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trezor-firmware/chacha20poly1305/ecrypt-sync.h
2017-05-11 13:27:59 +02:00

282 lines
7.4 KiB
C

#define ECRYPT_VARIANT 1
#define ECRYPT_API
/* ecrypt-sync.h */
/*
* Header file for synchronous stream ciphers without authentication
* mechanism.
*
* *** Please only edit parts marked with "[edit]". ***
*/
#ifndef ECRYPT_SYNC
#define ECRYPT_SYNC
#include "ecrypt-portable.h"
/* ------------------------------------------------------------------------- */
/* Cipher parameters */
/*
* The name of your cipher.
*/
#define ECRYPT_NAME "ChaCha20"
#define ECRYPT_PROFILE "_____"
/*
* Specify which key and IV sizes are supported by your cipher. A user
* should be able to enumerate the supported sizes by running the
* following code:
*
* for (i = 0; ECRYPT_KEYSIZE(i) <= ECRYPT_MAXKEYSIZE; ++i)
* {
* keysize = ECRYPT_KEYSIZE(i);
*
* ...
* }
*
* All sizes are in bits.
*/
#define ECRYPT_MAXKEYSIZE 256 /* [edit] */
#define ECRYPT_KEYSIZE(i) (128 + (i)*128) /* [edit] */
#define ECRYPT_MAXIVSIZE 64 /* [edit] */
#define ECRYPT_IVSIZE(i) (64 + (i)*64) /* [edit] */
/* ------------------------------------------------------------------------- */
/* Data structures */
/*
* ECRYPT_ctx is the structure containing the representation of the
* internal state of your cipher.
*/
typedef struct
{
u32 input[16]; /* could be compressed */
/*
* [edit]
*
* Put here all state variable needed during the encryption process.
*/
} ECRYPT_ctx;
/* ------------------------------------------------------------------------- */
/* Mandatory functions */
/*
* Key and message independent initialization. This function will be
* called once when the program starts (e.g., to build expanded S-box
* tables).
*/
void ECRYPT_init(void);
/*
* Key setup. It is the user's responsibility to select the values of
* keysize and ivsize from the set of supported values specified
* above.
*/
void ECRYPT_keysetup(
ECRYPT_ctx* ctx,
const u8* key,
u32 keysize, /* Key size in bits. */
u32 ivsize); /* IV size in bits. */
/*
* IV setup. After having called ECRYPT_keysetup(), the user is
* allowed to call ECRYPT_ivsetup() different times in order to
* encrypt/decrypt different messages with the same key but different
* IV's.
*/
void ECRYPT_ivsetup(
ECRYPT_ctx* ctx,
const u8* iv);
/*
* Encryption/decryption of arbitrary length messages.
*
* For efficiency reasons, the API provides two types of
* encrypt/decrypt functions. The ECRYPT_encrypt_bytes() function
* (declared here) encrypts byte strings of arbitrary length, while
* the ECRYPT_encrypt_blocks() function (defined later) only accepts
* lengths which are multiples of ECRYPT_BLOCKLENGTH.
*
* The user is allowed to make multiple calls to
* ECRYPT_encrypt_blocks() to incrementally encrypt a long message,
* but he is NOT allowed to make additional encryption calls once he
* has called ECRYPT_encrypt_bytes() (unless he starts a new message
* of course). For example, this sequence of calls is acceptable:
*
* ECRYPT_keysetup();
*
* ECRYPT_ivsetup();
* ECRYPT_encrypt_blocks();
* ECRYPT_encrypt_blocks();
* ECRYPT_encrypt_bytes();
*
* ECRYPT_ivsetup();
* ECRYPT_encrypt_blocks();
* ECRYPT_encrypt_blocks();
*
* ECRYPT_ivsetup();
* ECRYPT_encrypt_bytes();
*
* The following sequence is not:
*
* ECRYPT_keysetup();
* ECRYPT_ivsetup();
* ECRYPT_encrypt_blocks();
* ECRYPT_encrypt_bytes();
* ECRYPT_encrypt_blocks();
*/
void ECRYPT_encrypt_bytes(
ECRYPT_ctx* ctx,
const u8* plaintext,
u8* ciphertext,
u32 msglen); /* Message length in bytes. */
void ECRYPT_decrypt_bytes(
ECRYPT_ctx* ctx,
const u8* ciphertext,
u8* plaintext,
u32 msglen); /* Message length in bytes. */
/* ------------------------------------------------------------------------- */
/* Optional features */
/*
* For testing purposes it can sometimes be useful to have a function
* which immediately generates keystream without having to provide it
* with a zero plaintext. If your cipher cannot provide this function
* (e.g., because it is not strictly a synchronous cipher), please
* reset the ECRYPT_GENERATES_KEYSTREAM flag.
