Fix toxencryptsave to be consistent with new_api

Upon my own decision, the two tox_encryped_new convenience functions were removed due to basically needing two different sets of error codes.
At iphydf's suggestion the corresponding tox_get_encrypted_savedata convenience functions were removed as well.

3 files changed, 240 insertions, 339 deletions

diff --git a/auto_tests/encryptsave_test.c b/auto_tests/encryptsave_test.c
index e2f41f43..9ab29a27 100644
--- a/auto_tests/encryptsave_test.c
+++ b/auto_tests/encryptsave_test.c
@@ -55,7 +55,6 @@ END_TEST
 
 START_TEST(test_save_friend)
 {
-    TOX_ERR_ENCRYPTED_NEW err = TOX_ERR_ENCRYPTED_NEW_OK;
     Tox *tox1 = tox_new(0, 0, 0, 0);
     Tox *tox2 = tox_new(0, 0, 0, 0);
     ck_assert_msg(tox1 || tox2, "Failed to create 2 tox instances");
@@ -63,99 +62,108 @@ START_TEST(test_save_friend)
     tox_callback_friend_request(tox2, accept_friend_request, &to_compare);
     uint8_t address[TOX_ADDRESS_SIZE];
     tox_self_get_address(tox2, address);
-    int test = tox_friend_add(tox1, address, (uint8_t *)"Gentoo", 7, 0);
-    ck_assert_msg(test == 0, "Failed to add friend error code: %i", test);
+    uint32_t test = tox_friend_add(tox1, address, (uint8_t *)"Gentoo", 7, 0);
+    ck_assert_msg(test != UINT32_MAX, "Failed to add friend");
 
-    uint32_t size = tox_encrypted_size(tox1);
+    size_t size = tox_get_savedata_size(tox1);
     uint8_t data[size];
-    test = tox_encrypted_save(tox1, data, "correcthorsebatterystaple", 25);
-    ck_assert_msg(test == 0, "failed to encrypted save");
-    //ck_assert_msg(tox_is_save_encrypted(data) == 1, "magic number missing");
-
-    Tox *tox3 = tox_encrypted_new(0, data, size, "correcthorsebatterystaple", 25, &err);
-    ck_assert_msg(err == TOX_ERR_ENCRYPTED_NEW_OK, "failed to encrypted new");
+    tox_get_savedata(tox1, data);
+    size_t size2 = size + TOX_PASS_ENCRYPTION_EXTRA_LENGTH; 
+    uint8_t enc_data[size2];
+    TOX_ERR_ENCRYPTION error1;
+    bool ret = tox_pass_encrypt(data, size, "correcthorsebatterystaple", 25, enc_data, &error1);
+    ck_assert_msg(ret, "failed to encrypted save: %u", error1);
+    ck_assert_msg(tox_is_data_encrypted(enc_data), "magic number missing");
+
+    TOX_ERR_NEW err2;
+    Tox *tox3 = tox_new(0, enc_data, size2, &err2);
+    ck_assert_msg(err2 == TOX_ERR_NEW_LOAD_ENCRYPTED, "wrong error! %u. should fail with %u", err2, TOX_ERR_NEW_LOAD_ENCRYPTED);
+    uint8_t dec_data[size];
+    TOX_ERR_DECRYPTION err3;
+    ret = tox_pass_decrypt(enc_data, size2, "correcthorsebatterystaple", 25, dec_data, &err3);
+    ck_assert_msg(ret, "failed to decrypt save: %u", err3);
+    tox3 = tox_new(0, dec_data, size, &err2);
+    ck_assert_msg(err2 == TOX_ERR_NEW_OK, "failed to load from decrypted data: %u", err2);
     uint8_t address2[TOX_PUBLIC_KEY_SIZE];
-    test = tox_friend_get_public_key(tox3, 0, address2, 0);
-    ck_assert_msg(test == 1, "no friends!");
+    ret = tox_friend_get_public_key(tox3, 0, address2, 0);
+    ck_assert_msg(ret, "no friends!");
     ck_assert_msg(memcmp(address, address2, TOX_PUBLIC_KEY_SIZE) == 0, "addresses don't match!");
 
