crypto/modes/siv128.c - third_party/openssl - Git at Google

 /*
  * Copyright 2018-2021 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the Apache License 2.0 (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
  * in the file LICENSE in the source distribution or at
  * https://www.openssl.org/source/license.html
  */

 #include <string.h>
 #include <stdlib.h>
 #include <openssl/crypto.h>
 #include <openssl/evp.h>
 #include <openssl/core_names.h>
 #include <openssl/params.h>
 #include "internal/endian.h"
 #include "crypto/modes.h"
 #include "crypto/siv.h"

 #ifndef OPENSSL_NO_SIV

 __owur static ossl_inline uint32_t rotl8(uint32_t x)
 {
     return (x << 8) | (x >> 24);
 }

 __owur static ossl_inline uint32_t rotr8(uint32_t x)
 {
     return (x >> 8) | (x << 24);
 }

 __owur static ossl_inline uint64_t byteswap8(uint64_t x)
 {
     uint32_t high = (uint32_t)(x >> 32);
     uint32_t low = (uint32_t)x;

     high = (rotl8(high) & 0x00ff00ff) | (rotr8(high) & 0xff00ff00);
     low = (rotl8(low) & 0x00ff00ff) | (rotr8(low) & 0xff00ff00);
     return ((uint64_t)low) << 32 | (uint64_t)high;
 }

 __owur static ossl_inline uint64_t siv128_getword(SIV_BLOCK const *b, size_t i)
 {
     DECLARE_IS_ENDIAN;

     if (IS_LITTLE_ENDIAN)
         return byteswap8(b->word[i]);
     return b->word[i];
 }

 static ossl_inline void siv128_putword(SIV_BLOCK *b, size_t i, uint64_t x)
 {
     DECLARE_IS_ENDIAN;

     if (IS_LITTLE_ENDIAN)
         b->word[i] = byteswap8(x);
     else
         b->word[i] = x;
 }

 static ossl_inline void siv128_xorblock(SIV_BLOCK *x,
                                         SIV_BLOCK const *y)
 {
     x->word[0] ^= y->word[0];
     x->word[1] ^= y->word[1];
 }

 /*
  * Doubles |b|, which is 16 bytes representing an element
  * of GF(2**128) modulo the irreducible polynomial
  * x**128 + x**7 + x**2 + x + 1.
  * Assumes two's-complement arithmetic
  */
 static ossl_inline void siv128_dbl(SIV_BLOCK *b)
 {
     uint64_t high = siv128_getword(b, 0);
     uint64_t low = siv128_getword(b, 1);
     uint64_t high_carry = high & (((uint64_t)1) << 63);
     uint64_t low_carry = low & (((uint64_t)1) << 63);
     int64_t low_mask = -((int64_t)(high_carry >> 63)) & 0x87;
     uint64_t high_mask = low_carry >> 63;

     high = (high << 1) | high_mask;
     low = (low << 1) ^ (uint64_t)low_mask;
     siv128_putword(b, 0, high);
     siv128_putword(b, 1, low);
 }

 __owur static ossl_inline int siv128_do_s2v_p(SIV128_CONTEXT *ctx, SIV_BLOCK *out,
                                               unsigned char const* in, size_t len)
 {
     SIV_BLOCK t;
     size_t out_len = sizeof(out->byte);
     EVP_MAC_CTX *mac_ctx;
     int ret = 0;

     mac_ctx = EVP_MAC_CTX_dup(ctx->mac_ctx_init);
     if (mac_ctx == NULL)
         return 0;

     if (len >= SIV_LEN) {
         if (!EVP_MAC_update(mac_ctx, in, len - SIV_LEN))
             goto err;
         memcpy(&t, in + (len-SIV_LEN), SIV_LEN);
         siv128_xorblock(&t, &ctx->d);
         if (!EVP_MAC_update(mac_ctx, t.byte, SIV_LEN))
             goto err;
     } else {
         memset(&t, 0, sizeof(t));
         memcpy(&t, in, len);
         t.byte[len] = 0x80;
         siv128_dbl(&ctx->d);
         siv128_xorblock(&t, &ctx->d);
         if (!EVP_MAC_update(mac_ctx, t.byte, SIV_LEN))
             goto err;
     }
     if (!EVP_MAC_final(mac_ctx, out->byte, &out_len, sizeof(out->byte))
         || out_len != SIV_LEN)
         goto err;

