/work/toxencryptsave/toxencryptsave.c

Source (jump to first uncovered line)
/* SPDX-License-Identifier: GPL-3.0-or-later
 * Copyright © 2016-2025 The TokTok team.
 * Copyright © 2013 Tox project.
 */

/**
 * Batch encryption functions.
 */
#include "toxencryptsave.h"

#include <sodium.h>

#include <stdlib.h>
#include <string.h>

#include "../toxcore/ccompat.h"
#include "../toxcore/crypto_core.h"
#include "../toxcore/mem.h"
#include "../toxcore/os_memory.h"
#include "../toxcore/os_random.h"
#include "defines.h"

static_assert(TOX_PASS_SALT_LENGTH == crypto_pwhash_scryptsalsa208sha256_SALTBYTES,
              "TOX_PASS_SALT_LENGTH is assumed to be equal to crypto_pwhash_scryptsalsa208sha256_SALTBYTES");
static_assert(TOX_PASS_KEY_LENGTH == CRYPTO_SHARED_KEY_SIZE,
              "TOX_PASS_KEY_LENGTH is assumed to be equal to CRYPTO_SHARED_KEY_SIZE");
static_assert(TOX_PASS_ENCRYPTION_EXTRA_LENGTH == (crypto_box_MACBYTES + crypto_box_NONCEBYTES +
              crypto_pwhash_scryptsalsa208sha256_SALTBYTES + TOX_ENC_SAVE_MAGIC_LENGTH),
              "TOX_PASS_ENCRYPTION_EXTRA_LENGTH is assumed to be equal to (crypto_box_MACBYTES + crypto_box_NONCEBYTES + crypto_pwhash_scryptsalsa208sha256_SALTBYTES + TOX_ENC_SAVE_MAGIC_LENGTH)");

#define SET_ERROR_PARAMETER(param, x) \
    do {                              \
        if (param != nullptr) {       \
            *param = x;               \
        }                             \
    } while (0)

uint32_t tox_pass_salt_length(void)
{
    return TOX_PASS_SALT_LENGTH;
}
uint32_t tox_pass_key_length(void)
{
    return TOX_PASS_KEY_LENGTH;
}
uint32_t tox_pass_encryption_extra_length(void)
{
    return TOX_PASS_ENCRYPTION_EXTRA_LENGTH;
}

struct Tox_Pass_Key {
    uint8_t salt[TOX_PASS_SALT_LENGTH];
    uint8_t key[TOX_PASS_KEY_LENGTH];
};

void tox_pass_key_free(Tox_Pass_Key *key)
{
    free(key);
}

/* Clients should consider alerting their users that, unlike plain data, if even one bit
 * becomes corrupted, the data will be entirely unrecoverable.
 * Ditto if they forget their password, there is no way to recover the data.
 */

/**
 * Retrieves the salt used to encrypt the given data.
 *
 * The retrieved salt can then be passed to tox_pass_key_derive_with_salt to
 * produce the same key as was previously used. Any data encrypted with this
 * module can be used as input.
 *
 * The cipher text must be at least TOX_PASS_ENCRYPTION_EXTRA_LENGTH bytes in
 * length.
 * The salt must be TOX_PASS_SALT_LENGTH bytes in length.
 * If the passed byte arrays are smaller than required, the behaviour is
 * undefined.
 *
 * If the cipher text pointer or the salt is NULL, this function returns false.
 *
 * Success does not say anything about the validity of the data, only that
 * data of the appropriate size was copied.
 *
 * @return true on success.
 */
bool tox_get_salt(
    const uint8_t ciphertext[TOX_PASS_ENCRYPTION_EXTRA_LENGTH],
    uint8_t salt[TOX_PASS_SALT_LENGTH], Tox_Err_Get_Salt *error)
{
    if (ciphertext == nullptr || salt == nullptr) {
        SET_ERROR_PARAMETER(error, TOX_ERR_GET_SALT_NULL);
        return false;
    }

    if (memcmp(ciphertext, TOX_ENC_SAVE_MAGIC_NUMBER, TOX_ENC_SAVE_MAGIC_LENGTH) != 0) {
        SET_ERROR_PARAMETER(error, TOX_ERR_GET_SALT_BAD_FORMAT);
        return false;
    }

    ciphertext += TOX_ENC_SAVE_MAGIC_LENGTH;
    memcpy(salt, ciphertext, crypto_pwhash_scryptsalsa208sha256_SALTBYTES);
    SET_ERROR_PARAMETER(error, TOX_ERR_GET_SALT_OK);
    return true;
}

/**
 * Generates a secret symmetric key from the given passphrase.
 *
 * Be sure to not compromise the key! Only keep it in memory, do not write
 * it to disk.
 *
 * Note that this function is not deterministic; to derive the same key from
 * a password, you also must know the random salt that was used. A
 * deterministic version of this function is `tox_pass_key_derive_with_salt`.
 *
 * @param passphrase The user-provided password. Can be empty.
 * @param passphrase_len The length of the password.
 *
 * @return new symmetric key on success, NULL on failure.
 */
Tox_Pass_Key *tox_pass_key_derive(
    const uint8_t passphrase[], size_t passphrase_len,
    Tox_Err_Key_Derivation *error)
{
    const Random *rng = os_random();

    if (rng == nullptr) {
        SET_ERROR_PARAMETER(error, TOX_ERR_KEY_DERIVATION_FAILED);
        return nullptr;
    }

    uint8_t salt[crypto_pwhash_scryptsalsa208sha256_SALTBYTES];
    random_bytes(rng, salt, sizeof(salt));
    return tox_pass_key_derive_with_salt(passphrase, passphrase_len, salt, error);
}

