe7\x88\x2d\x52" > + "\x5f\x40\xb5\x7e\xf8\x88\xa2\xae" > + "\x4a\xb2\x07\x35\x9d\x9b\x07\x88" > + "\xb7\x00\xd0\x0c\xb6\xa0\x47\x59" > + "\xda\x4e\xc9\xab\x9b\x8a\x7b", > + > + .len = 375, > + .also_non_np = 1, > + .np = 3, > + .tap = { 375 - 20, 4, 16 }, > + > + }, { > + .key = "\x1c\x92\x40\xa5\xeb\x55\xd3\x8a" > + "\xf3\x33\x88\x86\x04\xf6\xb5\xf0" > + "\x47\x39\x17\xc1\x40\x2b\x80\x09" > + "\x9d\xca\x5c\xbc\x20\x70\x75\xc0", > + .klen = 32, > + .iv = "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x02\x76\x5a\x2e\x63" > + "\x33\x9f\xc9\x9a\x66\x32\x0d\xb7" > + "\x2a\x00\x00\x00\x00\x00\x00\x00", > + .ptext = "\x27\x54\x77\x61\x73\x20\x62\x72" > + "\x69\x6c\x6c\x69\x67\x2c\x20\x61" > + "\x6e\x64\x20\x74\x68\x65\x20\x73" > + "\x6c\x69\x74\x68\x79\x20\x74\x6f" > + "\x76\x65\x73\x0a\x44\x69\x64\x20" > + "\x67\x79\x72\x65\x20\x61\x6e\x64" > + "\x20\x67\x69\x6d\x62\x6c\x65\x20" > + "\x69\x6e\x20\x74\x68\x65\x20\x77" > + "\x61\x62\x65\x3a\x0a\x41\x6c\x6c" > + "\x20\x6d\x69\x6d\x73\x79\x20\x77" > + "\x65\x72\x65\x20\x74\x68\x65\x20" > + "\x62\x6f\x72\x6f\x67\x6f\x76\x65" > + "\x73\x2c\x0a\x41\x6e\x64\x20\x74" > + "\x68\x65\x20\x6d\x6f\x6d\x65\x20" > + "\x72\x61\x74\x68\x73\x20\x6f\x75" > + "\x74\x67\x72\x61\x62\x65\x2e", > + .ctext = "\xb9\x68\xbc\x6a\x24\xbc\xcc\xd8" > + "\x9b\x2a\x8d\x5b\x96\xaf\x56\xe3" > + "\x11\x61\xe7\xa7\x9b\xce\x4e\x7d" > + "\x60\x02\x48\xac\xeb\xd5\x3a\x26" > + "\x9d\x77\x3b\xb5\x32\x13\x86\x8e" > + "\x20\x82\x26\x72\xae\x64\x1b\x7e" > + "\x2e\x01\x68\xb4\x87\x45\xa1\x24" > + "\xe4\x48\x40\xf0\xaa\xac\xee\xa9" > + "\xfc\x31\xad\x9d\x89\xa3\xbb\xd2" > + "\xe4\x25\x13\xad\x0f\x5e\xdf\x3c" > + "\x27\xab\xb8\x62\x46\x22\x30\x48" > + "\x55\x2c\x4e\x84\x78\x1d\x0d\x34" > + "\x8d\x3c\x91\x0a\x7f\x5b\x19\x9f" > + "\x97\x05\x4c\xa7\x62\x47\x8b\xc5" > + "\x44\x2e\x20\x33\xdd\xa0\x82\xa9" > + "\x25\x76\x37\xe6\x3c\x67\x5b", > + .len = 127, > + }, { > + .key = "\x1c\x92\x40\xa5\xeb\x55\xd3\x8a" > + "\xf3\x33\x88\x86\x04\xf6\xb5\xf0" > + "\x47\x39\x17\xc1\x40\x2b\x80\x09" > + "\x9d\xca\x5c\xbc\x20\x70\x75\xc0", > + .klen = 32, > + .iv = "\x00\x00\x00\x00\x00\x00\x00\x00" > + "\x00\x00\x00\x01\x31\x58\xa3\x5a" > + "\x25\x5d\x05\x17\x58\xe9\x5e\xd4" > + "\x1c\x00\x00\x00\x00\x00\x00\x00", > + .ptext = "\x49\xee\xe0\xdc\x24\x90\x40\xcd" > + "\xc5\x40\x8f\x47\x05\xbc\xdd\x81" > + "\x47\xc6\x8d\xe6\xb1\x8f\xd7\xcb" > + "\x09\x0e\x6e\x22\x48\x1f\xbf\xb8" > + "\x5c\xf7\x1e\x8a\xc1\x23\xf2\xd4" > + "\x19\x4b\x01\x0f\x4e\xa4\x43\xce" > + "\x01\xc6\x67\xda\x03\x91\x18\x90" > + "\xa5\xa4\x8e\x45\x03\xb3\x2d\xac" > + "\x74\x92\xd3\x53\x47\xc8\xdd\x25" > + "\x53\x6c\x02\x03\x87\x0d\x11\x0c" > + "\x58\xe3\x12\x18\xfd\x2a\x5b\x40" > + "\x0c\x30\xf0\xb8\x3f\x43\xce\xae" > + "\x65\x3a\x7d\x7c\xf4\x54\xaa\xcc" > + "\x33\x97\xc3\x77\xba\xc5\x70\xde" > + "\xd7\xd5\x13\xa5\x65\xc4\x5f\x0f" > + "\x46\x1a\x0d\x97\xb5\xf3\xbb\x3c" > + "\x84\x0f\x2b\xc5\xaa\xea\xf2\x6c" > + "\xc9\xb5\x0c\xee\x15\xf3\x7d\xbe" > + "\x9f\x7b\x5a\xa6\xae\x4f\x83\xb6" > + "\x79\x49\x41\xf4\x58\x18\xcb\x86" > + "\x7f\x30\x0e\xf8\x7d\x44\x36\xea" > + "\x75\xeb\x88\x84\x40\x3c\xad\x4f" > + "\x6f\x31\x6b\xaa\x5d\xe5\xa5\xc5" > + "\x21\x66\xe9\xa7\xe3\xb2\x15\x88" > + "\x78\xf6\x79\xa1\x59\x47\x12\x4e" > + "\x9f\x9f\x64\x1a\xa0\x22\x5b\x08" > + "\xbe\x7c\x36\xc2\x2b\x66\x33\x1b" > + "\xdd\x60\x71\xf7\x47\x8c\x61\xc3" > + "\xda\x8a\x78\x1e\x16\xfa\x1e\x86" > + "\x81\xa6\x17\x2a\xa7\xb5\xc2\xe7" > + "\xa4\xc7\x42\xf1\xcf\x6a\xca\xb4" > + "\x45\xcf\xf3\x93\xf0\xe7\xea\xf6" > + "\xf4\xe6\x33\x43\x84\x93\xa5\x67" > + "\x9b\x16\x58\x58\x80\x0f\x2b\x5c" > + "\x24\x74\x75\x7f\x95\x81\xb7\x30" > + "\x7a\x33\xa7\xf7\x94\x87\x32\x27" > + "\x10\x5d\x14\x4c\x43\x29\xdd\x26" > + "\xbd\x3e\x3c\x0e\xfe\x0e\xa5\x10" > + "\xea\x6b\x64\xfd\x73\xc6\xed\xec" > + "\xa8\xc9\xbf\xb3\xba\x0b\x4d\x07" > + "\x70\xfc\x16\xfd\x79\x1e\xd7\xc5" > + "\x49\x4e\x1c\x8b\x8d\x79\x1b\xb1" > + "\xec\xca\x60\x09\x4c\x6a\xd5\x09" > + "\x49\x46\x00\x88\x22\x8d\xce\xea" > + "\xb1\x17\x11\xde\x42\xd2\x23\xc1" > + "\x72\x11\xf5\x50\x73\x04\x40\x47" > + "\xf9\x5d\xe7\xa7\x26\xb1\x7e\xb0" > + "\x3f\x58\xc1\x52\xab\x12\x67\x9d" > + "\x3f\x43\x4b\x68\xd4\x9c\x68\x38" > + "\x07\x8a\x2d\x3e\xf3\xaf\x6a\x4b" > + "\xf9\xe5\x31\x69\x22\xf9\xa6\x69" > + "\xc6\x9c\x96\x9a\x12\x35\x95\x1d" > + "\x95\xd5\xdd\xbe\xbf\x93\x53\x24" > + "\xfd\xeb\xc2\x0a\x64\xb0\x77\x00" > + "\x6f\x88\xc4\x37\x18\x69\x7c\xd7" > + "\x41\x92\x55\x4c\x03\xa1\x9a\x4b" > + "\x15\xe5\xdf\x7f\x37\x33\x72\xc1" > + "\x8b\x10\x67\xa3\x01\x57\x