     ret = 1;

 err:
     EVP_MAC_CTX_free(mac_ctx);
     return ret;
 }


 __owur static ossl_inline int siv128_do_encrypt(EVP_CIPHER_CTX *ctx, unsigned char *out,
                                              unsigned char const *in, size_t len,
                                              SIV_BLOCK *icv)
 {
     int out_len = (int)len;

     if (!EVP_CipherInit_ex(ctx, NULL, NULL, NULL, icv->byte, 1))
         return 0;
     return EVP_EncryptUpdate(ctx, out, &out_len, in, out_len);
 }

 /*
  * Create a new SIV128_CONTEXT
  */
 SIV128_CONTEXT *ossl_siv128_new(const unsigned char *key, int klen,
                                   EVP_CIPHER *cbc, EVP_CIPHER *ctr,
                                   OSSL_LIB_CTX *libctx, const char *propq)
 {
     SIV128_CONTEXT *ctx;
     int ret;

     if ((ctx = OPENSSL_malloc(sizeof(*ctx))) != NULL) {
         ret = ossl_siv128_init(ctx, key, klen, cbc, ctr, libctx, propq);
         if (ret)
             return ctx;
         OPENSSL_free(ctx);
     }

     return NULL;
 }

 /*
  * Initialise an existing SIV128_CONTEXT
  */
 int ossl_siv128_init(SIV128_CONTEXT *ctx, const unsigned char *key, int klen,
                        const EVP_CIPHER *cbc, const EVP_CIPHER *ctr,
                        OSSL_LIB_CTX *libctx, const char *propq)
 {
     static const unsigned char zero[SIV_LEN] = { 0 };
     size_t out_len = SIV_LEN;
     EVP_MAC_CTX *mac_ctx = NULL;
     OSSL_PARAM params[3];
     const char *cbc_name;

     if (ctx == NULL)
         return 0;

     memset(&ctx->d, 0, sizeof(ctx->d));
     EVP_CIPHER_CTX_free(ctx->cipher_ctx);
     EVP_MAC_CTX_free(ctx->mac_ctx_init);
     EVP_MAC_free(ctx->mac);
     ctx->mac = NULL;
     ctx->cipher_ctx = NULL;
     ctx->mac_ctx_init = NULL;

     if (key == NULL || cbc == NULL || ctr == NULL)
         return 0;

     cbc_name = EVP_CIPHER_name(cbc);
     params[0] = OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_CIPHER,
                                                  (char *)cbc_name, 0);
     params[1] = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
                                                   (void *)key, klen);
     params[2] = OSSL_PARAM_construct_end();

     if ((ctx->cipher_ctx = EVP_CIPHER_CTX_new()) == NULL
             || (ctx->mac =
                 EVP_MAC_fetch(libctx, OSSL_MAC_NAME_CMAC, propq)) == NULL
             || (ctx->mac_ctx_init = EVP_MAC_CTX_new(ctx->mac)) == NULL
             || !EVP_MAC_CTX_set_params(ctx->mac_ctx_init, params)
             || !EVP_EncryptInit_ex(ctx->cipher_ctx, ctr, NULL, key + klen, NULL)
             || (mac_ctx = EVP_MAC_CTX_dup(ctx->mac_ctx_init)) == NULL
             || !EVP_MAC_update(mac_ctx, zero, sizeof(zero))
             || !EVP_MAC_final(mac_ctx, ctx->d.byte, &out_len,
                               sizeof(ctx->d.byte))) {
         EVP_CIPHER_CTX_free(ctx->cipher_ctx);
         EVP_MAC_CTX_free(ctx->mac_ctx_init);
         EVP_MAC_CTX_free(mac_ctx);
         EVP_MAC_free(ctx->mac);
         return 0;
     }
     EVP_MAC_CTX_free(mac_ctx);