-    size = tox_encrypted_size(tox3);
+    size = tox_get_savedata_size(tox3);
     uint8_t data2[size];
+    tox_get_savedata(tox3, data2);
     uint8_t key[32 + crypto_box_BEFORENMBYTES];
     memcpy(key, salt, 32);
     memcpy(key + 32, known_key2, crypto_box_BEFORENMBYTES);
-    test = tox_encrypted_key_save(tox3, data2, key);
-    ck_assert_msg(test == 0, "failed to encrypted save the second");
-    //ck_assert_msg(tox_is_save_encrypted(data2) == 1, "magic number the second missing");
-
-    // first test tox_encrypted_key_new
-    Tox *tox4 = tox_encrypted_key_new(0, data2, size, key, &err);
-    ck_assert_msg(err == TOX_ERR_ENCRYPTED_NEW_OK, "failed to encrypted new the second");
-    uint8_t address4[TOX_PUBLIC_KEY_SIZE];
-    test = tox_friend_get_public_key(tox4, 0, address4, 0);
-    ck_assert_msg(test == 1, "no friends! the second");
-    ck_assert_msg(memcmp(address, address2, TOX_PUBLIC_KEY_SIZE) == 0, "addresses don't match! the second");
-
-    // now test compaitibilty with tox_encrypted_new, first manually...
+    size2 = size + TOX_PASS_ENCRYPTION_EXTRA_LENGTH;
+    uint8_t encdata2[size2];
+    ret = tox_pass_key_encrypt(data2, size, key, encdata2, &error1);
+    ck_assert_msg(ret, "failed to key encrypt %u", error1);
+    ck_assert_msg(tox_is_data_encrypted(encdata2), "magic number the second missing");
+
     uint8_t out1[size], out2[size];
-    //printf("Trying to decrypt from pw:\n");
-    uint32_t sz1 = tox_pass_decrypt(data2, size, pw, pwlen, out1);
-    uint32_t sz2 = tox_pass_key_decrypt(data2, size, key, out2);
-    ck_assert_msg(sz1 == sz2, "differing output sizes");
-    ck_assert_msg(memcmp(out1, out2, sz1) == 0, "differing output data");
+    ret = tox_pass_decrypt(encdata2, size2, pw, pwlen, out1, &err3);
+    ck_assert_msg(ret, "failed to pw decrypt %u", err3);
+    ret = tox_pass_key_decrypt(encdata2, size2, key, out2, &err3);
+    ck_assert_msg(ret, "failed to key decrypt %u", err3);
+    ck_assert_msg(memcmp(out1, out2, size) == 0, "differing output data");
 
     // and now with the code in use (I only bothered with manually to debug this, and it seems a waste
     // to remove the manual check now that it's there)
-    Tox *tox5 = tox_encrypted_new(0, data2, size, pw, pwlen, &err);
-    ck_assert_msg(err == TOX_ERR_ENCRYPTED_NEW_OK, "failed to encrypted new the third");
+    Tox *tox4 = tox_new(0, out1, size, &err2);
+    ck_assert_msg(err2 == TOX_ERR_NEW_OK, "failed to new the third");
     uint8_t address5[TOX_PUBLIC_KEY_SIZE];
-    test = tox_friend_get_public_key(tox4, 0, address5, 0);
-    ck_assert_msg(test == 1, "no friends! the third");
+    ret = tox_friend_get_public_key(tox4, 0, address5, 0);
+    ck_assert_msg(ret, "no friends! the third");
     ck_assert_msg(memcmp(address, address2, TOX_PUBLIC_KEY_SIZE) == 0, "addresses don't match! the third");
 
     tox_kill(tox1);
     tox_kill(tox2);
     tox_kill(tox3);
     tox_kill(tox4);
-    tox_kill(tox5);
 }
 END_TEST
 
 START_TEST(test_keys)
 {
-    uint8_t key[tox_pass_key_length()];
-    tox_derive_key_from_pass("123qweasdzxc", 12, key);
+    TOX_ERR_ENCRYPTION encerr;
+    TOX_ERR_DECRYPTION decerr;
+    TOX_ERR_KEY_DERIVATION keyerr;
+    uint8_t key[TOX_PASS_KEY_LENGTH];
+    bool ret = tox_derive_key_from_pass("123qweasdzxc", 12, key, &keyerr);
+    ck_assert_msg(ret, "generic failure 1: %u", keyerr);
     uint8_t *string = "No Patrick, mayonnaise is not an instrument."; // 44
 
-    uint8_t encrypted[44 + tox_pass_encryption_extra_length()];
-    int sz = tox_pass_key_encrypt(string, 44, key, encrypted);
-
-    uint8_t encrypted2[44 + tox_pass_encryption_extra_length()];
-    int sz2 = tox_pass_encrypt(string, 44, "123qweasdzxc", 12, encrypted2);
+    uint8_t encrypted[44 + TOX_PASS_ENCRYPTION_EXTRA_LENGTH];
+    ret = tox_pass_key_encrypt(string, 44, key, encrypted, &encerr);
+    ck_assert_msg(ret, "generic failure 2: %u", encerr);
 
