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/**************************************************************************/
/* */
/* Copyright (c) Microsoft Corporation. All rights reserved. */
/* */
/* This software is licensed under the Microsoft Software License */
/* Terms for Microsoft Azure RTOS. Full text of the license can be */
/* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
/* and in the root directory of this software. */
/* */
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** NetX Crypto Component */
/** */
/** CTR Mode */
/** */
/**************************************************************************/
/**************************************************************************/
#include "nx_crypto_ctr.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_crypto_ctr_xor PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function performs XOR operation on the output buffer. */
/* */
/* INPUT */
/* */
/* plaintext Pointer to input plantext */
/* key Value to be xor'ed */
/* ciphertext Output buffer of 16 bytes */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* None */
/* */
/* CALLED BY */
/* */
/* _nx_crypto_ctr_encrypt Perform CTR mode encryption */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), disabled */
/* unaligned access by default,*/
/* resulting in version 6.1 */
/* */
/**************************************************************************/
NX_CRYPTO_KEEP static VOID _nx_crypto_ctr_xor(UCHAR *plaintext, UCHAR *key, UCHAR *ciphertext)
{
#ifdef NX_CRYPTO_ENABLE_UNALIGNED_ACCESS
UINT *p = (UINT *)plaintext;
UINT *c = (UINT *)ciphertext;
UINT *k = (UINT *)key;
c[0] = p[0] ^ k[0];
c[1] = p[1] ^ k[1];
c[2] = p[2] ^ k[2];
c[3] = p[3] ^ k[3];
#else
ciphertext[0] = plaintext[0] ^ key[0];
ciphertext[1] = plaintext[1] ^ key[1];
ciphertext[2] = plaintext[2] ^ key[2];
ciphertext[3] = plaintext[3] ^ key[3];
ciphertext[4] = plaintext[4] ^ key[4];
ciphertext[5] = plaintext[5] ^ key[5];
ciphertext[6] = plaintext[6] ^ key[6];
ciphertext[7] = plaintext[7] ^ key[7];
ciphertext[8] = plaintext[8] ^ key[8];
ciphertext[9] = plaintext[9] ^ key[9];
ciphertext[10] = plaintext[10] ^ key[10];
ciphertext[11] = plaintext[11] ^ key[11];
ciphertext[12] = plaintext[12] ^ key[12];
ciphertext[13] = plaintext[13] ^ key[13];
ciphertext[14] = plaintext[14] ^ key[14];
ciphertext[15] = plaintext[15] ^ key[15];
#endif
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_crypto_ctr_add_one PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function adds one for the last byte. */
/* */
/* INPUT */
/* */
/* control_block Pointer to control block */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* None */
/* */
/* CALLED BY */
/* */
/* _nx_crypto_ctr_encrypt Perform CTR mode encryption */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
NX_CRYPTO_KEEP static VOID _nx_crypto_ctr_add_one(UCHAR *control_block)
{
USHORT result;
/* Add one for last byte. */
result = (USHORT)(control_block[15] + 1);
control_block[15] = (UCHAR)(result & 0xFF);
/* Handle carry. */
result = (USHORT)((result >> 8) + control_block[14]);
control_block[14] = (UCHAR)(result & 0xFF);
result = (USHORT)((result >> 8) + control_block[13]);
control_block[13] = (UCHAR)(result & 0xFF);
result = (USHORT)((result >> 8) + control_block[12]);
control_block[12] = (UCHAR)(result & 0xFF);
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_crypto_ctr_encrypt PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function performs CTR mode encryption, only support block of */
/* 16 bytes. */
/* */
/* INPUT */
/* */