     ctx->final_ret = -1;
     ctx->crypto_ok = 1;

     return 1;
 }

 /*
  * Copy an SIV128_CONTEXT object
  */
 int ossl_siv128_copy_ctx(SIV128_CONTEXT *dest, SIV128_CONTEXT *src)
 {
     memcpy(&dest->d, &src->d, sizeof(src->d));
     if (dest->cipher_ctx == NULL) {
         dest->cipher_ctx = EVP_CIPHER_CTX_new();
         if (dest->cipher_ctx == NULL)
             return 0;
     }
     if (!EVP_CIPHER_CTX_copy(dest->cipher_ctx, src->cipher_ctx))
         return 0;
     EVP_MAC_CTX_free(dest->mac_ctx_init);
     dest->mac_ctx_init = EVP_MAC_CTX_dup(src->mac_ctx_init);
     if (dest->mac_ctx_init == NULL)
         return 0;
     dest->mac = src->mac;
     if (dest->mac != NULL)
         EVP_MAC_up_ref(dest->mac);
     return 1;
 }

 /*
  * Provide any AAD. This can be called multiple times.
  * Per RFC5297, the last piece of associated data
  * is the nonce, but it's not treated special
  */
 int ossl_siv128_aad(SIV128_CONTEXT *ctx, const unsigned char *aad,
                       size_t len)
 {
     SIV_BLOCK mac_out;
     size_t out_len = SIV_LEN;
     EVP_MAC_CTX *mac_ctx;

     siv128_dbl(&ctx->d);

     if ((mac_ctx = EVP_MAC_CTX_dup(ctx->mac_ctx_init)) == NULL
         || !EVP_MAC_update(mac_ctx, aad, len)
         || !EVP_MAC_final(mac_ctx, mac_out.byte, &out_len,
                           sizeof(mac_out.byte))
         || out_len != SIV_LEN) {
         EVP_MAC_CTX_free(mac_ctx);
         return 0;
     }
     EVP_MAC_CTX_free(mac_ctx);

     siv128_xorblock(&ctx->d, &mac_out);

     return 1;
 }

 /*
  * Provide any data to be encrypted. This can be called once.
  */
 int ossl_siv128_encrypt(SIV128_CONTEXT *ctx,
                           const unsigned char *in, unsigned char *out,
                           size_t len)
 {
     SIV_BLOCK q;

     /* can only do one crypto operation */
     if (ctx->crypto_ok == 0)
         return 0;
     ctx->crypto_ok--;

     if (!siv128_do_s2v_p(ctx, &q, in, len))
         return 0;

     memcpy(ctx->tag.byte, &q, SIV_LEN);
     q.byte[8] &= 0x7f;
     q.byte[12] &= 0x7f;

     if (!siv128_do_encrypt(ctx->cipher_ctx, out, in, len, &q))
         return 0;
     ctx->final_ret = 0;
     return len;
 }

 /*
  * Provide any data to be decrypted. This can be called once.
  */
 int ossl_siv128_decrypt(SIV128_CONTEXT *ctx,
                           const unsigned char *in, unsigned char *out,
                           size_t len)
 {
     unsigned char* p;
     SIV_BLOCK t, q;
     int i;

     /* can only do one crypto operation */
     if (ctx->crypto_ok == 0)
         return 0;
     ctx->crypto_ok--;

     memcpy(&q, ctx->tag.byte, SIV_LEN);
     q.byte[8] &= 0x7f;
     q.byte[12] &= 0x7f;

     if (!siv128_do_encrypt(ctx->cipher_ctx, out, in, len, &q)
         || !siv128_do_s2v_p(ctx, &t, out, len))
         return 0;

     p = ctx->tag.byte;
     for (i = 0; i < SIV_LEN; i++)
         t.byte[i] ^= p[i];

     if ((t.word[0] | t.word[1]) != 0) {
         OPENSSL_cleanse(out, len);
         return 0;
     }
     ctx->final_ret = 0;
     return len;
 }