/**
 * Same as above, except use the given salt for deterministic key derivation.
 *
 * @param passphrase The user-provided password. Can be empty.
 * @param passphrase_len The length of the password.
 * @param salt An array of at least TOX_PASS_SALT_LENGTH bytes.
 *
 * @return new symmetric key on success, NULL on failure.
 */
Tox_Pass_Key *tox_pass_key_derive_with_salt(
    const uint8_t passphrase[], size_t passphrase_len,
    const uint8_t salt[TOX_PASS_SALT_LENGTH], Tox_Err_Key_Derivation *error)
{
    if (salt == nullptr || (passphrase == nullptr && passphrase_len != 0)) {
        SET_ERROR_PARAMETER(error, TOX_ERR_KEY_DERIVATION_NULL);
        return nullptr;
    }

    uint8_t passkey[crypto_hash_sha256_BYTES];
    crypto_hash_sha256(passkey, passphrase, passphrase_len);

    uint8_t key[CRYPTO_SHARED_KEY_SIZE];

    // Derive a key from the password
    // http://doc.libsodium.org/key_derivation/README.html
    // note that, according to the documentation, a generic pwhash interface will be created
    // once the pwhash competition (https://password-hashing.net/) is over */
    if (crypto_pwhash_scryptsalsa208sha256(
                key, sizeof(key), (char *)passkey, sizeof(passkey), salt,
                crypto_pwhash_scryptsalsa208sha256_OPSLIMIT_INTERACTIVE * 2, /* slightly stronger */
                crypto_pwhash_scryptsalsa208sha256_MEMLIMIT_INTERACTIVE) != 0) {
        /* out of memory most likely */
        SET_ERROR_PARAMETER(error, TOX_ERR_KEY_DERIVATION_FAILED);
        return nullptr;
    }

    crypto_memzero(passkey, crypto_hash_sha256_BYTES); /* wipe plaintext pw */

    Tox_Pass_Key *out_key = (Tox_Pass_Key *)calloc(1, sizeof(Tox_Pass_Key));

    if (out_key == nullptr) {
        SET_ERROR_PARAMETER(error, TOX_ERR_KEY_DERIVATION_FAILED);
        return nullptr;
    }

    memcpy(out_key->salt, salt, crypto_pwhash_scryptsalsa208sha256_SALTBYTES);
    memcpy(out_key->key, key, CRYPTO_SHARED_KEY_SIZE);
    SET_ERROR_PARAMETER(error, TOX_ERR_KEY_DERIVATION_OK);
    return out_key;
}

/**
 * Encrypt a plain text with a key produced by tox_pass_key_derive or
 * tox_pass_key_derive_with_salt.
 *
 * The output array must be at least
 * `plaintext_len + TOX_PASS_ENCRYPTION_EXTRA_LENGTH` bytes long.
 *
 * @param plaintext A byte array of length `plaintext_len`.
 * @param plaintext_len The length of the plain text array. Bigger than 0.
 * @param ciphertext The cipher text array to write the encrypted data to.
 *
 * @return true on success.
 */
bool tox_pass_key_encrypt(const Tox_Pass_Key *key, const uint8_t plaintext[], size_t plaintext_len,
                          uint8_t ciphertext[], Tox_Err_Encryption *error)
{
    const Memory *mem = os_memory();
    const Random *rng = os_random();

    if (mem == nullptr || rng == nullptr) {
        SET_ERROR_PARAMETER(error, TOX_ERR_ENCRYPTION_FAILED);
        return false;
    }

    if (plaintext_len == 0 || plaintext == nullptr || key == nullptr || ciphertext == nullptr) {
        SET_ERROR_PARAMETER(error, TOX_ERR_ENCRYPTION_NULL);
        return false;
    }

    // the output data consists of, in order:
    // salt, nonce, mac, enc_data
    // where the mac is automatically prepended by the encrypt()
    // the salt+nonce is called the prefix
    // I'm not sure what else I'm supposed to do with the salt and nonce, since we
    // need them to decrypt the data

    /* first add the magic number */
    memcpy(ciphertext, TOX_ENC_SAVE_MAGIC_NUMBER, TOX_ENC_SAVE_MAGIC_LENGTH);
    ciphertext += TOX_ENC_SAVE_MAGIC_LENGTH;

    /* then add the rest prefix */
    memcpy(ciphertext, key->salt, crypto_pwhash_scryptsalsa208sha256_SALTBYTES);
    ciphertext += crypto_pwhash_scryptsalsa208sha256_SALTBYTES;

    uint8_t nonce[crypto_box_NONCEBYTES];
    random_nonce(rng, nonce);
    memcpy(ciphertext, nonce, crypto_box_NONCEBYTES);
    ciphertext += crypto_box_NONCEBYTES;

    /* now encrypt */
    const int32_t encrypted_len = encrypt_data_symmetric(mem, key->key, nonce, plaintext, plaintext_len, ciphertext);
    if (encrypted_len < 0 || (size_t)encrypted_len != plaintext_len + crypto_box_MACBYTES) {
        SET_ERROR_PARAMETER(error, TOX_ERR_ENCRYPTION_FAILED);
        return false;
    }