94\x25" > + "\x7b\x38\x71\x7e\xdd\x1e\xcc\x73" > + "\x55\xd2\x8e\xeb\x07\xdd\xf1\xda" > + "\x58\xb1\x47\x90\xfe\x42\x21\x72" > + "\xa3\x54\x7a\xa0\x40\xec\x9f\xdd" > + "\xc6\x84\x6e\xca\xae\xe3\x68\xb4" > + "\x9d\xe4\x78\xff\x57\xf2\xf8\x1b" > + "\x03\xa1\x31\xd9\xde\x8d\xf5\x22" > + "\x9c\xdd\x20\xa4\x1e\x27\xb1\x76" > + "\x4f\x44\x55\xe2\x9b\xa1\x9c\xfe" > + "\x54\xf7\x27\x1b\xf4\xde\x02\xf5" > + "\x1b\x55\x48\x5c\xdc\x21\x4b\x9e" > + "\x4b\x6e\xed\x46\x23\xdc\x65\xb2" > + "\xcf\x79\x5f\x28\xe0\x9e\x8b\xe7" > + "\x4c\x9d\x8a\xff\xc1\xa6\x28\xb8" > + "\x65\x69\x8a\x45\x29\xef\x74\x85" > + "\xde\x79\xc7\x08\xae\x30\xb0\xf4" > + "\xa3\x1d\x51\x41\xab\xce\xcb\xf6" > + "\xb5\xd8\x6d\xe0\x85\xe1\x98\xb3" > + "\x43\xbb\x86\x83\x0a\xa0\xf5\xb7" > + "\x04\x0b\xfa\x71\x1f\xb0\xf6\xd9" > + "\x13\x00\x15\xf0\xc7\xeb\x0d\x5a" > + "\x9f\xd7\xb9\x6c\x65\x14\x22\x45" > + "\x6e\x45\x32\x3e\x7e\x60\x1a\x12" > + "\x97\x82\x14\xfb\xaa\x04\x22\xfa" > + "\xa0\xe5\x7e\x8c\x78\x02\x48\x5d" > + "\x78\x33\x5a\x7c\xad\xdb\x29\xce" > + "\xbb\x8b\x61\xa4\xb7\x42\xe2\xac" > + "\x8b\x1a\xd9\x2f\x0b\x8b\x62\x21" > + "\x83\x35\x7e\xad\x73\xc2\xb5\x6c" > + "\x10\x26\x38\x07\xe5\xc7\x36\x80" > + "\xe2\x23\x12\x61\xf5\x48\x4b\x2b" > + "\xc5\xdf\x15\xd9\x87\x01\xaa\xac" > + "\x1e\x7c\xad\x73\x78\x18\x63\xe0" > + "\x8b\x9f\x81\xd8\x12\x6a\x28\x10" > + "\xbe\x04\x68\x8a\x09\x7c\x1b\x1c" > + "\x83\x66\x80\x47\x80\xe8\xfd\x35" > + "\x1c\x97\x6f\xae\x49\x10\x66\xcc" > + "\xc6\xd8\xcc\x3a\x84\x91\x20\x77" > + "\x72\xe4\x24\xd2\x37\x9f\xc5\xc9" > + "\x25\x94\x10\x5f\x40\x00\x64\x99" > + "\xdc\xae\xd7\x21\x09\x78\x50\x15" > + "\xac\x5f\xc6\x2c\xa2\x0b\xa9\x39" > + "\x87\x6e\x6d\xab\xde\x08\x51\x16" > + "\xc7\x13\xe9\xea\xed\x06\x8e\x2c" > + "\xf8\x37\x8c\xf0\xa6\x96\x8d\x43" > + "\xb6\x98\x37\xb2\x43\xed\xde\xdf" > + "\x89\x1a\xe7\xeb\x9d\xa1\x7b\x0b" > + "\x77\xb0\xe2\x75\xc0\xf1\x98\xd9" > + "\x80\x55\xc9\x34\x91\xd1\x59\xe8" > + "\x4b\x0f\xc1\xa9\x4b\x7a\x84\x06" > + "\x20\xa8\x5d\xfa\xd1\xde\x70\x56" > + "\x2f\x9e\x91\x9c\x20\xb3\x24\xd8" > + "\x84\x3d\xe1\x8c\x7e\x62\x52\xe5" > + "\x44\x4b\x9f\xc2\x93\x03\xea\x2b" > + "\x59\xc5\xfa\x3f\x91\x2b\xbb\x23" > + "\xf5\xb2\x7b\xf5\x38\xaf\xb3\xee" > + "\x63\xdc\x7b\xd1\xff\xaa\x8b\xab" > + "\x82\x6b\x37\x04