 /*
  * Return the already calculated final result.
  */
 int ossl_siv128_finish(SIV128_CONTEXT *ctx)
 {
     return ctx->final_ret;
 }

 /*
  * Set the tag
  */
 int ossl_siv128_set_tag(SIV128_CONTEXT *ctx, const unsigned char *tag, size_t len)
 {
     if (len != SIV_LEN)
         return 0;

     /* Copy the tag from the supplied buffer */
     memcpy(ctx->tag.byte, tag, len);
     return 1;
 }

 /*
  * Retrieve the calculated tag
  */
 int ossl_siv128_get_tag(SIV128_CONTEXT *ctx, unsigned char *tag, size_t len)
 {
     if (len != SIV_LEN)
         return 0;

     /* Copy the tag into the supplied buffer */
     memcpy(tag, ctx->tag.byte, len);
     return 1;
 }

 /*
  * Release all resources
  */
 int ossl_siv128_cleanup(SIV128_CONTEXT *ctx)
 {
     if (ctx != NULL) {
         EVP_CIPHER_CTX_free(ctx->cipher_ctx);
         ctx->cipher_ctx = NULL;
         EVP_MAC_CTX_free(ctx->mac_ctx_init);
         ctx->mac_ctx_init = NULL;
         EVP_MAC_free(ctx->mac);
         ctx->mac = NULL;
         OPENSSL_cleanse(&ctx->d, sizeof(ctx->d));
         OPENSSL_cleanse(&ctx->tag, sizeof(ctx->tag));
         ctx->final_ret = -1;
         ctx->crypto_ok = 1;
     }
     return 1;
 }

 int ossl_siv128_speed(SIV128_CONTEXT *ctx, int arg)
 {
     ctx->crypto_ok = (arg == 1) ? -1 : 1;
     return 1;
 }

 #endif                          /* OPENSSL_NO_SIV */
	/*
	* Copyright 2018-2021 The OpenSSL Project Authors. All Rights Reserved.
	*
	* Licensed under the Apache License 2.0 (the "License"). You may not use
	* this file except in compliance with the License. You can obtain a copy
	* in the file LICENSE in the source distribution or at
	* https://www.openssl.org/source/license.html
	*/

	#include <string.h>
	#include <stdlib.h>
	#include <openssl/crypto.h>
	#include <openssl/evp.h>
	#include <openssl/core_names.h>
	#include <openssl/params.h>
	#include "internal/endian.h"
	#include "crypto/modes.h"
	#include "crypto/siv.h"

	#ifndef OPENSSL_NO_SIV

	__owur static ossl_inline uint32_t rotl8(uint32_t x)
	{
	return (x << 8) \| (x >> 24);
	}

	__owur static ossl_inline uint32_t rotr8(uint32_t x)
	{
	return (x >> 8) \| (x << 24);
	}

	__owur static ossl_inline uint64_t byteswap8(uint64_t x)
	{
	uint32_t high = (uint32_t)(x >> 32);
	uint32_t low = (uint32_t)x;

	high = (rotl8(high) & 0x00ff00ff) \| (rotr8(high) & 0xff00ff00);
	low = (rotl8(low) & 0x00ff00ff) \| (rotr8(low) & 0xff00ff00);
	return ((uint64_t)low) << 32 \| (uint64_t)high;
	}

	__owur static ossl_inline uint64_t siv128_getword(SIV_BLOCK const *b, size_t i)
	{
	DECLARE_IS_ENDIAN;

	if (IS_LITTLE_ENDIAN)
	return byteswap8(b->word[i]);
	return b->word[i];
	}

	static ossl_inline void siv128_putword(SIV_BLOCK *b, size_t i, uint64_t x)
	{
	DECLARE_IS_ENDIAN;

	if (IS_LITTLE_ENDIAN)
	b->word[i] = byteswap8(x);
	else
	b->word[i] = x;
	}

	static ossl_inline void siv128_xorblock(SIV_BLOCK *x,
	SIV_BLOCK const *y)
	{
	x->word[0] ^= y->word[0];
	x->word[1] ^= y->word[1];
	}