    SET_ERROR_PARAMETER(error, TOX_ERR_ENCRYPTION_OK);
    return true;
}

/**
 * Encrypts the given data with the given passphrase.
 *
 * The output array must be at least
 * `plaintext_len + TOX_PASS_ENCRYPTION_EXTRA_LENGTH` bytes long. This delegates
 * to tox_pass_key_derive and tox_pass_key_encrypt.
 *
 * @param plaintext A byte array of length `plaintext_len`.
 * @param plaintext_len The length of the plain text array. Bigger than 0.
 * @param passphrase The user-provided password. Can be empty.
 * @param passphrase_len The length of the password.
 * @param ciphertext The cipher text array to write the encrypted data to.
 *
 * @return true on success.
 */
bool tox_pass_encrypt(const uint8_t plaintext[], size_t plaintext_len, const uint8_t passphrase[], size_t passphrase_len,
                      uint8_t ciphertext[/*! plaintext_len + TOX_PASS_ENCRYPTION_EXTRA_LENGTH */], Tox_Err_Encryption *error)
{
    Tox_Err_Key_Derivation err;
    Tox_Pass_Key *key = tox_pass_key_derive(passphrase, passphrase_len, &err);

    if (key == nullptr) {
        if (err == TOX_ERR_KEY_DERIVATION_NULL) {
            SET_ERROR_PARAMETER(error, TOX_ERR_ENCRYPTION_NULL);
        } else if (err == TOX_ERR_KEY_DERIVATION_FAILED) {
            SET_ERROR_PARAMETER(error, TOX_ERR_ENCRYPTION_KEY_DERIVATION_FAILED);
        }

        return false;
    }

    const bool result = tox_pass_key_encrypt(key, plaintext, plaintext_len, ciphertext, error);
    tox_pass_key_free(key);
    return result;
}

/**
 * This is the inverse of tox_pass_key_encrypt, also using only keys produced by
 * tox_pass_key_derive or tox_pass_key_derive_with_salt.
 *
 * @param ciphertext A byte array of length `ciphertext_len`.
 * @param ciphertext_len The length of the cipher text array. At least
 *   TOX_PASS_ENCRYPTION_EXTRA_LENGTH.
 * @param plaintext The plain text array to write the decrypted data to.
 *
 * @return true on success.
 */
bool tox_pass_key_decrypt(const Tox_Pass_Key *key, const uint8_t ciphertext[], size_t ciphertext_len,
                          uint8_t plaintext[], Tox_Err_Decryption *error)
{
    const Memory *mem = os_memory();

    if (mem == nullptr) {
        SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_FAILED);
        return false;
    }

    if (ciphertext_len <= TOX_PASS_ENCRYPTION_EXTRA_LENGTH) {
        SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_INVALID_LENGTH);
        return false;
    }

    if (ciphertext == nullptr || key == nullptr || plaintext == nullptr) {
        SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_NULL);
        return false;
    }

    if (memcmp(ciphertext, TOX_ENC_SAVE_MAGIC_NUMBER, TOX_ENC_SAVE_MAGIC_LENGTH) != 0) {
        SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_BAD_FORMAT);
        return false;
    }

    ciphertext += TOX_ENC_SAVE_MAGIC_LENGTH;
    ciphertext += crypto_pwhash_scryptsalsa208sha256_SALTBYTES; // salt only affects key derivation

    const size_t decrypt_length = ciphertext_len - TOX_PASS_ENCRYPTION_EXTRA_LENGTH;

    uint8_t nonce[crypto_box_NONCEBYTES];
    memcpy(nonce, ciphertext, crypto_box_NONCEBYTES);
    ciphertext += crypto_box_NONCEBYTES;

    /* decrypt the ciphertext */
    const int32_t decrypted_len = decrypt_data_symmetric(mem, key->key, nonce, ciphertext, decrypt_length + crypto_box_MACBYTES, plaintext);
    if (decrypted_len < 0 || (size_t)decrypted_len != decrypt_length) {
        SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_FAILED);
        return false;
    }

    SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_OK);
    return true;
}

/**
 * Decrypts the given data with the given passphrase.
 *
 * The output array must be at least
 * `ciphertext_len - TOX_PASS_ENCRYPTION_EXTRA_LENGTH` bytes long. This
 * delegates to tox_pass_key_decrypt.
 *
 * @param ciphertext A byte array of length `ciphertext_len`.
 * @param ciphertext_len The length of the cipher text array. At least
 *   TOX_PASS_ENCRYPTION_EXTRA_LENGTH.
 * @param passphrase The user-provided password. Can be empty.
 * @param passphrase_len The length of the password.
 * @param plaintext The plain text array to write the decrypted data to.
 *
 * @return true on success.
 */
bool tox_pass_decrypt(const uint8_t ciphertext[], size_t ciphertext_len, const uint8_t passphrase[],
                      size_t passphrase_len, uint8_t plaintext[/*! ciphertext_len - TOX_PASS_ENCRYPTION_EXTRA_LENGTH */], Tox_Err_Decryption *error)
{
    if (ciphertext_len <= TOX_PASS_ENCRYPTION_EXTRA_LENGTH) {
        SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_INVALID_LENGTH);
        return false;
    }

    if (ciphertext == nullptr || passphrase == nullptr || plaintext == nullptr) {
        SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_NULL);
        return false;
    }

    if (memcmp(ciphertext, TOX_ENC_SAVE_MAGIC_NUMBER, TOX_ENC_SAVE_MAGIC_LENGTH) != 0) {
        SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_BAD_FORMAT);
        return false;
    }

    uint8_t salt[crypto_pwhash_scryptsalsa208sha256_SALTBYTES];
    memcpy(salt, ciphertext + TOX_ENC_SAVE_MAGIC_LENGTH, crypto_pwhash_scryptsalsa208sha256_SALTBYTES);