-    ck_assert_msg(sz == sz2, "an encryption failed");
+    uint8_t encrypted2[44 + TOX_PASS_ENCRYPTION_EXTRA_LENGTH];
+    ret = tox_pass_encrypt(string, 44, "123qweasdzxc", 12, encrypted2, &encerr);
+    ck_assert_msg(ret, "generic failure 3: %u", encerr);
 
-    uint8_t out1[44 + tox_pass_encryption_extra_length()];
-    uint8_t out2[44 + tox_pass_encryption_extra_length()];
+    uint8_t out1[44 + TOX_PASS_ENCRYPTION_EXTRA_LENGTH];
+    uint8_t out2[44 + TOX_PASS_ENCRYPTION_EXTRA_LENGTH];
 
-    sz = tox_pass_key_decrypt(encrypted, 44 + tox_pass_encryption_extra_length(), key, out1);
-    ck_assert_msg(sz == 44, "sz isn't right");
+    ret = tox_pass_key_decrypt(encrypted, 44 + TOX_PASS_ENCRYPTION_EXTRA_LENGTH, key, out1, &decerr);
+    ck_assert_msg(ret, "generic failure 4: %u", decerr);
     ck_assert_msg(memcmp(out1, string, 44) == 0, "decryption 1 failed");
 
-    sz2 = tox_pass_decrypt(encrypted2, 44 + tox_pass_encryption_extra_length(), "123qweasdzxc", 12, out2);
-    ck_assert_msg(sz2 == 44, "sz2 isn't right");
+    ret = tox_pass_decrypt(encrypted2, 44 + TOX_PASS_ENCRYPTION_EXTRA_LENGTH, "123qweasdzxc", 12, out2, &decerr);
+    ck_assert_msg(ret, "generic failure 5: %u", &decerr);
     ck_assert_msg(memcmp(out2, string, 44) == 0, "decryption 2 failed");
 
     // test that pass_decrypt can decrypt things from pass_key_encrypt
-    sz = tox_pass_decrypt(encrypted, 44 + tox_pass_encryption_extra_length(), "123qweasdzxc", 12, out1);
-    ck_assert_msg(sz == 44, "sz isn't right");
+    ret = tox_pass_decrypt(encrypted, 44 + TOX_PASS_ENCRYPTION_EXTRA_LENGTH, "123qweasdzxc", 12, out1, &decerr);
+    ck_assert_msg(ret, "generic failure 6: %u", decerr);
     ck_assert_msg(memcmp(out1, string, 44) == 0, "decryption 3 failed");
 
-    uint8_t salt[tox_pass_salt_length()];
-    ck_assert_msg(0 == tox_get_salt(encrypted, salt), "couldn't get salt");
-    uint8_t key2[tox_pass_key_length()];
-    tox_derive_key_with_salt("123qweasdzxc", 12, salt, key2);
-    ck_assert_msg(0 == memcmp(key, key2, tox_pass_key_length()), "salt comparison failed");
+    uint8_t salt[TOX_PASS_SALT_LENGTH];
+    ck_assert_msg(tox_get_salt(encrypted, salt), "couldn't get salt");
+    uint8_t key2[TOX_PASS_KEY_LENGTH];
+    ret = tox_derive_key_with_salt("123qweasdzxc", 12, salt, key2, &keyerr);
+    ck_assert_msg(ret, "generic failure 7: %u", keyerr);
+    ck_assert_msg(0 == memcmp(key, key2, TOX_PASS_KEY_LENGTH), "salt comparison failed");
 }
 END_TEST
 
@@ -163,7 +171,7 @@ Suite *encryptsave_suite(void)
 {
     Suite *s = suite_create("encryptsave");
 
-    DEFTESTCASE_SLOW(known_kdf, 60); /* is 5-10 seconds on my computer, but is directly dependent on CPU */
+    DEFTESTCASE_SLOW(known_kdf, 60);
     DEFTESTCASE_SLOW(save_friend, 20);
     DEFTESTCASE_SLOW(keys, 30);
 
diff --git a/toxencryptsave/toxencryptsave.c b/toxencryptsave/toxencryptsave.c
index 874f0fd0..e7ec31f1 100644
--- a/toxencryptsave/toxencryptsave.c
+++ b/toxencryptsave/toxencryptsave.c
@@ -37,81 +37,68 @@
 #include <crypto_hash_sha256.h>
 #endif
 
