From b168784fa0fd97b17807836b390c79abaadfa8e4 Mon Sep 17 00:00:00 2001 From: Sean Cross Date: Tue, 14 Apr 2020 11:18:45 +0800 Subject: [PATCH] aesio: add basic AES encryption and decryption This adds initial support for an AES module named aesio. This implementation supports only a subset of AES modes, namely ECB, CBC, and CTR modes. Example usage: ``` >>> import aesio >>> >>> key = b'Sixteen byte key' >>> cipher = aesio.AES(key, aesio.MODE_ECB) >>> output = bytearray(16) >>> cipher.encrypt_into(b'Circuit Python!!', output) >>> output bytearray(b'E\x14\x85\x18\x9a\x9c\r\x95>\xa7kV\xa2`\x8b\n') >>> ``` This key is 16-bytes, so it uses AES128. If your key is 24- or 32- bytes long, it will switch to AES192 or AES256 respectively. This has been tested with many of the official NIST test vectors, such as those used in `pycryptodome` at https://github.com/Legrandin/pycryptodome/tree/39626a5b01ce5c1cf51d022be166ad0aea722177/lib/Crypto/SelfTest/Cipher/test_vectors/AES CTR has not been tested as NIST does not provide test vectors for it. Signed-off-by: Sean Cross --- py/circuitpy_defns.mk | 5 + py/circuitpy_mpconfig.h | 8 + py/circuitpy_mpconfig.mk | 3 + shared-bindings/aesio/__init__.c | 79 ++++ shared-bindings/aesio/__init__.h | 53 +++ shared-bindings/aesio/aes.c | 271 ++++++++++++++ shared-module/aesio/__init__.c | 58 +++ shared-module/aesio/__init__.h | 59 +++ shared-module/aesio/aes.c | 608 +++++++++++++++++++++++++++++++ shared-module/aesio/aes.h | 105 ++++++ 10 files changed, 1249 insertions(+) create mode 100644 shared-bindings/aesio/__init__.c create mode 100644 shared-bindings/aesio/__init__.h create mode 100644 shared-bindings/aesio/aes.c create mode 100644 shared-module/aesio/__init__.c create mode 100644 shared-module/aesio/__init__.h create mode 100644 shared-module/aesio/aes.c create mode 100644 shared-module/aesio/aes.h diff --git a/py/circuitpy_defns.mk b/py/circuitpy_defns.mk index ec8e6c3e98..e3892d98e4 100644 --- a/py/circuitpy_defns.mk +++ b/py/circuitpy_defns.mk @@ -99,6 +99,9 @@ endif ### # Select which builtin modules to compile and include. +ifeq ($(CIRCUITPY_AESIO),1) +SRC_PATTERNS += aesio/% +endif ifeq ($(CIRCUITPY_ANALOGIO),1) SRC_PATTERNS += analogio/% endif @@ -341,6 +344,8 @@ SRC_SHARED_MODULE_ALL = \ bitbangio/__init__.c \ board/__init__.c \ busio/OneWire.c \ + aesio/__init__.c \ + aesio/aes.c \ displayio/Bitmap.c \ displayio/ColorConverter.c \ displayio/Display.c \ diff --git a/py/circuitpy_mpconfig.h b/py/circuitpy_mpconfig.h index 29a4d524ca..6b7fc192f9 100644 --- a/py/circuitpy_mpconfig.h +++ b/py/circuitpy_mpconfig.h @@ -223,6 +223,13 @@ typedef long mp_off_t; // These CIRCUITPY_xxx values should all be defined in the *.mk files as being on or off. // So if any are not defined in *.mk, they'll throw an error here. +#if CIRCUITPY_AESIO +extern const struct _mp_obj_module_t aesio_module; +#define AESIO_MODULE { MP_OBJ_NEW_QSTR(MP_QSTR_aesio), (mp_obj_t)&aesio_module }, +#else +#define AESIO_MODULE +#endif + #if CIRCUITPY_ANALOGIO #define ANALOGIO_MODULE { MP_OBJ_NEW_QSTR(MP_QSTR_analogio), (mp_obj_t)&analogio_module }, extern const struct _mp_obj_module_t analogio_module; @@ -619,6 +626,7 @@ extern const struct _mp_obj_module_t ustack_module; // Some of these definitions will be blank depending on what is turned on and off. // Some are omitted because they're in MICROPY_PORT_BUILTIN_MODULE_WEAK_LINKS above. #define MICROPY_PORT_BUILTIN_MODULES_STRONG_LINKS \ + AESIO_MODULE \ ANALOGIO_MODULE \ AUDIOBUSIO_MODULE \ AUDIOCORE_MODULE \ diff --git a/py/circuitpy_mpconfig.mk b/py/circuitpy_mpconfig.mk index c0943230c6..105253aec4 100644 --- a/py/circuitpy_mpconfig.mk +++ b/py/circuitpy_mpconfig.mk @@ -33,6 +33,9 @@ CIRCUITPY_FULL_BUILD ?= 1 CFLAGS += -DCIRCUITPY_FULL_BUILD=$(CIRCUITPY_FULL_BUILD) +CIRCUITPY_AESIO ?= 0 +CFLAGS += -DCIRCUITPY_AESIO=$(CIRCUITPY_AESIO) + CIRCUITPY_ANALOGIO ?= 1 CFLAGS += -DCIRCUITPY_ANALOGIO=$(CIRCUITPY_ANALOGIO) diff --git a/shared-bindings/aesio/__init__.c b/shared-bindings/aesio/__init__.c new file mode 100644 index 0000000000..43dc73e8b1 --- /dev/null +++ b/shared-bindings/aesio/__init__.c @@ -0,0 +1,79 @@ +/* + * This file is part of the MicroPython project, http://micropython.org/ + * + * The MIT License (MIT) + * + * Copyright (c) 2017 Scott Shawcroft for Adafruit Industries + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#include + +#include "py/obj.h" +#include "py/runtime.h" + +#include "__init__.h" + +//| :mod:`aesio` --- AES encryption routines +//| ======================================== +//| +//| .. module:: aesio +//| :synopsis: Embedded implementation of AES +//| +//| The `AES` module contains classes used to implement encryption +//| and decryption. It aims to be low overhead in terms of memory. +//| +//| + +//| Libraries +//| +//| .. toctree:: +//| :maxdepth: 3 +//| +//| aes + + +STATIC const mp_obj_tuple_t mp_aes_key_size_obj = { + {&mp_type_tuple}, + 3, + { + MP_OBJ_NEW_SMALL_INT(16), + MP_OBJ_NEW_SMALL_INT(24), + MP_OBJ_NEW_SMALL_INT(32), + } +}; + +STATIC