    /* derive the key */
    Tox_Pass_Key *key = tox_pass_key_derive_with_salt(passphrase, passphrase_len, salt, nullptr);

    if (key == nullptr) {
        /* out of memory most likely */
        SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_KEY_DERIVATION_FAILED);
        return false;
    }

    const bool result = tox_pass_key_decrypt(key, ciphertext, ciphertext_len, plaintext, error);
    tox_pass_key_free(key);
    return result;
}

/**
 * Determines whether or not the given data is encrypted by this module.
 *
 * It does this check by verifying that the magic number is the one put in
 * place by the encryption functions.
 *
 * The data must be at least TOX_PASS_ENCRYPTION_EXTRA_LENGTH bytes in length.
 * If the passed byte array is smaller than required, the behaviour is
 * undefined.
 *
 * If the data pointer is NULL, the behaviour is undefined
 *
 * @return true if the data is encrypted by this module.
 */
bool tox_is_data_encrypted(const uint8_t data[TOX_PASS_ENCRYPTION_EXTRA_LENGTH])
{
    return memcmp(data, TOX_ENC_SAVE_MAGIC_NUMBER, TOX_ENC_SAVE_MAGIC_LENGTH) == 0;
}

const char *tox_err_key_derivation_to_string(Tox_Err_Key_Derivation error)
{
    switch (error) {
        case TOX_ERR_KEY_DERIVATION_OK:
            return "TOX_ERR_KEY_DERIVATION_OK";
        case TOX_ERR_KEY_DERIVATION_NULL:
            return "TOX_ERR_KEY_DERIVATION_NULL";
        case TOX_ERR_KEY_DERIVATION_FAILED:
            return "TOX_ERR_KEY_DERIVATION_FAILED";
    }
    return "<invalid Tox_Err_Key_Derivation>";
}

const char *tox_err_encryption_to_string(Tox_Err_Encryption error)
{
    switch (error) {
        case TOX_ERR_ENCRYPTION_OK:
            return "TOX_ERR_ENCRYPTION_OK";
        case TOX_ERR_ENCRYPTION_NULL:
            return "TOX_ERR_ENCRYPTION_NULL";
        case TOX_ERR_ENCRYPTION_KEY_DERIVATION_FAILED:
            return "TOX_ERR_ENCRYPTION_KEY_DERIVATION_FAILED";
        case TOX_ERR_ENCRYPTION_FAILED:
            return "TOX_ERR_ENCRYPTION_FAILED";
    }
    return "<invalid Tox_Err_Encryption>";
}

const char *tox_err_decryption_to_string(Tox_Err_Decryption error)
{
    switch (error) {
        case TOX_ERR_DECRYPTION_OK:
            return "TOX_ERR_DECRYPTION_OK";
        case TOX_ERR_DECRYPTION_NULL:
            return "TOX_ERR_DECRYPTION_NULL";
        case TOX_ERR_DECRYPTION_INVALID_LENGTH:
            return "TOX_ERR_DECRYPTION_INVALID_LENGTH";
        case TOX_ERR_DECRYPTION_BAD_FORMAT:
            return "TOX_ERR_DECRYPTION_BAD_FORMAT";
        case TOX_ERR_DECRYPTION_KEY_DERIVATION_FAILED:
            return "TOX_ERR_DECRYPTION_KEY_DERIVATION_FAILED";
        case TOX_ERR_DECRYPTION_FAILED:
            return "TOX_ERR_DECRYPTION_FAILED";
    }
    return "<invalid Tox_Err_Decryption>";
}

const char *tox_err_get_salt_to_string(Tox_Err_Get_Salt error)
{
    switch (error) {
        case TOX_ERR_GET_SALT_OK:
            return "TOX_ERR_GET_SALT_OK";
        case TOX_ERR_GET_SALT_NULL:
            return "TOX_ERR_GET_SALT_NULL";
        case TOX_ERR_GET_SALT_BAD_FORMAT:
            return "TOX_ERR_GET_SALT_BAD_FORMAT";
    }
    return "<invalid Tox_Err_Get_Salt>";
}