-#define TOX_PASS_ENCRYPTION_EXTRA_LENGTH (crypto_box_MACBYTES + crypto_box_NONCEBYTES \
-           + crypto_pwhash_scryptsalsa208sha256_SALTBYTES + TOX_ENC_SAVE_MAGIC_LENGTH)
-
-#define TOX_PASS_KEY_LENGTH (crypto_pwhash_scryptsalsa208sha256_SALTBYTES + crypto_box_KEYBYTES)
-
-int tox_pass_encryption_extra_length()
-{
-    return TOX_PASS_ENCRYPTION_EXTRA_LENGTH;
-}
+#if TOX_PASS_SALT_LENGTH != crypto_pwhash_scryptsalsa208sha256_SALTBYTES
+#error TOX_PASS_SALT_LENGTH is assumed to be equal to crypto_pwhash_scryptsalsa208sha256_SALTBYTES
+#endif
 
-int tox_pass_key_length()
-{
-    return TOX_PASS_KEY_LENGTH;
-}
+#if TOX_PASS_KEY_LENGTH != (crypto_pwhash_scryptsalsa208sha256_SALTBYTES + crypto_box_KEYBYTES)
+#error TOX_PASS_KEY_LENGTH is assumed to be equal to (crypto_pwhash_scryptsalsa208sha256_SALTBYTES + crypto_box_KEYBYTES)
+#endif
 
-int tox_pass_salt_length()
-{
-    return crypto_pwhash_scryptsalsa208sha256_SALTBYTES;
-}
+#if TOX_PASS_ENCRYPTION_EXTRA_LENGTH != (crypto_box_MACBYTES + crypto_box_NONCEBYTES + crypto_pwhash_scryptsalsa208sha256_SALTBYTES + TOX_ENC_SAVE_MAGIC_LENGTH)
+#error 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)
+#endif
 
-/* This "module" provides functions analogous to tox_load and tox_save in toxcore
- * Clients should consider alerting their users that, unlike plain data, if even one bit
+/* 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.
  */
 
-/*  return size of the messenger data (for encrypted saving). */
-uint32_t tox_encrypted_size(const Tox *tox)
-{
-    return tox_get_savedata_size(tox) + TOX_PASS_ENCRYPTION_EXTRA_LENGTH;
-}
-
 /* This retrieves the salt used to encrypt the given data, which can then be passed to
  * derive_key_with_salt to produce the same key as was previously used. Any encrpyted
  * data with this module can be used as input.
  *
- * returns -1 if the magic number is wrong
- * returns 0 otherwise (no guarantee about validity of data)
+ * returns true if magic number matches
+ * success does not say anything about the validity of the data, only that data of
+ * the appropriate size was copied
  */
-int tox_get_salt(uint8_t *data, uint8_t *salt)
+bool tox_get_salt(const uint8_t *data, uint8_t *salt)
 {
     if (memcmp(data, TOX_ENC_SAVE_MAGIC_NUMBER, TOX_ENC_SAVE_MAGIC_LENGTH) != 0)
-        return -1;
+        return 0;
 
     data += TOX_ENC_SAVE_MAGIC_LENGTH;
     memcpy(salt, data, crypto_pwhash_scryptsalsa208sha256_SALTBYTES);
-    return 0;
+    return 1;
 }
 
 /* Generates a secret symmetric key from the given passphrase. out_key must be at least
  * TOX_PASS_KEY_LENGTH bytes long.
  * Be sure to not compromise the key! Only keep it in memory, do not write to disk.
- * This function is fairly cheap, but irungentoo insists that you be allowed to
- * cache the result if you want, to minimize computation for repeated encryptions.
  * The password is zeroed after key derivation.
  * The key should only be used with the other functions in this module, as it
  * includes a salt.
+ * 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. See below.
  *
- * returns 0 on success
- * returns -1 on failure
+ * returns true on success
  */
-int tox_derive_key_from_pass(uint8_t *passphrase, uint32_t pplength, uint8_t *out_key)
+bool tox_derive_key_from_pass(uint8_t *passphrase, size_t pplength, uint8_t *out_key, TOX_ERR_KEY_DERIVATION *error)
 {
     uint8_t salt[crypto_pwhash_scryptsalsa208sha256_SALTBYTES];
     randombytes(salt, sizeof salt);
-    return tox_derive_key_with_salt(passphrase, pplength, salt, out_key);
+    return tox_derive_key_with_salt(passphrase, pplength, salt, out_key, error);
 }
 