const mp_rom_map_elem_t aesio_module_globals_table[] = { + {MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_aesio)}, + {MP_ROM_QSTR(MP_QSTR_AES), MP_ROM_PTR(&aesio_aes_type) }, + {MP_ROM_QSTR(MP_QSTR_MODE_ECB), MP_ROM_INT(AES_MODE_ECB)}, + {MP_ROM_QSTR(MP_QSTR_MODE_CBC), MP_ROM_INT(AES_MODE_CBC)}, + {MP_ROM_QSTR(MP_QSTR_MODE_CTR), MP_ROM_INT(AES_MODE_CTR)}, + {MP_ROM_QSTR(MP_QSTR_block_size), MP_ROM_INT(AES_BLOCKLEN)}, + {MP_ROM_QSTR(MP_QSTR_key_size), (mp_obj_t)&mp_aes_key_size_obj}, +}; + +STATIC MP_DEFINE_CONST_DICT(aesio_module_globals, aesio_module_globals_table); + +const mp_obj_module_t aesio_module = { + .base = {&mp_type_module}, + .globals = (mp_obj_dict_t *)&aesio_module_globals, +}; + diff --git a/shared-bindings/aesio/__init__.h b/shared-bindings/aesio/__init__.h new file mode 100644 index 0000000000..634fed2e54 --- /dev/null +++ b/shared-bindings/aesio/__init__.h @@ -0,0 +1,53 @@ +/* + * This file is part of the Micro Python project, http://micropython.org/ + * + * The MIT License (MIT) + * + * Copyright (c) 2017 Scott Shawcroft for Adafruit Industries + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#ifndef MICROPY_INCLUDED_SHARED_BINDINGS_AESIO_H +#define MICROPY_INCLUDED_SHARED_BINDINGS_AESIO_H + +#include "shared-module/aesio/__init__.h" + +extern const mp_obj_type_t aesio_aes_type; + +void common_hal_aesio_aes_construct(aesio_aes_obj_t* self, + const uint8_t* key, + uint32_t key_length, + const uint8_t* iv, + int mode, + int counter); +void common_hal_aesio_aes_rekey(aesio_aes_obj_t* self, + const uint8_t* key, + uint32_t key_length, + const uint8_t* iv); +void common_hal_aesio_aes_set_mode(aesio_aes_obj_t* self, + int mode); +void common_hal_aesio_aes_encrypt(aesio_aes_obj_t* self, + uint8_t* buffer, + size_t len); +void common_hal_aesio_aes_decrypt(aesio_aes_obj_t* self, + uint8_t* buffer, + size_t len); + +#endif // MICROPY_INCLUDED_SHARED_BINDINGS_AESIO_H diff --git a/shared-bindings/aesio/aes.c b/shared-bindings/aesio/aes.c new file mode 100644 index 0000000000..4ddcfa898b --- /dev/null +++ b/shared-bindings/aesio/aes.c @@ -0,0 +1,271 @@ +#include +#include + +#include "py/obj.h" +#include "py/objproperty.h" +#include "py/runtime.h" + +#include "shared-bindings/aesio/__init__.h" + +// Defined at the end of this file + +//| .. currentmodule:: aesio +//| +//| :class:`aesio` -- Encrypt and decrypt AES streams +//| ===================================================== +//| +//| An object that represents an AES stream, including the current state. +//| +//| .. class:: AES(key, mode=0, iv=None, segment_size=8) +//| +//| Create a new AES state with the given key. +//| +//| :param bytearray key: A 16-, 24-, or 32-byte key +//| :param int mode: AES mode to use. One of: AES.MODE_ECB, AES.MODE_CBC, or +//| AES.MODE_CTR +//| :param bytearray iv: Initialization vector to use for CBC or CTR mode +//| +//| Additional arguments are supported for legacy reasons. +//| +//| Encrypting a string:: +//| +//| import aesio +//| from binascii import hexlify +//| +//| key = b'Sixteen byte key' +//| inp = b'Circuit Python!!' # Note: 16-bytes long +//| outp = bytearray(len(inp)) +//| cipher = aesio.AES(key, aesio.mode.MODE_ECB) +//| cipher.encrypt_into(inp, outp) +//| hexlify(outp) +//| + +STATIC mp_obj_t aesio_aes_make_new(const mp_obj_type_t *type, size_t n_args, + const mp_obj_t *pos_args, + mp_map_t *kw_args) { + (void)type; + enum { ARG_key, ARG_mode, ARG_IV, ARG_counter, ARG_segment_size }; + static const mp_arg_t allowed_args[] = { + {MP_QSTR_key, MP_ARG_OBJ | MP_ARG_REQUIRED}, + {MP_QSTR_mode, MP_ARG_INT, {.u_int = AES_MODE_ECB}}, + {MP_QSTR_IV, MP_ARG_OBJ}, + {MP_QSTR_counter, MP_ARG_OBJ}, + {MP_QSTR_segment_size, MP_ARG_INT, {.u_int = 8}}, + }; + mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)]; + + mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), + allowed_args, args); + + aesio_aes_obj_t *self = m_new_obj(aesio_aes_obj_t); + self->base.type = &aesio_aes_type; + + mp_buffer_info_t bufinfo; + + const uint8_t *key = NULL; + uint32_t key_length = 0; + if (mp_get_buffer(args[ARG_key].u_obj, &bufinfo, MP_BUFFER_READ)) { + if ((bufinfo.len != 16) && (bufinfo.len != 24) && (bufinfo.len != 32)) { + mp_raise_TypeError(translate("Key must be 16, 24, or 32 bytes long")); + } + key = bufinfo.buf; + key_length = bufinfo.len; + } else { + mp_raise_TypeError(translate("No key was specified")); + } + + int mode = args[ARG_mode].u_int; + switch (args[ARG_mode].u_int) { + case AES_MODE_CBC: + case AES_MODE_ECB: + case AES_MODE_CTR: + break; + default: + mp_raise_TypeError(translate("Requested AES mode is unsupported")); + } + + // IV is required for CBC mode and is ignored for other modes. + const uint8_t *iv = NULL; + if (args[ARG_IV].u_obj != NULL && + mp_get_buffer(args[ARG_IV].u_obj, &bufinfo, MP_BUFFER_READ)) { + if (bufinfo.len != AES_BLOCKLEN) { + mp_raise_TypeError_varg(translate("IV must be %d bytes long"), + AES_BLOCKLEN); + } + iv = bufinfo.buf; + } + + common_hal_aesio_aes_construct(self, key, key_length, iv, mode, + args[ARG_counter].u_int); + return MP_OBJ_FROM_PTR(self); +} + +STATIC mp_obj_t aesio_aes_rekey(size_t n_args, const mp_obj_t *pos_args) { + aesio_aes_obj_t *self = MP_OBJ_TO_PTR(pos_args[0]); + + size_t key_length = 0; + const uint8_t *key = + (const uint8_t *)mp_obj_str_get_data(pos_args[1], &key_length); + if (key == NULL) { + mp_raise_ValueError(translate("No key was specified")); + } + if ((key_length != 16) && (key_length != 24) && (key_length != 32)) { + mp_raise_TypeError(translate("Key must be 16, 24, or 32 bytes long")); + } + + const uint8_t *iv = NULL; + if (n_args > 2) { + size_t iv_length = 0; + iv = (const uint8_t *)mp_obj_str_get_data(pos_args[2], &iv_length); + if (iv_length != AES_BLOCKLEN) { + mp_raise_TypeError_varg(translate("IV must be %d bytes long"), + AES_BLOCKLEN); + } + } + + common_hal_aesio_aes_rekey(self, key, key_length, iv); + return mp_const_none; +} + +MP_DEFINE_CONST_FUN_OBJ_VAR(aesio_aes_rekey_obj, 2, aesio_aes_rekey); + +STATIC void validate_length(aesio_aes_obj_t *self, size_t src_length, + size_t dest_length) { + if (src_length != dest_length) { + mp_raise_ValueError( + translate("Source and destination buffers must be the same length")); + } + + switch (self->mode) { + case AES_MODE_ECB: + if (src_length != 16) { + mp_raise_msg(&mp_type_ValueError, + translate("ECB only operates on 16 bytes at a time")); + } + break; + case AES_MODE_CBC: + if ((src_length & 15) != 0) { + mp_raise_msg(&mp_type_ValueError, + translate("CBC blocks must be multiples of 16 bytes")); + } + break; + case AES_MODE_CTR: + break; + } +} + +//| .. method:: encrypt_into(src, dest) +//| +//| Encrypt the buffer from ``src`` into ``dest``. +//| For ECB mode, the buffers must be 16 bytes long. For CBC mode, the +//| buffers must be a multiple of 16 bytes, and must be equal length. For +//| CTX mode, there are no restrictions. +//| +STATIC mp_obj_t aesio_aes_encrypt_into(mp_obj_t aesio_obj, mp_obj_t src, + mp_obj_t dest) { + if (!MP_OBJ_IS_TYPE(aesio_obj, &aesio_aes_type)) { + mp_raise_TypeError_varg(translate("Expected a %q"), aesio_aes_type.name); + } + // Convert parameters into expected types. + aesio_aes_obj_t *aes = MP_OBJ_TO_PTR(aesio_obj); + + mp_buffer_info_t srcbufinfo, destbufinfo; + mp_get_buffer_raise(src, &srcbufinfo, MP_BUFFER_READ); + mp_get_buffer_raise(dest, &destbufinfo, MP_BUFFER_READ); + validate_length(aes, srcbufinfo.len, destbufinfo.len); + + memcpy(destbufinfo.buf, srcbufinfo.buf, srcbufinfo.len); + + common_hal_aesio_aes_encrypt(aes, (uint8_t *)destbufinfo.buf, + destbufinfo.len); + return mp_const_none; +} + +STATIC MP_DEFINE_CONST_FUN_OBJ_3(aesio_aes_encrypt_into_obj, + aesio_aes_encrypt_into); + +//| .. method:: decrypt_into(src, dest) +//| +//| Decrypt the buffer from ``src`` into ``dest``. +//| For ECB mode, the buffers must be 16 bytes long. For CBC mode, the +//| buffers must be a multiple of 16 bytes, and must be equal length. For +//| CTX mode, there are no restrictions. +//| +STATIC mp_obj_t aesio_aes_decrypt_into(mp_obj_t aesio_obj, mp_obj_t src, + mp_obj_t dest) { + if (!MP_OBJ_IS_TYPE(aesio_obj, &aesio_aes_type)) { + mp_raise_TypeError_varg(translate("Expected a %q"), aesio_aes_type.name); + } + // Convert parameters into expected types. + aesio_aes_obj_t *aes = MP_OBJ_TO_PTR(aesio_obj); + + mp_buffer_info_t srcbufinfo, destbufinfo; + mp_get_buffer_raise(src, &srcbufinfo, MP_BUFFER_READ); + mp_get_buffer_raise(dest, &destbufinfo, MP_BUFFER_READ); + validate_length(aes, srcbufinfo.len, destbufinfo.len); + + memcpy(destbufinfo.buf, srcbufinfo.buf, srcbufinfo.len); + + common_hal_aesio_aes_decrypt(aes, (uint8_t *)destbufinfo.buf, + destbufinfo.len); + return mp_const_none; +} + +STATIC MP_DEFINE_CONST_FUN_OBJ_3(aesio_aes_decrypt_into_obj, + aesio_aes_decrypt_into); + +STATIC mp_obj_t aesio_aes_get_mode(mp_obj_t aesio_obj) { + if (!MP_OBJ_IS_TYPE(aesio_obj, &aesio_aes_type)) { + mp_raise_TypeError_varg(translate("Expected a %q"), aesio_aes_type.name); + } + aesio_aes_obj_t *self = MP_OBJ_TO_PTR(aesio_obj); + return MP_OBJ_NEW_SMALL_INT(self->mode); +} +MP_DEFINE_CONST_FUN_OBJ_1(aesio_aes_get_mode_obj, aesio_aes_get_mode); + +STATIC mp_obj_t aesio_aes_set_mode(mp_obj_t aesio_obj, mp_obj_t mode_obj) { + if (!MP_OBJ_IS_TYPE(aesio_obj, &aesio_aes_type)) { + mp_raise_TypeError_varg(translate("Expected a %q"), aesio_aes_type.name); + } + aesio_aes_obj_t *self = MP_OBJ_TO_PTR(aesio_obj); + + int mode = mp_obj_get_int(mode_obj); + switch (mode) { + case AES_MODE_CBC: + case AES_MODE_ECB: + case AES_MODE_CTR: + break; + default: + mp_raise_TypeError(translate("Requested AES mode is unsupported")); + } + + common_hal_aesio_aes_set_mode(self, mode); + return mp_const_none; +} +MP_DEFINE_CONST_FUN_OBJ_2(aesio_aes_set_mode_obj, aesio_aes_set_mode); + +const mp_obj_property_t aesio_aes_mode_obj = { + .base.type = &mp_type_property, + .proxy = { + (mp_obj_t)&aesio_aes_get_mode_obj, + (mp_obj_t)&aesio_aes_set_mode_obj, + (mp_obj_t)&mp_const_none_obj + }, +}; + +STATIC const mp_rom_map_elem_t aesio_locals_dict_table[] = { + // Methods + {MP_ROM_QSTR(MP_QSTR___name__), MP_OBJ_NEW_QSTR(MP_QSTR_AES)}, + {MP_ROM_QSTR(MP_QSTR_encrypt_into), (mp_obj_t)&aesio_aes_encrypt_into_obj}, + {MP_ROM_QSTR(MP_QSTR_decrypt_into), (mp_obj_t)&aesio_aes_decrypt_into_obj}, + {MP_ROM_QSTR(MP_QSTR_rekey), (mp_obj_t)&aesio_aes_rekey_obj}, + {MP_ROM_QSTR(MP_QSTR_mode), (mp_obj_t)&aesio_aes_mode_obj}, +}; +STATIC MP_DEFINE_CONST_DICT(aesio_locals_dict, aesio_locals_dict_table); + +const mp_obj_type_t aesio_aes_type = { + {&mp_type_type}, + .name = MP_QSTR_AES, + .make_new = aesio_aes_make_new, + .locals_dict = (mp_obj_dict_t *)&aesio_locals_dict, +}; diff --git a/shared-module/aesio/__init__.c b/shared-module/aesio/__init__.c new file mode 100644 index 0000000000..2cacaeb66e --- /dev/null +++ b/shared-module/aesio/__init__.c @@ -0,0 +1,58 @@ +#include + +#include "py/runtime.h" + +#include "shared-bindings/aesio/__init__.h" +#include "shared-module/aesio/__init__.h" + +void common_hal_aesio_aes_construct(aesio_aes_obj_t *self, const uint8_t *key, + uint32_t key_length, const uint8_t *iv, + int mode, int counter) { + self->mode = mode; + self->counter = counter; + common_hal_aesio_aes_rekey(self, key, key_length, iv); +} + +void common_hal_aesio_aes_rekey(aesio_aes_obj_t *self, const uint8_t *key, + uint32_t key_length, const uint8_t *iv) { + memset(&self->ctx, 0, sizeof(self->ctx)); + if (iv != NULL) { + AES_init_ctx_iv(&self->ctx, key, key_length, iv); + } else { + AES_init_ctx(&self->ctx, key, key_length); + } +} + +void common_hal_aesio_aes_set_mode(aesio_aes_obj_t *self, int mode) { + self->mode = mode; +} + +void common_hal_aesio_aes_encrypt(aesio_aes_obj_t *self, uint8_t *buffer, + size_t length) { + switch (self->mode) { + case AES_MODE_ECB: + AES_ECB_encrypt(&self->ctx, buffer); + break; + case AES_MODE_CBC: + AES_CBC_encrypt_buffer(&self->ctx, buffer, length); + break; + case AES_MODE_CTR: + AES_CTR_xcrypt_buffer(&self->ctx, buffer, length); + break; + } +} + +void common_hal_aesio_aes_decrypt(aesio_aes_obj_t *self, uint8_t *buffer, + size_t length) { + switch (self->mode) { + case AES_MODE_ECB: + AES_ECB_decrypt(&self->ctx, buffer); + break; + case AES_MODE_CBC: + AES_CBC_decrypt_buffer(&self->ctx, buffer, length); + break; + case AES_MODE_CTR: + AES_CTR_xcrypt_buffer(&self->ctx, buffer, length); + break; + } +} diff --git a/shared-module/aesio/__init__.h b/shared-module/aesio/__init__.h new file mode 100644 index 0000000000..1a0bb86967 --- /dev/null +++ b/shared-module/aesio/__init__.h @@ -0,0 +1,59 @@ +/* + * This file is part of the MicroPython project, http://micropython.org/ + * + * The MIT License (MIT) + * + * Copyright (c) 2018 Dan Halbert for Adafruit Industries + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#ifndef MICROPY_INCLUDED_SHARED_MODULE_AESIO__INIT__H +#define MICROPY_INCLUDED_SHARED_MODULE_AESIO__INIT__H + +#include +#include + +#include "py/obj.h" +#include "py/proto.h" + +#include "shared-module/aesio/aes.h" + +// These values were chosen to correspond with the values +// present in pycrypto. +enum AES_MODE { + AES_MODE_ECB = 1, + AES_MODE_CBC = 2, + AES_MODE_CTR = 6, +}; + +typedef struct { + mp_obj_base_t base; + + // The tinyaes context + struct AES_ctx ctx; + + // Which AES mode this instance of the object is configured to use + enum AES_MODE mode; + + // Counter for running in CTR mode + uint32_t counter; +} aesio_aes_obj_t; + +#endif // MICROPY_INCLUDED_SHARED_MODULE_AESIO__INIT__H diff --git a/shared-module/aesio/aes.c b/shared-module/aesio/aes.c new file mode 100644 index 0000000000..b62b5afc48 --- /dev/null +++ b/shared-module/aesio/aes.c @@ -0,0 +1,608 @@ +/* + +This is an implementation of the AES algorithm, specifically ECB, CTR and CBC mode. +Block size can be chosen in aes.h - available choices are AES128, AES192, AES256. + +The implementation is verified against the test vectors in: + National Institute of Standards and Technology Special Publication 800-38A 2001 ED + +ECB-AES128 +---------- + + plain-text: + 6bc1bee22e409f96e93d7e117393172a + ae2d8a571e03ac9c9eb76fac45af8e51 + 30c81c46a35ce411e5fbc1191a0a52ef + f69f2445df4f9b17ad2b417be66c3710 + + key: + 2b7e151628aed2a6abf7158809cf4f3c + + resulting cipher + 3ad77bb40d7a3660a89ecaf32466ef97 + f5d3d58503b9699de785895a96fdbaaf + 43b1cd7f598ece23881b00e3ed030688 + 7b0c785e27e8ad3f8223207104725dd4 + + +NOTE: String length must be evenly divisible by 16byte (str_len % 16 == 0) + You should pad the end of the string with zeros if this is not the case. + For AES192/256 the key size is proportionally larger. + +*/ + +/*****************************************************************************/ +/* Includes: */ +/*****************************************************************************/ +#include // CBC mode, for memset +#include "aes.h" + +/*****************************************************************************/ +/* Defines: */ +/*****************************************************************************/ +// The number of columns comprising a state in AES. This is a constant in AES. +// Value=4 +#define Nb 4UL + +#if defined(AES256) && (AES256 == 1) + #define Nk256 8UL + #define Nr256 14UL +#endif +#if defined(AES192) && (AES192 == 1) + #define Nk192 6UL + #define Nr192 12UL +#endif +#if defined(AES128) && (AES128 == 1) + #define Nk128 4UL // The number of 32 bit words in a key. + #define Nr128 10UL // The number of rounds in AES Cipher. +#endif + +// jcallan@github points out that declaring Multiply as a function reduces code +// size considerably with the Keil ARM compiler. See this link for more +// information: https://github.com/kokke/tiny-AES-C/pull/3 +#ifndef MULTIPLY_AS_A_FUNCTION + #define MULTIPLY_AS_A_FUNCTION 0 +#endif + + + + +/*****************************************************************************/ +/* Private variables: */ +/*****************************************************************************/ +// state - array holding the intermediate results during decryption. +typedef uint8_t state_t[4][4]; + + + +// The lookup-tables are marked const so they can be placed in read-only storage +// instead of RAM The numbers below can be computed dynamically trading ROM for +// RAM - This can be useful in (embedded) bootloader applications, where ROM is +// often limited. +static const uint8_t sbox[256] = { + //0 1 2 3 4 5 6 7 8 9 A B C D E F + 0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76, + 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, + 0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15, + 0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75, + 0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84, + 0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf, + 0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8, + 0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, + 0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73, + 0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb, + 0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, + 0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08, + 0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a, + 0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e, + 0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf, + 0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16 }; + +static const uint8_t rsbox[256] = { + 0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb, + 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb, + 0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e, + 0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25, + 0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92, + 0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84, + 0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06, + 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b, + 0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73, + 0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e, + 0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b, + 0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4, + 0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f, + 0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef, + 0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61, + 0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d }; + +// The round constant word array, Rcon[i], contains the values given by x to the +// power (i-1) being powers of x (x is denoted as {02}) in the field GF(2^8) +static const uint8_t Rcon[11] = { + 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36 }; + +/* + * Jordan Goulder points out in PR #12 + * (https://github.com/kokke/tiny-AES-C/pull/12), that you can remove most of + * the elements in the Rcon array, because they are unused. + * + * From Wikipedia's article on the Rijndael key schedule @ + * https://en.wikipedia.org/wiki/Rijndael_key_schedule#Rcon + * + * "Only the first some of these constants are actually used – up to rcon[10] + * for AES-128 (as 11 round keys are needed), up to rcon[8] for AES-192, up to + * rcon[7] for AES-256. rcon[0] is not used in AES algorithm." + */ + + +/*****************************************************************************/ +/* Private functions: */ +/*****************************************************************************/ +static const uint8_t *GetRoundKey(const struct AES_ctx *ctx) { + switch (ctx->KeyLength) { +#if defined(AES128) && (AES128 == 1) + case 16: return ctx->RoundKey128; +#endif +#if defined(AES192) && (AES192 == 1) + case 24: return ctx->RoundKey192; +#endif +#if defined(AES256) && (AES256 == 1) + case 32: return ctx->RoundKey256; +#endif + } + return NULL; +} + + +/* +static uint8_t getSBoxValue(uint8_t num) +{ + return sbox[num]; +} +*/ +#define getSBoxValue(num) (sbox[(num)]) +/* +static uint8_t getSBoxInvert(uint8_t num) +{ + return rsbox[num]; +} +*/ +#define getSBoxInvert(num) (rsbox[(num)]) + +// This function produces Nb(Nr+1) round keys. The round keys are