\xeb\x74\xbe\x79" > + "\xb9\x83\x90\xef\x20\x59\x46\xff" > + "\xe9\x97\x3e\x2f\xee\xb6\x64\x18" > + "\x38\x4c\x7a\x4a\xf9\x61\xe8\x9a" > + "\xa1\xb5\x01\xa6\x47\xd3\x11\xd4" > + "\xce\xd3\x91\x49\x88\xc7\xb8\x4d" > + "\xb1\xb9\x07\x6d\x16\x72\xae\x46" > + "\x5e\x03\xa1\x4b\xb6\x02\x30\xa8" > + "\x3d\xa9\x07\x2a\x7c\x19\xe7\x62" > + "\x87\xe3\x82\x2f\x6f\xe1\x09\xd9" > + "\x94\x97\xea\xdd\x58\x9e\xae\x76" > + "\x7e\x35\xe5\xb4\xda\x7e\xf4\xde" > + "\xf7\x32\x87\xcd\x93\xbf\x11\x56" > + "\x11\xbe\x08\x74\xe1\x69\xad\xe2" > + "\xd7\xf8\x86\x75\x8a\x3c\xa4\xbe" > + "\x70\xa7\x1b\xfc\x0b\x44\x2a\x76" > + "\x35\xea\x5d\x85\x81\xaf\x85\xeb" > + "\xa0\x1c\x61\xc2\xf7\x4f\xa5\xdc" > + "\x02\x7f\xf6\x95\x40\x6e\x8a\x9a" > + "\xf3\x5d\x25\x6e\x14\x3a\x22\xc9" > + "\x37\x1c\xeb\x46\x54\x3f\xa5\x91" > + "\xc2\xb5\x8c\xfe\x53\x08\x97\x32" > + "\x1b\xb2\x30\x27\xfe\x25\x5d\xdc" > + "\x08\x87\xd0\xe5\x94\x1a\xd4\xf1" > + "\xfe\xd6\xb4\xa3\xe6\x74\x81\x3c" > + "\x1b\xb7\x31\xa7\x22\xfd\xd4\xdd" > + "\x20\x4e\x7c\x51\xb0\x60\x73\xb8" > + "\x9c\xac\x91\x90\x7e\x01\xb0\xe1" > + "\x8a\x2f\x75\x1c\x53\x2a\x98\x2a" > + "\x06\x52\x95\x52\xb2\xe9\x25\x2e" > + "\x4c\xe2\x5a\x00\xb2\x13\x81\x03" > + "\x77\x66\x0d\xa5\x99\xda\x4e\x8c" > + "\xac\xf3\x13\x53\x27\x45\xaf\x64" > + "\x46\xdc\xea\x23\xda\x97\xd1\xab" > + "\x7d\x6c\x30\x96\x1f\xbc\x06\x34" > + "\x18\x0b\x5e\x21\x35\x11\x8d\x4c" > + "\xe0\x2d\xe9\x50\x16\x74\x81\xa8" > + "\xb4\x34\xb9\x72\x42\xa6\xcc\xbc" > + "\xca\x34\x83\x27\x10\x5b\x68\x45" > + "\x8f\x52\x22\x0c\x55\x3d\x29\x7c" > + "\xe3\xc0\x66\x05\x42\x91\x5f\x58" > + "\xfe\x4a\x62\xd9\x8c\xa9\x04\x19" > + "\x04\xa9\x08\x4b\x57\xfc\x67\x53" > + "\x08\x7c\xbc\x66\x8a\xb0\xb6\x9f" > + "\x92\xd6\x41\x7c\x5b\x2a\x00\x79" > + "\x72", > + .ctext = "\xe1\xb6\x8b\x5c\x80\xb8\xcc\x08" > + "\x1b\x84\xb2\xd1\xad\xa4\x70\xac" > + "\x67\xa9\x39\x27\xac\xb4\x5b\xb7" > + "\x4c\x26\x77\x23\x1d\xce\x0a\xbe" > + "\x18\x9e\x42\x8b\xbd\x7f\xd6\xf1" > + "\xf1\x6b\xe2\x6d\x7f\x92\x0e\xcb" > + "\xb8\x79\xba\xb4\xac\x7e\x2d\xc0" > + "\x9e\x83\x81\x91\xd5\xea\xc3\x12" > + "\x8d\xa4\x26\x70\xa4\xf9\x71\x0b" > + "\xbd\x2e\xe1\xb3\x80\x42\x25\xb3" > + "\x0b\x31\x99\xe1\x0d\xde\xa6\x90" > + "\xf2\xa3\x10\xf7\xe5\xf3\x83\x1e" > + "\x2c\xfb\x4d\xf0\x45\x3d