Coverage Report

Created: 2025-10-08 19:34

Line	Count	Source (jump to first uncovered line)
1		/* SPDX-License-Identifier: GPL-3.0-or-later
2		* Copyright © 2016-2025 The TokTok team.
3		* Copyright © 2013 Tox project.
4		*/
5
6		/**
7		* Batch encryption functions.
8		*/
9		#include "toxencryptsave.h"
10
11		#include <sodium.h>
12
13		#include <stdlib.h>
14		#include <string.h>
15
16		#include "../toxcore/ccompat.h"
17		#include "../toxcore/crypto_core.h"
18		#include "../toxcore/mem.h"
19		#include "../toxcore/os_memory.h"
20		#include "../toxcore/os_random.h"
21		#include "defines.h"
22
23		static_assert(TOX_PASS_SALT_LENGTH == crypto_pwhash_scryptsalsa208sha256_SALTBYTES,
24		"TOX_PASS_SALT_LENGTH is assumed to be equal to crypto_pwhash_scryptsalsa208sha256_SALTBYTES");
25		static_assert(TOX_PASS_KEY_LENGTH == CRYPTO_SHARED_KEY_SIZE,
26		"TOX_PASS_KEY_LENGTH is assumed to be equal to CRYPTO_SHARED_KEY_SIZE");
27		static_assert(TOX_PASS_ENCRYPTION_EXTRA_LENGTH == (crypto_box_MACBYTES + crypto_box_NONCEBYTES +
28		crypto_pwhash_scryptsalsa208sha256_SALTBYTES + TOX_ENC_SAVE_MAGIC_LENGTH),
29		"TOX_PASS_ENCRYPTION_EXTRA_LENGTH is assumed to be equal to (crypto_box_MACBYTES + crypto_box_NONCEBYTES + crypto_pwhash_scryptsalsa208sha256_SALTBYTES + TOX_ENC_SAVE_MAGIC_LENGTH)");
30
31		#define SET_ERROR_PARAMETER(param, x) \
32	179	do { \
33	179	if (param != nullptr) { \
34	138	*param = x; \
35	138	} \
36	179	} while (0)
37
38		uint32_t tox_pass_salt_length(void)
39	0	{
40	0	return TOX_PASS_SALT_LENGTH;
41	0	}
42		uint32_t tox_pass_key_length(void)
43	0	{
44	0	return TOX_PASS_KEY_LENGTH;
45	0	}
46		uint32_t tox_pass_encryption_extra_length(void)
47	0	{
48	0	return TOX_PASS_ENCRYPTION_EXTRA_LENGTH;
49	0	}
50
51		struct Tox_Pass_Key {
52		uint8_t salt[TOX_PASS_SALT_LENGTH];
53		uint8_t key[TOX_PASS_KEY_LENGTH];
54		};
55
56		void tox_pass_key_free(Tox_Pass_Key *key)
57	86	{
58	86	free(key);
59	86	}
60
61		/* Clients should consider alerting their users that, unlike plain data, if even one bit
62		* becomes corrupted, the data will be entirely unrecoverable.
63		* Ditto if they forget their password, there is no way to recover the data.
64		*/
65
66		/**
67		* Retrieves the salt used to encrypt the given data.
68		*
69		* The retrieved salt can then be passed to tox_pass_key_derive_with_salt to
70		* produce the same key as was previously used. Any data encrypted with this
71		* module can be used as input.
72		*
73		* The cipher text must be at least TOX_PASS_ENCRYPTION_EXTRA_LENGTH bytes in
74		* length.
75		* The salt must be TOX_PASS_SALT_LENGTH bytes in length.
76		* If the passed byte arrays are smaller than required, the behaviour is
77		* undefined.
78		*
79		* If the cipher text pointer or the salt is NULL, this function returns false.
80		*
81		* Success does not say anything about the validity of the data, only that
82		* data of the appropriate size was copied.
83		*
84		* @return true on success.
85		*/
86		bool tox_get_salt(
87		const uint8_t ciphertext[TOX_PASS_ENCRYPTION_EXTRA_LENGTH],
88		uint8_t salt[TOX_PASS_SALT_LENGTH], Tox_Err_Get_Salt *error)
89	1	{
90	1	if (ciphertext == nullptr \|\| salt == nullptr) {
91	0	SET_ERROR_PARAMETER(error, TOX_ERR_GET_SALT_NULL);
92	0	return false;
93	0	}
94
95	1	if (memcmp(ciphertext, TOX_ENC_SAVE_MAGIC_NUMBER, TOX_ENC_SAVE_MAGIC_LENGTH) != 0) {
96	0	SET_ERROR_PARAMETER(error, TOX_ERR_GET_SALT_BAD_FORMAT);
97	0	return false;
98	0	}
99
100	1	ciphertext += TOX_ENC_SAVE_MAGIC_LENGTH;
101	1	memcpy(salt, ciphertext, crypto_pwhash_scryptsalsa208sha256_SALTBYTES);
102	1	SET_ERROR_PARAMETER(error, TOX_ERR_GET_SALT_OK);
103	1	return true;
104	1	}
105
106		/**
107		* Generates a secret symmetric key from the given passphrase.
108		*
109		* Be sure to not compromise the key! Only keep it in memory, do not write
110		* it to disk.
111		*
112		* Note that this function is not deterministic; to derive the same key from
113		* a password, you also must know the random salt that was used. A
114		* deterministic version of this function is `tox_pass_key_derive_with_salt`.
115		*
116		* @param passphrase The user-provided password. Can be empty.
117		* @param passphrase_len The length of the password.
118		*
119		* @return new symmetric key on success, NULL on failure.
120		*/
121		Tox_Pass_Key *tox_pass_key_derive(
122		const uint8_t passphrase[], size_t passphrase_len,
123		Tox_Err_Key_Derivation *error)
124	46	{
125	46	const Random *rng = os_random();
126