used in each +// round to decrypt the states. +static void KeyExpansion(struct AES_ctx* ctx, const uint8_t* Key) +{ + uint8_t* RoundKey = (uint8_t *)GetRoundKey(ctx); + + unsigned i, j, k; + uint8_t tempa[4]; // Used for the column/row operations + + // The first round key is the key itself. + for (i = 0; i < ctx->Nk; ++i) + { + RoundKey[(i * 4) + 0] = Key[(i * 4) + 0]; + RoundKey[(i * 4) + 1] = Key[(i * 4) + 1]; + RoundKey[(i * 4) + 2] = Key[(i * 4) + 2]; + RoundKey[(i * 4) + 3] = Key[(i * 4) + 3]; + } + + // All other round keys are found from the previous round keys. + for (i = ctx->Nk; i < Nb * (ctx->Nr + 1); ++i) + { + { + k = (i - 1) * 4; + tempa[0]=RoundKey[k + 0]; + tempa[1]=RoundKey[k + 1]; + tempa[2]=RoundKey[k + 2]; + tempa[3]=RoundKey[k + 3]; + + } + + if (i % ctx->Nk == 0) + { + // This function shifts the 4 bytes in a word to the left once. + // [a0,a1,a2,a3] becomes [a1,a2,a3,a0] + + // Function RotWord() + { + const uint8_t u8tmp = tempa[0]; + tempa[0] = tempa[1]; + tempa[1] = tempa[2]; + tempa[2] = tempa[3]; + tempa[3] = u8tmp; + } + + // SubWord() is a function that takes a four-byte input word and applies + // the S-box to each of the four bytes to produce an output word. + + // Function Subword() + { + tempa[0] = getSBoxValue(tempa[0]); + tempa[1] = getSBoxValue(tempa[1]); + tempa[2] = getSBoxValue(tempa[2]); + tempa[3] = getSBoxValue(tempa[3]); + } + + tempa[0] = tempa[0] ^ Rcon[i/ctx->Nk]; + } +#if defined(AES256) && (AES256 == 1) + if (ctx->KeyLength == 32) { + if (i % ctx->Nk == 4) + { + // Function Subword() + { + tempa[0] = getSBoxValue(tempa[0]); + tempa[1] = getSBoxValue(tempa[1]); + tempa[2] = getSBoxValue(tempa[2]); + tempa[3] = getSBoxValue(tempa[3]); + } + } + } +#endif + j = i * 4; k=(i - ctx->Nk) * 4; + RoundKey[j + 0] = RoundKey[k + 0] ^ tempa[0]; + RoundKey[j + 1] = RoundKey[k + 1] ^ tempa[1]; + RoundKey[j + 2] = RoundKey[k + 2] ^ tempa[2]; + RoundKey[j + 3] = RoundKey[k + 3] ^ tempa[3]; + } +} + +void AES_init_ctx(struct AES_ctx* ctx, const uint8_t* key, uint32_t keylen) +{ + ctx->KeyLength = keylen; + switch (ctx->KeyLength) { +#if defined(AES128) && (AES128 == 1) + case 16: ctx->Nr = Nr128; ctx->Nk = Nk128; break; +#endif +#if defined(AES192) && (AES192 == 1) + case 24: ctx->Nr = Nr192; ctx->Nk = Nk192; break; +#endif +#if defined(AES256) && (AES256 == 1) + case 32: ctx->Nr = Nr256; ctx->Nk = Nk256; break; +#endif + default: ctx->Nr = 0; ctx->Nk = 0; break; + } + KeyExpansion(ctx, key); +} +#if (defined(CBC) && (CBC == 1)) || (defined(CTR) && (CTR == 1)) +void AES_init_ctx_iv(struct AES_ctx* ctx, const uint8_t* key, uint32_t keylen, const uint8_t* iv) +{ + AES_init_ctx(ctx, key, keylen); + memcpy (ctx->Iv, iv, AES_BLOCKLEN); +} +void AES_ctx_set_iv(struct AES_ctx* ctx, const uint8_t* iv) +{ + memcpy (ctx->Iv, iv, AES_BLOCKLEN); +} +#endif + +// This function adds the round key to state. The round key is added to the +// state by an XOR function. +static void AddRoundKey(uint8_t round, state_t* state, const uint8_t* RoundKey) +{ + uint8_t i,j; + for (i = 0; i < 4; ++i) + { + for (j = 0; j < 4; ++j) + { + (*state)[i][j] ^= RoundKey[(round * Nb * 4) + (i * Nb) + j]; + } + } +} + +// The SubBytes Function Substitutes the values in the state matrix with values +// in an S-box. +static void SubBytes(state_t* state) +{ + uint8_t i, j; + for (i = 0; i < 4; ++i) + { + for (j = 0; j < 4; ++j) + { + (*state)[j][i] = getSBoxValue((*state)[j][i]); + } + } +} + +// The ShiftRows() function shifts the rows in the state to the left. Each row +// is shifted with different offset. Offset = Row number. So the first row is +// not shifted. +static void ShiftRows(state_t* state) +{ + uint8_t temp; + + // Rotate first row 1 columns to left + temp = (*state)[0][1]; + (*state)[0][1] = (*state)[1][1]; + (*state)[1][1] = (*state)[2][1]; + (*state)[2][1] = (*state)[3][1]; + (*state)[3][1] = temp; + + // Rotate second row 2 columns to left + temp = (*state)[0][2]; + (*state)[0][2] = (*state)[2][2]; + (*state)[2][2] = temp; + + temp = (*state)[1][2]; + (*state)[1][2] = (*state)[3][2]; + (*state)[3][2] = temp; + + // Rotate third row 3 columns to left + temp = (*state)[0][3]; + (*state)[0][3] = (*state)[3][3]; + (*state)[3][3] = (*state)[2][3]; + (*state)[2][3] = (*state)[1][3]; + (*state)[1][3] = temp; +} + +static uint8_t xtime(uint8_t x) +{ + return ((x<<1) ^ (((x>>7) & 1) * 0x1b)); +} + +// MixColumns function mixes the columns of the state matrix +static void MixColumns(state_t* state) +{ + uint8_t i; + uint8_t Tmp, Tm, t; + for (i = 0; i < 4; ++i) + { + t = (*state)[i][0]; + Tmp = (*state)[i][0] ^ (*state)[i][1] ^ (*state)[i][2] ^ (*state)[i][3] ; + Tm = (*state)[i][0] ^ (*state)[i][1] ; Tm = xtime(Tm); (*state)[i][0] ^= Tm ^ Tmp ; + Tm = (*state)[i][1] ^ (*state)[i][2] ; Tm = xtime(Tm); (*state)[i][1] ^= Tm ^ Tmp ; + Tm = (*state)[i][2] ^ (*state)[i][3] ; Tm = xtime(Tm); (*state)[i][2] ^= Tm ^ Tmp ; + Tm = (*state)[i][3] ^ t ; Tm = xtime(Tm); (*state)[i][3] ^= Tm ^ Tmp ; + } +} + +// Multiply is used