\x28\x3c" > + "\xb8\xf1\xcb\xbf\x67\xd8\x43\x5a" > + "\x9d\x7b\x73\x29\x88\x0f\x13\x06" > + "\x37\x50\x0d\x7c\xe6\x9b\x07\xdd" > + "\x7e\x01\x1f\x81\x90\x10\x69\xdb" > + "\xa4\xad\x8a\x5e\xac\x30\x72\xf2" > + "\x36\xcd\xe3\x23\x49\x02\x93\xfa" > + "\x3d\xbb\xe2\x98\x83\xeb\xe9\x8d" > + "\xb3\x8f\x11\xaa\x53\xdb\xaf\x2e" > + "\x95\x13\x99\x3d\x71\xbd\x32\x92" > + "\xdd\xfc\x9d\x5e\x6f\x63\x2c\xee" > + "\x91\x1f\x4c\x64\x3d\x87\x55\x0f" > + "\xcc\x3d\x89\x61\x53\x02\x57\x8f" > + "\xe4\x77\x29\x32\xaf\xa6\x2f\x0a" > + "\xae\x3c\x3f\x3f\xf4\xfb\x65\x52" > + "\xc5\xc1\x78\x78\x53\x28\xad\xed" > + "\xd1\x67\x37\xc7\x59\x70\xcd\x0a" > + "\xb8\x0f\x80\x51\x9f\xc0\x12\x5e" > + "\x06\x0a\x7e\xec\x24\x5f\x73\x00" > + "\xb1\x0b\x31\x47\x4f\x73\x8d\xb4" > + "\xce\xf3\x55\x45\x6c\x84\x27\xba" > + "\xb9\x6f\x03\x4a\xeb\x98\x88\x6e" > + "\x53\xed\x25\x19\x0d\x8f\xfe\xca" > + "\x60\xe5\x00\x93\x6e\x3c\xff\x19" > + "\xae\x08\x3b\x8a\xa6\x84\x05\xfe" > + "\x9b\x59\xa0\x8c\xc8\x05\x45\xf5" > + "\x05\x37\xdc\x45\x6f\x8b\x95\x8c" > + "\x4e\x11\x45\x7a\xce\x21\xa5\xf7" > + "\x71\x67\xb9\xce\xd7\xf9\xe9\x5e" > + "\x60\xf5\x53\x7a\xa8\x85\x14\x03" > + "\xa0\x92\xec\xf3\x51\x80\x84\xc4" > + "\xdc\x11\x9e\x57\xce\x4b\x45\xcf" > + "\x90\x95\x85\x0b\x96\xe9\xee\x35" > + "\x10\xb8\x9b\xf2\x59\x4a\xc6\x7e" > + "\x85\xe5\x6f\x38\x51\x93\x40\x0c" > + "\x99\xd7\x7f\x32\xa8\x06\x27\xd1" > + "\x2b\xd5\xb5\x3a\x1a\xe1\x5e\xda" > + "\xcd\x5a\x50\x30\x3c\xc7\xe7\x65" > + "\xa6\x07\x0b\x98\x91\xc6\x20\x27" > + "\x2a\x03\x63\x1b\x1e\x3d\xaf\xc8" > + "\x71\x48\x46\x6a\x64\x28\xf9\x3d" > + "\xd1\x1d\xab\xc8\x40\x76\xc2\x39" > + "\x4e\x00\x75\xd2\x0e\x82\x58\x8c" > + "\xd3\x73\x5a\xea\x46\x89\xbe\xfd" > + "\x4e\x2c\x0d\x94\xaa\x9b\x68\xac" > + "\x86\x87\x30\x7e\xa9\x16\xcd\x59" > + "\xd2\xa6\xbe\x0a\xd8\xf5\xfd\x2d" > + "\x49\x69\xd2\x1a\x90\xd2\x1b\xed" > + "\xff\x71\x04\x87\x87\x21\xc4\xb8" > + "\x1f\x5b\x51\x33\xd0\xd6\x59\x9a" > + "\x03\x0e\xd3\x8b\xfb\x57\x73\xfd" > + "\x5a\x52\x63\x82\xc8\x85\x2f\xcb" > + "\x74\x6d\x4e\xd9\x68\x37\x85\x6a" > + "\xd4\xfb\x94\xed\x8d\xd1\x1a\xaf" > + "\x76\xa7\xb7\x88\xd0\x2b\x4e\xda" > + "\xec\x99\x94\x27\x6f\x87\x8c\xdf" > + "\x4b\x5e\xa6\x66\xdd\xcb\x33\x7b" > + "\x64\x94\x31\xa8\x37\xa6\x1d\xdb" > + "\x0d\x5c\x93\