*/
#define ECRYPT_GENERATES_KEYSTREAM
#ifdef ECRYPT_GENERATES_KEYSTREAM
void ECRYPT_keystream_bytes(
ECRYPT_ctx* ctx,
u8* keystream,
u32 length); /* Length of keystream in bytes. */
#endif
/* ------------------------------------------------------------------------- */
/* Optional optimizations */
/*
* By default, the functions in this section are implemented using
* calls to functions declared above. However, you might want to
* implement them differently for performance reasons.
*/
/*
* All-in-one encryption/decryption of (short) packets.
*
* The default definitions of these functions can be found in
* "ecrypt-sync.c". If you want to implement them differently, please
* undef the ECRYPT_USES_DEFAULT_ALL_IN_ONE flag.
*/
#define ECRYPT_USES_DEFAULT_ALL_IN_ONE /* [edit] */
void ECRYPT_encrypt_packet(
ECRYPT_ctx* ctx,
const u8* iv,
const u8* plaintext,
u8* ciphertext,
u32 msglen);
void ECRYPT_decrypt_packet(
ECRYPT_ctx* ctx,
const u8* iv,
const u8* ciphertext,
u8* plaintext,
u32 msglen);
/*
* Encryption/decryption of blocks.
*
* By default, these functions are defined as macros. If you want to
* provide a different implementation, please undef the
* ECRYPT_USES_DEFAULT_BLOCK_MACROS flag and implement the functions
* declared below.
*/
#define ECRYPT_BLOCKLENGTH 64 /* [edit] */
#define ECRYPT_USES_DEFAULT_BLOCK_MACROS /* [edit] */
#ifdef ECRYPT_USES_DEFAULT_BLOCK_MACROS
#define ECRYPT_encrypt_blocks(ctx, plaintext, ciphertext, blocks) \
ECRYPT_encrypt_bytes(ctx, plaintext, ciphertext, \
(blocks) * ECRYPT_BLOCKLENGTH)
#define ECRYPT_decrypt_blocks(ctx, ciphertext, plaintext, blocks) \
ECRYPT_decrypt_bytes(ctx, ciphertext, plaintext, \
(blocks) * ECRYPT_BLOCKLENGTH)
#ifdef ECRYPT_GENERATES_KEYSTREAM
#define ECRYPT_keystream_blocks(ctx, keystream, blocks) \
ECRYPT_keystream_bytes(ctx, keystream, \
(blocks) * ECRYPT_BLOCKLENGTH)
#endif
#else
void ECRYPT_encrypt_blocks(
ECRYPT_ctx* ctx,
const u8* plaintext,
u8* ciphertext,
u32 blocks); /* Message length in blocks. */
void ECRYPT_decrypt_blocks(
ECRYPT_ctx* ctx,
const u8* ciphertext,
u8* plaintext,
u32 blocks); /* Message length in blocks. */
#ifdef ECRYPT_GENERATES_KEYSTREAM
void ECRYPT_keystream_blocks(
ECRYPT_ctx* ctx,
const u8* keystream,
u32 blocks); /* Keystream length in blocks. */
#endif
#endif
/*
* If your cipher can be implemented in different ways, you can use
* the ECRYPT_VARIANT parameter to allow the user to choose between
* them at compile time (e.g., gcc -DECRYPT_VARIANT=3 ...). Please
* only use this possibility if you really think it could make a
* significant difference and keep the number of variants
* (ECRYPT_MAXVARIANT) as small as possible (definitely not more than
* 10). Note also that all variants should have exactly the same
* external interface (i.e., the same ECRYPT_BLOCKLENGTH, etc.).
*/
#define ECRYPT_MAXVARIANT 1 /* [edit] */
#ifndef ECRYPT_VARIANT
#define ECRYPT_VARIANT 1
#endif
#if (ECRYPT_VARIANT > ECRYPT_MAXVARIANT)
#error this variant does not exist
#endif
/* ------------------------------------------------------------------------- */
#endif