to multiply numbers in the field GF(2^8) +// Note: The last call to xtime() is unneeded, but often ends up generating a smaller binary +// The compiler seems to be able to vectorize the operation better this way. +// See https://github.com/kokke/tiny-AES-c/pull/34 +#if MULTIPLY_AS_A_FUNCTION +static uint8_t Multiply(uint8_t x, uint8_t y) +{ + return (((y & 1) * x) ^ + ((y>>1 & 1) * xtime(x)) ^ + ((y>>2 & 1) * xtime(xtime(x))) ^ + ((y>>3 & 1) * xtime(xtime(xtime(x)))) ^ + ((y>>4 & 1) * xtime(xtime(xtime(xtime(x)))))); /* this last call to xtime() can be omitted */ + } +#else +#define Multiply(x, y) \ + ( ((y & 1) * x) ^ \ + ((y>>1 & 1) * xtime(x)) ^ \ + ((y>>2 & 1) * xtime(xtime(x))) ^ \ + ((y>>3 & 1) * xtime(xtime(xtime(x)))) ^ \ + ((y>>4 & 1) * xtime(xtime(xtime(xtime(x)))))) \ + +#endif + +#if (defined(CBC) && CBC == 1) || (defined(ECB) && ECB == 1) +// MixColumns function mixes the columns of the state matrix. The method used to +// multiply may be difficult to understand for the inexperienced. Please use the +// references to gain more information. +static void InvMixColumns(state_t* state) +{ + int i; + uint8_t a, b, c, d; + for (i = 0; i < 4; ++i) + { + a = (*state)[i][0]; + b = (*state)[i][1]; + c = (*state)[i][2]; + d = (*state)[i][3]; + + (*state)[i][0] = Multiply(a, 0x0e) ^ Multiply(b, 0x0b) ^ Multiply(c, 0x0d) ^ Multiply(d, 0x09); + (*state)[i][1] = Multiply(a, 0x09) ^ Multiply(b, 0x0e) ^ Multiply(c, 0x0b) ^ Multiply(d, 0x0d); + (*state)[i][2] = Multiply(a, 0x0d) ^ Multiply(b, 0x09) ^ Multiply(c, 0x0e) ^ Multiply(d, 0x0b); + (*state)[i][3] = Multiply(a, 0x0b) ^ Multiply(b, 0x0d) ^ Multiply(c, 0x09) ^ Multiply(d, 0x0e); + } +} + + +// The SubBytes Function Substitutes the values in the state matrix with values +// in an S-box. +static void InvSubBytes(state_t* state) +{ + uint8_t i, j; + for (i = 0; i < 4; ++i) + { + for (j = 0; j < 4; ++j) + { + (*state)[j][i] = getSBoxInvert((*state)[j][i]); + } + } +} + +static void InvShiftRows(state_t* state) +{ + uint8_t temp; + + // Rotate first row 1 columns to right + temp = (*state)[3][1]; + (*state)[3][1] = (*state)[2][1]; + (*state)[2][1] = (*state)[1][1]; + (*state)[1][1] = (*state)[0][1]; + (*state)[0][1] = temp; + + // Rotate second row 2 columns to right + temp = (*state)[0][2]; + (*state)[0][2] = (*state)[2][2]; + (*state)[2][2] = temp; + + temp = (*state)[1][2]; + (*state)[1][2] = (*state)[3][2]; + (*state)[3][2] = temp; + + // Rotate third row 3 columns to right + temp = (*state)[0][3]; + (*state)[0][3] = (*state)[1][3]; + (*state)[1][3] = (*state)[2][3]; + (*state)[2][3] = (*state)[3][3]; + (*state)[3][3] = temp; +} +#endif // #if (defined(CBC) && CBC == 1) || (defined(ECB) && ECB == 1) + +// Cipher is the main function that encrypts the PlainText. +static void Cipher(state_t* state, const struct AES_ctx* ctx) +{ + const uint8_t* RoundKey = GetRoundKey(ctx); + uint8_t round = 0; + + // Add the First round key to the state before starting the rounds. + AddRoundKey(0, state, RoundKey); + + // There will be Nr rounds. The first Nr-1 rounds are identical. These Nr + // rounds are executed in the loop below. Last one without MixColumns() + for (round = 1; ; ++round) + { + SubBytes(state); + ShiftRows(state); + if (round == ctx->Nr) { + break; + } + MixColumns(state); + AddRoundKey(round, state, RoundKey); + } + // Add round key to last round + AddRoundKey(ctx->Nr, state, RoundKey); +} + +#if (defined(CBC) && CBC == 1) || (defined(ECB) && ECB == 1) +static void InvCipher(state_t* state, const struct AES_ctx* ctx) +{ + const uint8_t* RoundKey = GetRoundKey(ctx); + uint8_t round = 0; + + // Add the First round key to the state before starting the rounds. + AddRoundKey(ctx->Nr, state, RoundKey); + + // There will be Nr rounds. The first Nr-1 rounds are identical. These Nr + // rounds are executed in the loop below. Last one without InvMixColumn() + for (round = (ctx->Nr - 1); ; --round) + { + InvShiftRows(state); + InvSubBytes(state); + AddRoundKey(round, state, RoundKey); + if (round == 0) { + break; + } + InvMixColumns(state); + } + +} +#endif // #if (defined(CBC) && CBC == 1) || (defined(ECB) && ECB == 1) + +/*****************************************************************************/ +/* Public functions: */ +/*****************************************************************************/ +#if defined(ECB) && (ECB == 1) + + +void AES_ECB_encrypt(const struct AES_ctx* ctx, uint8_t* buf) +{ + // The next function call encrypts the PlainText with the Key using AES + // algorithm. + Cipher((state_t*)buf, ctx); +} + +void AES_ECB_decrypt(const struct AES_ctx* ctx, uint8_t* buf) +{ + // The next function call decrypts the PlainText with the Key using AES + // algorithm. + InvCipher((state_t*)buf, ctx); +} + + +#endif // #if defined(ECB) && (ECB == 1) + + + + + +#if defined(CBC) && (CBC == 1) + + +static void XorWithIv(uint8_t* buf, const uint8_t* Iv) +{ + uint8_t i; + for (i = 0; i < AES_BLOCKLEN; ++i) // The block in AES is always 128bit no matter the key size + { + buf[i] ^= Iv[i]; + } +} + +void AES_CBC_encrypt_buffer(struct AES_ctx *ctx, uint8_t* buf, uint32_t length) +{ + uintptr_t i; + uint8_t *Iv = ctx->Iv; + for (i = 0; i < length; i += AES_BLOCKLEN) + { + XorWithIv(buf, Iv); + Cipher((state_t*)buf, ctx); + Iv = buf; + buf += AES_BLOCKLEN; + } + /* store Iv in ctx for next call */ + memcpy(ctx->Iv, Iv, AES_BLOCKLEN); +} + +void AES_CBC_decrypt_buffer(struct AES_ctx* ctx, uint8_t* buf, uint32_t length) +{ + uintptr_t i; + uint8_t storeNextIv[AES_BLOCKLEN]; + for (i = 0; i < length; i += AES_BLOCKLEN) + { + memcpy(storeNextIv, buf, AES_BLOCKLEN); + InvCipher((state_t*)buf, ctx); + XorWithIv(buf, ctx->Iv); + memcpy(ctx->Iv, storeNextIv, AES_BLOCKLEN); + buf += AES_BLOCKLEN; + } + +} + +#endif // #if defined(CBC) && (CBC == 1) + + + +#if defined(CTR) && (CTR == 1) + +/* Symmetrical operation: same function for encrypting as for decrypting. Note +any IV/nonce should never be reused with the same key */ +void AES_CTR_xcrypt_buffer(struct AES_ctx* ctx, uint8_t* buf, uint32_t length) +{ + uint8_t buffer[AES_BLOCKLEN]; + + unsigned i; + int bi; + for (i = 0, bi = AES_BLOCKLEN; i < length; ++i, ++bi) + { + if (bi == AES_BLOCKLEN) /* we need to regen xor compliment in buffer */ + { + memcpy(buffer, ctx->Iv, AES_BLOCKLEN); + Cipher((state_t*)buffer, ctx); + + /* Increment Iv and handle overflow */ + for (bi = (AES_BLOCKLEN - 1); bi >= 0; --bi) + { + /* inc will overflow */ + if (ctx->Iv[bi] == 255) + { + ctx->Iv[bi] = 0; + continue; + } + ctx->Iv[bi] += 1; + break; + } + bi = 0; + } + + buf[i] = (buf[i] ^ buffer[bi]); + } +} + +#endif // #if defined(CTR) && (CTR == 1) diff --git a/shared-module/aesio/aes.h b/shared-module/aesio/aes.h new file mode 100644 index 0000000000..a87fa5be75 --- /dev/null +++ b/shared-module/aesio/aes.h @@ -0,0 +1,105 @@ +#ifndef _AES_H_ +#define _AES_H_ + +#include + +// #define the macros below to 1/0 to enable/disable the mode of operation. +// +// CBC enables AES encryption in CBC-mode of operation. +// CTR enables encryption in counter-mode. +// ECB enables the basic ECB 16-byte block algorithm. All can be enabled simultaneously. + +// The #ifndef-guard allows it to be configured before #include'ing or at compile time. +#ifndef CBC + #define CBC 1 +#endif + +#ifndef ECB + #define ECB 1 +#endif + +#ifndef CTR + #define CTR 1 +#endif + + +#define AES128 1 +#define AES192 1 +#define AES256 1 + +#define AES_BLOCKLEN 16 // Block length in bytes - AES is 128b block only + +#if defined(AES256) && (AES256 == 1) + #define AES_KEYLEN256 32 + #define AES_keyExpSize256 240 +#endif +#if defined(AES192) && (AES192 == 1) + #define AES_KEYLEN192 24 + #define AES_keyExpSize192 208 +#endif +#if defined(AES128) && (AES128 == 1) + #define AES_KEYLEN128 16 // Key length in bytes + #define AES_keyExpSize128 176 +#endif + +struct AES_ctx +{ + union { +#if defined(AES256) && (AES256 == 1) + uint8_t RoundKey256[AES_keyExpSize256]; +#endif +#if defined(AES192) && (AES192 == 1) + uint8_t RoundKey192[AES_keyExpSize192]; +#endif +#if defined(AES128) && (AES128 == 1) + uint8_t RoundKey128[AES_keyExpSize128]; +#endif + }; +#if (defined(CBC) && (CBC == 1)) || (defined(CTR) && (CTR == 1)) + uint8_t Iv[AES_BLOCKLEN]; +#endif + uint32_t KeyLength; + uint8_t Nr; + uint8_t Nk; +}; + +void AES_init_ctx(struct AES_ctx* ctx, const uint8_t* key, uint32_t keylen); +#if (defined(CBC) && (CBC == 1)) || (defined(CTR) && (CTR == 1)) +void AES_init_ctx_iv(struct AES_ctx* ctx, const uint8_t* key, uint32_t keylen, const uint8_t* iv); +void AES_ctx_set_iv(struct AES_ctx* ctx, const uint8_t* iv); +#endif + +#if defined(ECB) && (ECB == 1) +// buffer size is exactly AES_BLOCKLEN bytes; +// you need only AES_init_ctx as IV is not used in ECB +// NB: ECB is considered insecure for most uses +void AES_ECB_encrypt(const struct AES_ctx* ctx, uint8_t* buf); +void AES_ECB_decrypt(const struct AES_ctx* ctx, uint8_t* buf); + +#endif // #if defined(ECB) && (ECB == !) + + +#if defined(CBC) && (CBC == 1) +// buffer size MUST be mutile of AES_BLOCKLEN; +// Suggest https://en.wikipedia.org/wiki/Padding_(cryptography)#PKCS7 for padding scheme +// NOTES: you need to set IV in ctx via AES_init_ctx_iv() or AES_ctx_set_iv() +// no IV should ever be reused with the same key +void AES_CBC_encrypt_buffer(struct AES_ctx* ctx, uint8_t* buf, uint32_t length); +void AES_CBC_decrypt_buffer(struct AES_ctx* ctx, uint8_t* buf, uint32_t length); + +#endif // #if defined(CBC) && (CBC == 1) + + +#if defined(CTR) && (CTR == 1) + +// Same function for encrypting as for decrypting. +// IV is incremented for every block, and used after encryption as XOR-compliment for output +// Suggesting https://en.wikipedia.org/wiki/Padding_(cryptography)#PKCS7 for padding scheme +// NOTES: you need to set IV in ctx with AES_init_ctx_iv() or AES_ctx_set_iv() +// no IV should ever be reused with the same key +void AES_CTR_xcrypt_buffer(struct AES_ctx* ctx, uint8_t* buf, uint32_t length); + +#endif // #if defined(CTR) && (CTR == 1) + + +#endif // _AES_H_