	/*
	* Doubles \|b\|, which is 16 bytes representing an element
	* of GF(2**128) modulo the irreducible polynomial
	* x128 + x7 + x**2 + x + 1.
	* Assumes two's-complement arithmetic
	*/
	static ossl_inline void siv128_dbl(SIV_BLOCK *b)
	{
	uint64_t high = siv128_getword(b, 0);
	uint64_t low = siv128_getword(b, 1);
	uint64_t high_carry = high & (((uint64_t)1) << 63);
	uint64_t low_carry = low & (((uint64_t)1) << 63);
	int64_t low_mask = -((int64_t)(high_carry >> 63)) & 0x87;
	uint64_t high_mask = low_carry >> 63;

	high = (high << 1) \| high_mask;
	low = (low << 1) ^ (uint64_t)low_mask;
	siv128_putword(b, 0, high);
	siv128_putword(b, 1, low);
	}

	__owur static ossl_inline int siv128_do_s2v_p(SIV128_CONTEXT ctx, SIV_BLOCK out,
	unsigned char const* in, size_t len)
	{
	SIV_BLOCK t;
	size_t out_len = sizeof(out->byte);
	EVP_MAC_CTX *mac_ctx;
	int ret = 0;

	mac_ctx = EVP_MAC_CTX_dup(ctx->mac_ctx_init);
	if (mac_ctx == NULL)
	return 0;

	if (len >= SIV_LEN) {
	if (!EVP_MAC_update(mac_ctx, in, len - SIV_LEN))
	goto err;
	memcpy(&t, in + (len-SIV_LEN), SIV_LEN);
	siv128_xorblock(&t, &ctx->d);
	if (!EVP_MAC_update(mac_ctx, t.byte, SIV_LEN))
	goto err;
	} else {
	memset(&t, 0, sizeof(t));
	memcpy(&t, in, len);
	t.byte[len] = 0x80;
	siv128_dbl(&ctx->d);
	siv128_xorblock(&t, &ctx->d);
	if (!EVP_MAC_update(mac_ctx, t.byte, SIV_LEN))
	goto err;
	}
	if (!EVP_MAC_final(mac_ctx, out->byte, &out_len, sizeof(out->byte))
	\|\| out_len != SIV_LEN)
	goto err;

	ret = 1;

	err:
	EVP_MAC_CTX_free(mac_ctx);
	return ret;
	}


	__owur static ossl_inline int siv128_do_encrypt(EVP_CIPHER_CTX ctx, unsigned char out,
	unsigned char const *in, size_t len,
	SIV_BLOCK *icv)
	{
	int out_len = (int)len;

	if (!EVP_CipherInit_ex(ctx, NULL, NULL, NULL, icv->byte, 1))
	return 0;
	return EVP_EncryptUpdate(ctx, out, &out_len, in, out_len);
	}

	/*
	* Create a new SIV128_CONTEXT
	*/
	SIV128_CONTEXT ossl_siv128_new(const unsigned char key, int klen,
	EVP_CIPHER cbc, EVP_CIPHER ctr,
	OSSL_LIB_CTX libctx, const char propq)
	{
	SIV128_CONTEXT *ctx;
	int ret;

	if ((ctx = OPENSSL_malloc(sizeof(*ctx))) != NULL) {
	ret = ossl_siv128_init(ctx, key, klen, cbc, ctr, libctx, propq);
	if (ret)
	return ctx;
	OPENSSL_free(ctx);
	}

	return NULL;
	}

	/*
	* Initialise an existing SIV128_CONTEXT
	*/
	int ossl_siv128_init(SIV128_CONTEXT ctx, const unsigned char key, int klen,
	const EVP_CIPHER cbc, const EVP_CIPHER ctr,
	OSSL_LIB_CTX libctx, const char propq)
	{
	static const unsigned char zero[SIV_LEN] = { 0 };
	size_t out_len = SIV_LEN;
	EVP_MAC_CTX *mac_ctx = NULL;
	OSSL_PARAM params[3];
	const char *cbc_name;