127	46	if (rng == nullptr) {
128	0	SET_ERROR_PARAMETER(error, TOX_ERR_KEY_DERIVATION_FAILED);
129	0	return nullptr;
130	0	}
131
132	46	uint8_t salt[crypto_pwhash_scryptsalsa208sha256_SALTBYTES];
133	46	random_bytes(rng, salt, sizeof(salt));
134	46	return tox_pass_key_derive_with_salt(passphrase, passphrase_len, salt, error);
135	46	}
136
137		/**
138		* Same as above, except use the given salt for deterministic key derivation.
139		*
140		* @param passphrase The user-provided password. Can be empty.
141		* @param passphrase_len The length of the password.
142		* @param salt An array of at least TOX_PASS_SALT_LENGTH bytes.
143		*
144		* @return new symmetric key on success, NULL on failure.
145		*/
146		Tox_Pass_Key *tox_pass_key_derive_with_salt(
147		const uint8_t passphrase[], size_t passphrase_len,
148		const uint8_t salt[TOX_PASS_SALT_LENGTH], Tox_Err_Key_Derivation *error)
149	88	{
150	88	if (salt == nullptr \|\| (passphrase == nullptr && passphrase_len != 0)) {
151	0	SET_ERROR_PARAMETER(error, TOX_ERR_KEY_DERIVATION_NULL);
152	0	return nullptr;
153	0	}
154
155	88	uint8_t passkey[crypto_hash_sha256_BYTES];
156	88	crypto_hash_sha256(passkey, passphrase, passphrase_len);
157
158	88	uint8_t key[CRYPTO_SHARED_KEY_SIZE];
159
160		// Derive a key from the password
161		// http://doc.libsodium.org/key_derivation/README.html
162		// note that, according to the documentation, a generic pwhash interface will be created
163		// once the pwhash competition (https://password-hashing.net/) is over */
164	88	if (crypto_pwhash_scryptsalsa208sha256(
165	88	key, sizeof(key), (char *)passkey, sizeof(passkey), salt,
166	88	crypto_pwhash_scryptsalsa208sha256_OPSLIMIT_INTERACTIVE * 2, /* slightly stronger */
167	88	crypto_pwhash_scryptsalsa208sha256_MEMLIMIT_INTERACTIVE) != 0) {
168		/* out of memory most likely */
169	0	SET_ERROR_PARAMETER(error, TOX_ERR_KEY_DERIVATION_FAILED);
170	0	return nullptr;
171	0	}
172
173	88	crypto_memzero(passkey, crypto_hash_sha256_BYTES); /* wipe plaintext pw */
174
175	88	Tox_Pass_Key out_key = (Tox_Pass_Key )calloc(1, sizeof(Tox_Pass_Key));
176
177	88	if (out_key == nullptr) {
178	2	SET_ERROR_PARAMETER(error, TOX_ERR_KEY_DERIVATION_FAILED);
179	2	return nullptr;
180	2	}
181
182	86	memcpy(out_key->salt, salt, crypto_pwhash_scryptsalsa208sha256_SALTBYTES);
183	86	memcpy(out_key->key, key, CRYPTO_SHARED_KEY_SIZE);
184	86	SET_ERROR_PARAMETER(error, TOX_ERR_KEY_DERIVATION_OK);
185	86	return out_key;
186	88	}
187
188		/**
189		* Encrypt a plain text with a key produced by tox_pass_key_derive or
190		* tox_pass_key_derive_with_salt.
191		*
192		* The output array must be at least
193		* `plaintext_len + TOX_PASS_ENCRYPTION_EXTRA_LENGTH` bytes long.
194		*
195		* @param plaintext A byte array of length `plaintext_len`.
196		* @param plaintext_len The length of the plain text array. Bigger than 0.
197		* @param ciphertext The cipher text array to write the encrypted data to.
198		*
199		* @return true on success.
200		*/
201		bool tox_pass_key_encrypt(const Tox_Pass_Key *key, const uint8_t plaintext[], size_t plaintext_len,
202		uint8_t ciphertext[], Tox_Err_Encryption *error)
203	45	{
204	45	const Memory *mem = os_memory();
205	45	const Random *rng = os_random();
206
207	45	if (mem == nullptr \|\| rng == nullptr) {
208	0	SET_ERROR_PARAMETER(error, TOX_ERR_ENCRYPTION_FAILED);
209	0	return false;
210	0	}
211
212	45	if (plaintext_len == 0 \|\| plaintext == nullptr \|\| key == nullptr \|\| ciphertext == nullptr) {
213	0	SET_ERROR_PARAMETER(error, TOX_ERR_ENCRYPTION_NULL);
214	0	return false;
215	0	}
216
217		// the output data consists of, in order:
218		// salt, nonce, mac, enc_data
219		// where the mac is automatically prepended by the encrypt()
220		// the salt+nonce is called the prefix
221		// I'm not sure what else I'm supposed to do with the salt and nonce, since we
222		// need them to decrypt the data
223
224		/* first add the magic number */
225	45	memcpy(ciphertext, TOX_ENC_SAVE_MAGIC_NUMBER, TOX_ENC_SAVE_MAGIC_LENGTH);
226	45	ciphertext += TOX_ENC_SAVE_MAGIC_LENGTH;
227
228		/* then add the rest prefix */
229	45	memcpy(ciphertext, key->salt, crypto_pwhash_scryptsalsa208sha256_SALTBYTES);
230	45	ciphertext += crypto_pwhash_scryptsalsa208sha256_SALTBYTES;
231
232	45	uint8_t nonce[crypto_box_NONCEBYTES];
233	45	random_nonce(rng, nonce);
234	45	memcpy(ciphertext, nonce, crypto_box_NONCEBYTES);
235	45	ciphertext += crypto_box_NONCEBYTES;
236
237		/* now encrypt */