xa4\x40\xf9\x30\x53" > + "\x4b\x74\x8d\xdd\xf6\xde\x3c\xac" > + "\x5c\x80\x01\x3a\xef\xb1\x9a\x02" > + "\x0c\x22\x8e\xe7\x44\x09\x74\x4c" > + "\xf2\x9a\x27\x69\x7f\x12\x32\x36" > + "\xde\x92\xdf\xde\x8f\x5b\x31\xab" > + "\x4a\x01\x26\xe0\xb1\xda\xe8\x37" > + "\x21\x64\xe8\xff\x69\xfc\x9e\x41" > + "\xd2\x96\x2d\x18\x64\x98\x33\x78" > + "\x24\x61\x73\x9b\x47\x29\xf1\xa7" > + "\xcb\x27\x0f\xf0\x85\x6d\x8c\x9d" > + "\x2c\x95\x9e\xe5\xb2\x8e\x30\x29" > + "\x78\x8a\x9d\x65\xb4\x8e\xde\x7b" > + "\xd9\x00\x50\xf5\x7f\x81\xc3\x1b" > + "\x25\x85\xeb\xc2\x8c\x33\x22\x1e" > + "\x68\x38\x22\x30\xd8\x2e\x00\x98" > + "\x85\x16\x06\x56\xb4\x81\x74\x20" > + "\x95\xdb\x1c\x05\x19\xe8\x23\x4d" > + "\x65\x5d\xcc\xd8\x7f\xc4\x2d\x0f" > + "\x57\x26\x71\x07\xad\xaa\x71\x9f" > + "\x19\x76\x2f\x25\x51\x88\xe4\xc0" > + "\x82\x6e\x08\x05\x37\x04\xee\x25" > + "\x23\x90\xe9\x4e\xce\x9b\x16\xc1" > + "\x31\xe7\x6e\x2c\x1b\xe1\x85\x9a" > + "\x0c\x8c\xbb\x12\x1e\x68\x7b\x93" > + "\xa9\x3c\x39\x56\x23\x3e\x6e\xc7" > + "\x77\x84\xd3\xe0\x86\x59\xaa\xb9" > + "\xd5\x53\x58\xc9\x0a\x83\x5f\x85" > + "\xd8\x47\x14\x67\x8a\x3c\x17\xe0" > + "\xab\x02\x51\xea\xf1\xf0\x4f\x30" > + "\x7d\xe0\x92\xc2\x5f\xfb\x19\x5a" > + "\x3f\xbd\xf4\x39\xa4\x31\x0c\x39" > + "\xd1\xae\x4e\xf7\x65\x7f\x1f\xce" > + "\xc2\x39\xd1\x84\xd4\xe5\x02\xe0" > + "\x58\xaa\xf1\x5e\x81\xaf\x7f\x72" > + "\x0f\x08\x99\x43\xb9\xd8\xac\x41" > + "\x35\x55\xf2\xb2\xd4\x98\xb8\x3b" > + "\x2b\x3c\x3e\x16\x06\x31\xfc\x79" > + "\x47\x38\x63\x51\xc5\xd0\x26\xd7" > + "\x43\xb4\x2b\xd9\xc5\x05\xf2\x9d" > + "\x18\xc9\x26\x82\x56\xd2\x11\x05" > + "\xb6\x89\xb4\x43\x9c\xb5\x9d\x11" > + "\x6c\x83\x37\x71\x27\x1c\xae\xbf" > + "\xcd\x57\xd2\xee\x0d\x5a\x15\x26" > + "\x67\x88\x80\x80\x1b\xdc\xc1\x62" > + "\xdd\x4c\xff\x92\x5c\x6c\xe1\xa0" > + "\xe3\x79\xa9\x65\x8c\x8c\x14\x42" > + "\xe5\x11\xd2\x1a\xad\xa9\x56\x6f" > + "\x98\xfc\x8a\x7b\x56\x1f\xc6\xc1" > + "\x52\x12\x92\x9b\x41\x0f\x4b\xae" > + "\x1b\x4a\xbc\xfe\x23\xb6\x94\x70" > + "\x04\x30\x9e\x69\x47\xbe\xb8\x8f" > + "\xca\x45\xd7\x8a\xf4\x78\x3e\xaa" > + "\x71\x17\xd8\x1e\xb8\x11\x8f\xbc" > + "\xc8\x1a\x65\x7b\x41\x89\x72\xc7" > + "\x5f\xbe\xc5\x2a\xdb\x5c\x54\xf9" > + "\x25\xa3\x7a\x80\x56\x9c\x8c\xab" > + "\x26\x19\x10\x36\xa6\xf3\x14\x79" > + "\x40