	if (ctx == NULL)
	return 0;

	memset(&ctx->d, 0, sizeof(ctx->d));
	EVP_CIPHER_CTX_free(ctx->cipher_ctx);
	EVP_MAC_CTX_free(ctx->mac_ctx_init);
	EVP_MAC_free(ctx->mac);
	ctx->mac = NULL;
	ctx->cipher_ctx = NULL;
	ctx->mac_ctx_init = NULL;

	if (key == NULL \|\| cbc == NULL \|\| ctr == NULL)
	return 0;

	cbc_name = EVP_CIPHER_name(cbc);
	params[0] = OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_CIPHER,
	(char *)cbc_name, 0);
	params[1] = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
	(void *)key, klen);
	params[2] = OSSL_PARAM_construct_end();

	if ((ctx->cipher_ctx = EVP_CIPHER_CTX_new()) == NULL
	\|\| (ctx->mac =
	EVP_MAC_fetch(libctx, OSSL_MAC_NAME_CMAC, propq)) == NULL
	\|\| (ctx->mac_ctx_init = EVP_MAC_CTX_new(ctx->mac)) == NULL
	\|\| !EVP_MAC_CTX_set_params(ctx->mac_ctx_init, params)
	\|\| !EVP_EncryptInit_ex(ctx->cipher_ctx, ctr, NULL, key + klen, NULL)
	\|\| (mac_ctx = EVP_MAC_CTX_dup(ctx->mac_ctx_init)) == NULL
	\|\| !EVP_MAC_update(mac_ctx, zero, sizeof(zero))
	\|\| !EVP_MAC_final(mac_ctx, ctx->d.byte, &out_len,
	sizeof(ctx->d.byte))) {
	EVP_CIPHER_CTX_free(ctx->cipher_ctx);
	EVP_MAC_CTX_free(ctx->mac_ctx_init);
	EVP_MAC_CTX_free(mac_ctx);
	EVP_MAC_free(ctx->mac);
	return 0;
	}
	EVP_MAC_CTX_free(mac_ctx);

	ctx->final_ret = -1;
	ctx->crypto_ok = 1;

	return 1;
	}

	/*
	* Copy an SIV128_CONTEXT object
	*/
	int ossl_siv128_copy_ctx(SIV128_CONTEXT dest, SIV128_CONTEXT src)
	{
	memcpy(&dest->d, &src->d, sizeof(src->d));
	if (dest->cipher_ctx == NULL) {
	dest->cipher_ctx = EVP_CIPHER_CTX_new();
	if (dest->cipher_ctx == NULL)
	return 0;
	}
	if (!EVP_CIPHER_CTX_copy(dest->cipher_ctx, src->cipher_ctx))
	return 0;
	EVP_MAC_CTX_free(dest->mac_ctx_init);
	dest->mac_ctx_init = EVP_MAC_CTX_dup(src->mac_ctx_init);
	if (dest->mac_ctx_init == NULL)
	return 0;
	dest->mac = src->mac;
	if (dest->mac != NULL)
	EVP_MAC_up_ref(dest->mac);
	return 1;
	}

	/*
	* Provide any AAD. This can be called multiple times.
	* Per RFC5297, the last piece of associated data
	* is the nonce, but it's not treated special
	*/
	int ossl_siv128_aad(SIV128_CONTEXT ctx, const unsigned char aad,
	size_t len)
	{
	SIV_BLOCK mac_out;
	size_t out_len = SIV_LEN;
	EVP_MAC_CTX *mac_ctx;

	siv128_dbl(&ctx->d);

	if ((mac_ctx = EVP_MAC_CTX_dup(ctx->mac_ctx_init)) == NULL
	\|\| !EVP_MAC_update(mac_ctx, aad, len)
	\|\| !EVP_MAC_final(mac_ctx, mac_out.byte, &out_len,
	sizeof(mac_out.byte))
	\|\| out_len != SIV_LEN) {
	EVP_MAC_CTX_free(mac_ctx);
	return 0;
	}
	EVP_MAC_CTX_free(mac_ctx);

	siv128_xorblock(&ctx->d, &mac_out);

	return 1;
	}

	/*
	* Provide any data to be encrypted. This can be called once.
	*/
	int ossl_siv128_encrypt(SIV128_CONTEXT *ctx,
	const unsigned char in, unsigned char out,
	size_t len)
	{
	SIV_BLOCK q;