238	45	const int32_t encrypted_len = encrypt_data_symmetric(mem, key->key, nonce, plaintext, plaintext_len, ciphertext);
239	45	if (encrypted_len < 0 \|\| (size_t)encrypted_len != plaintext_len + crypto_box_MACBYTES) {
240	1	SET_ERROR_PARAMETER(error, TOX_ERR_ENCRYPTION_FAILED);
241	1	return false;
242	1	}
243
244	44	SET_ERROR_PARAMETER(error, TOX_ERR_ENCRYPTION_OK);
245	44	return true;
246	45	}
247
248		/**
249		* Encrypts the given data with the given passphrase.
250		*
251		* The output array must be at least
252		* `plaintext_len + TOX_PASS_ENCRYPTION_EXTRA_LENGTH` bytes long. This delegates
253		* to tox_pass_key_derive and tox_pass_key_encrypt.
254		*
255		* @param plaintext A byte array of length `plaintext_len`.
256		* @param plaintext_len The length of the plain text array. Bigger than 0.
257		* @param passphrase The user-provided password. Can be empty.
258		* @param passphrase_len The length of the password.
259		* @param ciphertext The cipher text array to write the encrypted data to.
260		*
261		* @return true on success.
262		*/
263		bool tox_pass_encrypt(const uint8_t plaintext[], size_t plaintext_len, const uint8_t passphrase[], size_t passphrase_len,
264		uint8_t ciphertext[/! plaintext_len + TOX_PASS_ENCRYPTION_EXTRA_LENGTH /], Tox_Err_Encryption *error)
265	44	{
266	44	Tox_Err_Key_Derivation err;
267	44	Tox_Pass_Key *key = tox_pass_key_derive(passphrase, passphrase_len, &err);
268
269	44	if (key == nullptr) {
270	1	if (err == TOX_ERR_KEY_DERIVATION_NULL) {
271	0	SET_ERROR_PARAMETER(error, TOX_ERR_ENCRYPTION_NULL);
272	1	} else if (err == TOX_ERR_KEY_DERIVATION_FAILED) {
273	1	SET_ERROR_PARAMETER(error, TOX_ERR_ENCRYPTION_KEY_DERIVATION_FAILED);
274	1	}
275
276	1	return false;
277	1	}
278
279	43	const bool result = tox_pass_key_encrypt(key, plaintext, plaintext_len, ciphertext, error);
280	43	tox_pass_key_free(key);
281	43	return result;
282	44	}
283
284		/**
285		* This is the inverse of tox_pass_key_encrypt, also using only keys produced by
286		* tox_pass_key_derive or tox_pass_key_derive_with_salt.
287		*
288		* @param ciphertext A byte array of length `ciphertext_len`.
289		* @param ciphertext_len The length of the cipher text array. At least
290		* TOX_PASS_ENCRYPTION_EXTRA_LENGTH.
291		* @param plaintext The plain text array to write the decrypted data to.
292		*
293		* @return true on success.
294		*/
295		bool tox_pass_key_decrypt(const Tox_Pass_Key *key, const uint8_t ciphertext[], size_t ciphertext_len,
296		uint8_t plaintext[], Tox_Err_Decryption *error)
297	42	{
298	42	const Memory *mem = os_memory();
299
300	42	if (mem == nullptr) {
301	0	SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_FAILED);
302	0	return false;
303	0	}
304
305	42	if (ciphertext_len <= TOX_PASS_ENCRYPTION_EXTRA_LENGTH) {
306	0	SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_INVALID_LENGTH);
307	0	return false;
308	0	}
309
310	42	if (ciphertext == nullptr \|\| key == nullptr \|\| plaintext == nullptr) {
311	0	SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_NULL);
312	0	return false;
313	0	}
314
315	42	if (memcmp(ciphertext, TOX_ENC_SAVE_MAGIC_NUMBER, TOX_ENC_SAVE_MAGIC_LENGTH) != 0) {
316	0	SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_BAD_FORMAT);
317	0	return false;
318	0	}
319
320	42	ciphertext += TOX_ENC_SAVE_MAGIC_LENGTH;
321	42	ciphertext += crypto_pwhash_scryptsalsa208sha256_SALTBYTES; // salt only affects key derivation
322
323	42	const size_t decrypt_length = ciphertext_len - TOX_PASS_ENCRYPTION_EXTRA_LENGTH;
324
325	42	uint8_t nonce[crypto_box_NONCEBYTES];
326	42	memcpy(nonce, ciphertext, crypto_box_NONCEBYTES);
327	42	ciphertext += crypto_box_NONCEBYTES;
328
329		/* decrypt the ciphertext */
330	42	const int32_t decrypted_len = decrypt_data_symmetric(mem, key->key, nonce, ciphertext, decrypt_length + crypto_box_MACBYTES, plaintext);
331	42	if (decrypted_len < 0 \|\| (size_t)decrypted_len != decrypt_length) {
332	1	SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_FAILED);
333	1	return false;
334	1	}
335
336	41	SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_OK);
337	41	return true;
338	42	}
339
340		/**
341		* Decrypts the given data with the given passphrase.
342		*
343		* The output array must be at least
344		* `ciphertext_len - TOX_PASS_ENCRYPTION_EXTRA_LENGTH` bytes long. This
345		* delegates to tox_pass_key_decrypt.
346		*
347		* @param ciphertext A byte array of length `ciphertext_len`.
348		* @param ciphertext_len The length of the cipher text array. At least