/* crypto_metadata Pointer to crypto metadata */
/* ctr_metadata Pointer to CTR metadata */
/* crypto_function Pointer to crypto function */
/* key_set_function Pointer to key set function */
/* additional_data Pointer to the additional data*/
/* additional_len Length of additional data */
/* input Pointer to clear text input */
/* output Pointer to encrypted output */
/* The size of the output */
/* buffer must be at least */
/* the size of input message. */
/* length Length of the input message. */
/* iv Nonce length + Nonce */
/* icv_len ICV length */
/* block_size Block size */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_crypto_ctr_xor Perform XOR operation */
/* _nx_crypto_ctr_add_one Perform add one operation */
/* */
/* CALLED BY */
/* */
/* _nx_crypto_method_aes_ctr_operation Handle AES encrypt or decrypt */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* verified memcpy use cases, */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
NX_CRYPTO_KEEP UINT _nx_crypto_ctr_encrypt(VOID *crypto_metadata, NX_CRYPTO_CTR *ctr_metadata,
UINT (*crypto_function)(VOID *, UCHAR *, UCHAR *, UINT),
UCHAR *input, UCHAR *output, UINT length, UINT block_size)
{
UCHAR *control_block = ctr_metadata -> nx_crypto_ctr_counter_block;
UCHAR aes_output[NX_CRYPTO_CTR_BLOCK_SIZE];
UINT i;
/* Check the block size. */
if (block_size != NX_CRYPTO_CTR_BLOCK_SIZE)
{
return(NX_CRYPTO_PTR_ERROR);
}
for (i = 0; i < length; i += block_size)
{
if (length - i < block_size)
{
break;
}
crypto_function(crypto_metadata, control_block, aes_output, block_size);
_nx_crypto_ctr_xor(&input[i], aes_output, &output[i]);
_nx_crypto_ctr_add_one(control_block);
}
/* If the input is not an even multiple of 16 bytes, we need to truncate and xor the remainder. */
if (length - i != 0)
{
crypto_function(crypto_metadata, control_block, aes_output, block_size);
_nx_crypto_ctr_xor(&input[i], aes_output, aes_output);
NX_CRYPTO_MEMCPY(&output[i], aes_output, length - i); /* Use case of memcpy is verified. */
}
#ifdef NX_SECURE_KEY_CLEAR
NX_CRYPTO_MEMSET(aes_output, 0, sizeof(aes_output));
#endif /* NX_SECURE_KEY_CLEAR */
return(NX_CRYPTO_SUCCESS);
}
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_crypto_ctr_encrypt_init PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function performs CTR mode initialization. */
/* */
/* INPUT */
/* */
/* ctr_metadata Pointer to CTR metadata */
/* iv Pointer to Initial Vector */
/* iv_len Length of IV. Must be 8 */
/* nonce Pointer to Nonce */
/* nonce_len Length of Nonce. Must be 4 */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* None */
/* */
/* CALLED BY */
/* */
/* _nx_crypto_method_aes_ctr_operation Handle AES encrypt or decrypt */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* verified memcpy use cases, */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
NX_CRYPTO_KEEP UINT _nx_crypto_ctr_encrypt_init(NX_CRYPTO_CTR *ctr_metadata, UCHAR *iv, UINT iv_len,
UCHAR *nonce, UINT nonce_len)
{
UCHAR *control_block = ctr_metadata -> nx_crypto_ctr_counter_block;
/* Check IV length and Nonce length. */
if ((iv_len != 8) || (nonce_len != 4))
{
return(NX_CRYPTO_PTR_ERROR);
}
/* Control block consists of the following data:
* Bits: | 0-31 (32 bits) | 32-95 (64 bits) | 96-127 (32 bits) |
* | All set to 1 | Initialization Vector (IV) | Nonce |
*/
NX_CRYPTO_MEMSET(control_block, 0x0, 16);
control_block[15] = 1;
NX_CRYPTO_MEMCPY(&control_block[4], iv, 8); /* Use case of memcpy is verified. */
NX_CRYPTO_MEMCPY(&control_block[0], nonce, 4); /* Use case of memcpy is verified. */
return(NX_CRYPTO_SUCCESS);
}