	/* can only do one crypto operation */
	if (ctx->crypto_ok == 0)
	return 0;
	ctx->crypto_ok--;

	if (!siv128_do_s2v_p(ctx, &q, in, len))
	return 0;

	memcpy(ctx->tag.byte, &q, SIV_LEN);
	q.byte[8] &= 0x7f;
	q.byte[12] &= 0x7f;

	if (!siv128_do_encrypt(ctx->cipher_ctx, out, in, len, &q))
	return 0;
	ctx->final_ret = 0;
	return len;
	}

	/*
	* Provide any data to be decrypted. This can be called once.
	*/
	int ossl_siv128_decrypt(SIV128_CONTEXT *ctx,
	const unsigned char in, unsigned char out,
	size_t len)
	{
	unsigned char* p;
	SIV_BLOCK t, q;
	int i;

	/* can only do one crypto operation */
	if (ctx->crypto_ok == 0)
	return 0;
	ctx->crypto_ok--;

	memcpy(&q, ctx->tag.byte, SIV_LEN);
	q.byte[8] &= 0x7f;
	q.byte[12] &= 0x7f;

	if (!siv128_do_encrypt(ctx->cipher_ctx, out, in, len, &q)
	\|\| !siv128_do_s2v_p(ctx, &t, out, len))
	return 0;

	p = ctx->tag.byte;
	for (i = 0; i < SIV_LEN; i++)
	t.byte[i] ^= p[i];

	if ((t.word[0] \| t.word[1]) != 0) {
	OPENSSL_cleanse(out, len);
	return 0;
	}
	ctx->final_ret = 0;
	return len;
	}

	/*
	* Return the already calculated final result.
	*/
	int ossl_siv128_finish(SIV128_CONTEXT *ctx)
	{
	return ctx->final_ret;
	}

	/*
	* Set the tag
	*/
	int ossl_siv128_set_tag(SIV128_CONTEXT ctx, const unsigned char tag, size_t len)
	{
	if (len != SIV_LEN)
	return 0;

	/* Copy the tag from the supplied buffer */
	memcpy(ctx->tag.byte, tag, len);
	return 1;
	}

	/*
	* Retrieve the calculated tag
	*/
	int ossl_siv128_get_tag(SIV128_CONTEXT ctx, unsigned char tag, size_t len)
	{
	if (len != SIV_LEN)
	return 0;

	/* Copy the tag into the supplied buffer */
	memcpy(tag, ctx->tag.byte, len);
	return 1;
	}

	/*
	* Release all resources
	*/
	int ossl_siv128_cleanup(SIV128_CONTEXT *ctx)
	{
	if (ctx != NULL) {
	EVP_CIPHER_CTX_free(ctx->cipher_ctx);
	ctx->cipher_ctx = NULL;
	EVP_MAC_CTX_free(ctx->mac_ctx_init);
	ctx->mac_ctx_init = NULL;
	EVP_MAC_free(ctx->mac);
	ctx->mac = NULL;
	OPENSSL_cleanse(&ctx->d, sizeof(ctx->d));
	OPENSSL_cleanse(&ctx->tag, sizeof(ctx->tag));
	ctx->final_ret = -1;
	ctx->crypto_ok = 1;
	}
	return 1;
	}

	int ossl_siv128_speed(SIV128_CONTEXT *ctx, int arg)
	{
	ctx->crypto_ok = (arg == 1) ? -1 : 1;
	return 1;
	}

	#endif /* OPENSSL_NO_SIV */