349		* TOX_PASS_ENCRYPTION_EXTRA_LENGTH.
350		* @param passphrase The user-provided password. Can be empty.
351		* @param passphrase_len The length of the password.
352		* @param plaintext The plain text array to write the decrypted data to.
353		*
354		* @return true on success.
355		*/
356		bool tox_pass_decrypt(const uint8_t ciphertext[], size_t ciphertext_len, const uint8_t passphrase[],
357		size_t passphrase_len, uint8_t plaintext[/! ciphertext_len - TOX_PASS_ENCRYPTION_EXTRA_LENGTH /], Tox_Err_Decryption *error)
358	42	{
359	42	if (ciphertext_len <= TOX_PASS_ENCRYPTION_EXTRA_LENGTH) {
360	0	SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_INVALID_LENGTH);
361	0	return false;
362	0	}
363
364	42	if (ciphertext == nullptr \|\| passphrase == nullptr \|\| plaintext == nullptr) {
365	1	SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_NULL);
366	1	return false;
367	1	}
368
369	41	if (memcmp(ciphertext, TOX_ENC_SAVE_MAGIC_NUMBER, TOX_ENC_SAVE_MAGIC_LENGTH) != 0) {
370	0	SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_BAD_FORMAT);
371	0	return false;
372	0	}
373
374	41	uint8_t salt[crypto_pwhash_scryptsalsa208sha256_SALTBYTES];
375	41	memcpy(salt, ciphertext + TOX_ENC_SAVE_MAGIC_LENGTH, crypto_pwhash_scryptsalsa208sha256_SALTBYTES);
376
377		/* derive the key */
378	41	Tox_Pass_Key *key = tox_pass_key_derive_with_salt(passphrase, passphrase_len, salt, nullptr);
379
380	41	if (key == nullptr) {
381		/* out of memory most likely */
382	1	SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_KEY_DERIVATION_FAILED);
383	1	return false;
384	1	}
385
386	40	const bool result = tox_pass_key_decrypt(key, ciphertext, ciphertext_len, plaintext, error);
387	40	tox_pass_key_free(key);
388	40	return result;
389	41	}
390
391		/**
392		* Determines whether or not the given data is encrypted by this module.
393		*
394		* It does this check by verifying that the magic number is the one put in
395		* place by the encryption functions.
396		*
397		* The data must be at least TOX_PASS_ENCRYPTION_EXTRA_LENGTH bytes in length.
398		* If the passed byte array is smaller than required, the behaviour is
399		* undefined.
400		*
401		* If the data pointer is NULL, the behaviour is undefined
402		*
403		* @return true if the data is encrypted by this module.
404		*/
405		bool tox_is_data_encrypted(const uint8_t data[TOX_PASS_ENCRYPTION_EXTRA_LENGTH])
406	2	{
407	2	return memcmp(data, TOX_ENC_SAVE_MAGIC_NUMBER, TOX_ENC_SAVE_MAGIC_LENGTH) == 0;
408	2	}
409
410		const char *tox_err_key_derivation_to_string(Tox_Err_Key_Derivation error)
411	0	{
412	0	switch (error) {
413	0	case TOX_ERR_KEY_DERIVATION_OK:
414	0	return "TOX_ERR_KEY_DERIVATION_OK";
415	0	case TOX_ERR_KEY_DERIVATION_NULL:
416	0	return "TOX_ERR_KEY_DERIVATION_NULL";
417	0	case TOX_ERR_KEY_DERIVATION_FAILED:
418	0	return "TOX_ERR_KEY_DERIVATION_FAILED";
419	0	}
420	0	return "<invalid Tox_Err_Key_Derivation>";
421	0	}
422
423		const char *tox_err_encryption_to_string(Tox_Err_Encryption error)
424	0	{
425	0	switch (error) {
426	0	case TOX_ERR_ENCRYPTION_OK:
427	0	return "TOX_ERR_ENCRYPTION_OK";
428	0	case TOX_ERR_ENCRYPTION_NULL:
429	0	return "TOX_ERR_ENCRYPTION_NULL";
430	0	case TOX_ERR_ENCRYPTION_KEY_DERIVATION_FAILED:
431	0	return "TOX_ERR_ENCRYPTION_KEY_DERIVATION_FAILED";
432	0	case TOX_ERR_ENCRYPTION_FAILED:
433	0	return "TOX_ERR_ENCRYPTION_FAILED";
434	0	}
435	0	return "<invalid Tox_Err_Encryption>";
436	0	}
437
438		const char *tox_err_decryption_to_string(Tox_Err_Decryption error)
439	2	{
440	2	switch (error) {
441	0	case TOX_ERR_DECRYPTION_OK:
442	0	return "TOX_ERR_DECRYPTION_OK";
443	0	case TOX_ERR_DECRYPTION_NULL:
444	0	return "TOX_ERR_DECRYPTION_NULL";
445	0	case TOX_ERR_DECRYPTION_INVALID_LENGTH:
446	0	return "TOX_ERR_DECRYPTION_INVALID_LENGTH";
447	0	case TOX_ERR_DECRYPTION_BAD_FORMAT:
448	0	return "TOX_ERR_DECRYPTION_BAD_FORMAT";
449	1	case TOX_ERR_DECRYPTION_KEY_DERIVATION_FAILED:
450	1	return "TOX_ERR_DECRYPTION_KEY_DERIVATION_FAILED";
451	1	case TOX_ERR_DECRYPTION_FAILED:
452	1	return "TOX_ERR_DECRYPTION_FAILED";
453	2	}
454	0	return "<invalid Tox_Err_Decryption>";
455	2	}
456
457		const char *tox_err_get_salt_to_string(Tox_Err_Get_Salt error)
458	0	{
459	0	switch (error) {
460	0	case TOX_ERR_GET_SALT_OK:
461	0	return "TOX_ERR_GET_SALT_OK";
462	0	case TOX_ERR_GET_SALT_NULL:
463	0	return "TOX_ERR_GET_SALT_NULL";
464	0	case TOX_ERR_GET_SALT_BAD_FORMAT:
465	0	return "TOX_ERR_GET_SALT_BAD_FORMAT";
466	0	}
467	0	return "<invalid Tox_Err_Get_Salt>";
468	0	}