\x98\x70\x68\xb7\x35\xd9\xb9" > + "\x27\xd4\xe7\x74\x5b\x3d\x97\xb4" > + "\xd9\xaa\xd9\xf2\xb5\x14\x84\x1f" > + "\xa9\xde\x12\x44\x5b\x00\xc0\xbc" > + "\xc8\x11\x25\x1b\x67\x7a\x15\x72" > + "\xa6\x31\x6f\xf4\x68\x7a\x86\x9d" > + "\x43\x1c\x5f\x16\xd3\xad\x2e\x52" > + "\xf3\xb4\xc3\xfa\x27\x2e\x68\x6c" > + "\x06\xe7\x4c\x4f\xa2\xe0\xe4\x21" > + "\x5d\x9e\x33\x58\x8d\xbf\xd5\x70" > + "\xf8\x80\xa5\xdd\xe7\x18\x79\xfa" > + "\x7b\xfd\x09\x69\x2c\x37\x32\xa8" > + "\x65\xfa\x8d\x8b\x5c\xcc\xe8\xf3" > + "\x37\xf6\xa6\xc6\x5c\xa2\x66\x79" > + "\xfa\x8a\xa7\xd1\x0b\x2e\x1b\x5e" > + "\x95\x35\x00\x76\xae\x42\xf7\x50" > + "\x51\x78\xfb\xb4\x28\x24\xde\x1a" > + "\x70\x8b\xed\xca\x3c\x5e\xe4\xbd" > + "\x28\xb5\xf3\x76\x4f\x67\x5d\x81" > + "\xb2\x60\x87\xd9\x7b\x19\x1a\xa7" > + "\x79\xa2\xfa\x3f\x9e\xa9\xd7\x25" > + "\x61\xe1\x74\x31\xa2\x77\xa0\x1b" > + "\xf6\xf7\xcb\xc5\xaa\x9e\xce\xf9" > + "\x9b\x96\xef\x51\xc3\x1a\x44\x96" > + "\xae\x17\x50\xab\x29\x08\xda\xcc" > + "\x1a\xb3\x12\xd0\x24\xe4\xe2\xe0" > + "\xc6\xe3\xcc\x82\xd0\xba\x47\x4c" > + "\x3f\x49\xd7\xe8\xb6\x61\xaa\x65" > + "\x25\x18\x40\x2d\x62\x25\x02\x71" > + "\x61\xa2\xc1\xb2\x13\xd2\x71\x3f" > + "\x43\x1a\xc9\x09\x92\xff\xd5\x57" > + "\xf0\xfc\x5e\x1c\xf1\xf5\xf9\xf3" > + "\x5b", > + .len = 1281, > + .also_non_np = 1, > + .np = 3, > + .tap = { 1200, 1, 80 }, > + }, > +}; > + > /* > * CTS (Cipher Text Stealing) mode tests > */ > diff --git a/include/crypto/chacha.h b/include/crypto/chacha.h > index ae79e9983c72f..3d261f5cd156d 100644 > --- a/include/crypto/chacha.h > +++ b/include/crypto/chacha.h > @@ -5,6 +5,11 @@ > * XChaCha extends ChaCha's nonce to 192 bits, while provably retaining ChaCha's > * security. Here they share the same key size, tfm context, and setkey > * function; only their IV size and encrypt/decrypt function differ. > + * > + * The ChaCha paper specifies 20, 12, and 8-round variants. In general, it is > + * recommended to use the 20-round variant ChaCha20. However, the other > + * variants can be needed in some performance-sensitive scenarios. The generic > + * ChaCha code currently allows only the 20 and 12-round variants. > */ > > #ifndef _CRYPTO_CHACHA_H > @@ -39,6 +44,8 @@ void crypto_chacha_init(u32 *state, struct chacha_ctx *ctx, u8 *iv); > > int crypto_chacha20_setkey(struct crypto_skcipher *tfm, const u8 *key, > unsigned int keysize); > +int crypto_chacha12_setkey(struct crypto_skcipher *tfm, const u8 *key, > + unsigned int keysize); > > int crypto_chacha_crypt(struct skcipher_request *req); > int crypto_xchacha_crypt(struct skcipher_request *req); > diff --git a/lib/chacha.c b/lib/chacha.c > index 0a2c2e5b7b84d..c4d69a83fcd2d 100644 > --- a/lib/chacha.c > +++ b/lib/chacha.c > @@ -21,7 +21,7 @@ static void chacha_permute(u32 *x, int nrounds) > int i; > > /* whitelist the allowed round counts */ > - BUG_ON(nrounds != 20); > + BUG_ON(nrounds != 20 && nrounds != 12); > I didn't spot this until this patch, but BUG_ON() may bring down the kernel, and so it should really only be used as a last resort. (i.e., if this is called from non-process context things may explode rather painfully) I didn't look at the entire file [which is a bit cumbersome while reviewing incremental changes like this] and so I don't really have another suggestion right now, but please try to come up with something better if you can. > for (i = 0; i < nrounds; i += 2) { > x[0] += x[4]; x[12] = rol32(x[12] ^ x[0], 16); > @@ -70,7 +70,7 @@ static void chacha_permute(u32 *x, int nrounds) > * chacha_block - generate one keystream block and increment block counter > * @state: input state matrix (16 32-bit words) > * @stream: output keystream block (64 bytes) > - * @nrounds: number of rounds (currently must be 20) > + * @nrounds: number of rounds (20 or 12; 20 is recommended) > * > * This is the ChaCha core, a function from 64-byte strings to 64-byte strings. > * The caller has already converted the endianness of the input. This function > @@ -96,7 +96,7 @@ EXPORT_SYMBOL(chacha_block); > * hchacha_block - abbreviated ChaCha core, for XChaCha > * @in: input state matrix (16 32-bit words) > * @out: output (8 32-bit words) > - * @nrounds: number of rounds (currently must be 20) > + * @nrounds: number of rounds (20 or 12; 20 is recommended) > * > * HChaCha is the ChaCha equivalent of HSalsa and is an intermediate step > * towards XChaCha (see https://cr.yp.to/snuffle/xsalsa-20081128.pdf). HChaCha > -- > 2.19.1.331.ge82ca0e54c-goog > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