 /* Same as above, except with use the given salt for deterministic key derivation.
  * The salt must be tox_salt_length() bytes in length.
  */
-int tox_derive_key_with_salt(uint8_t *passphrase, uint32_t pplength, uint8_t *salt, uint8_t *out_key)
+bool tox_derive_key_with_salt(uint8_t *passphrase, size_t pplength, uint8_t *salt, uint8_t *out_key, TOX_ERR_KEY_DERIVATION *error)
 {
-    if (pplength == 0)
-        return -1;
+    if (pplength == 0 || !passphrase || !salt || !out_key) {
+        SET_ERROR_PARAMETER(error, TOX_ERR_KEY_DERIVATION_NULL);
+        return 0;
+    }
 
     uint8_t passkey[crypto_hash_sha256_BYTES];
     crypto_hash_sha256(passkey, passphrase, pplength);
@@ -127,27 +114,32 @@ int tox_derive_key_with_salt(uint8_t *passphrase, uint32_t pplength, uint8_t *sa
                 crypto_pwhash_scryptsalsa208sha256_OPSLIMIT_INTERACTIVE * 2, /* slightly stronger */
                 crypto_pwhash_scryptsalsa208sha256_MEMLIMIT_INTERACTIVE) != 0) {
         /* out of memory most likely */
-        return -1;
+        SET_ERROR_PARAMETER(error, TOX_ERR_KEY_DERIVATION_FAILED);
+        return 0;
     }
 
     sodium_memzero(passkey, crypto_hash_sha256_BYTES); /* wipe plaintext pw */
     memcpy(out_key, salt, crypto_pwhash_scryptsalsa208sha256_SALTBYTES);
     memcpy(out_key + crypto_pwhash_scryptsalsa208sha256_SALTBYTES, key, crypto_box_KEYBYTES);
-    return 0;
+    SET_ERROR_PARAMETER(error, TOX_ERR_KEY_DERIVATION_OK);
+    return 1;
 }
 
-/* Encrypt arbitrary with a key produced by tox_derive_key_from_pass. The output
+/* Encrypt arbitrary with a key produced by tox_derive_key_*. The output
  * array must be at least data_len + TOX_PASS_ENCRYPTION_EXTRA_LENGTH bytes long.
  * key must be TOX_PASS_KEY_LENGTH bytes.
  * If you already have a symmetric key from somewhere besides this module, simply
  * call encrypt_data_symmetric in toxcore/crypto_core directly.
  *
- *
- * returns 0 on success
- * returns -1 on failure
+ * returns true on success
  */
-int tox_pass_key_encrypt(const uint8_t *data, uint32_t data_len, const uint8_t *key, uint8_t *out)
+bool tox_pass_key_encrypt(const uint8_t *data, size_t data_len, const uint8_t *key, uint8_t *out, TOX_ERR_ENCRYPTION *error)
 {
+    if (data_len == 0 || !data || !key || !out) {
+        SET_ERROR_PARAMETER(error, TOX_ERR_ENCRYPTION_NULL);
+        return 0;
+    }
+
     /* the output data consists of, in order:
      * salt, nonce, mac, enc_data
      * where the mac is automatically prepended by the encrypt()
@@ -173,78 +165,58 @@ int tox_pass_key_encrypt(const uint8_t *data, uint32_t data_len, const uint8_t *
     /* now encrypt */
     if (encrypt_data_symmetric(key, nonce, data, data_len, out)
             != data_len + crypto_box_MACBYTES) {
-        return -1;
+        SET_ERROR_PARAMETER(error, TOX_ERR_ENCRYPTION_FAILED);
+        return 0;
     }
 
-    return 0;
+    SET_ERROR_PARAMETER(error, TOX_ERR_ENCRYPTION_OK);
+    return 1;
 }
 
 /* Encrypts the given data with the given passphrase. The output array must be
  * at least data_len + TOX_PASS_ENCRYPTION_EXTRA_LENGTH bytes long. This delegates
  * to tox_derive_key_from_pass and tox_pass_key_encrypt.
  *
- * returns 0 on success
- * returns -1 on failure
+ * returns true on success
  */
-int tox_pass_encrypt(const uint8_t *data, uint32_t data_len, uint8_t *passphrase, uint32_t pplength, uint8_t *out)
+bool tox_pass_encrypt(const uint8_t *data, size_t data_len, uint8_t *passphrase, size_t pplength, uint8_t *out, TOX_ERR_ENCRYPTION *error)
 {
     uint8_t key[TOX_PASS_KEY_LENGTH];
+    TOX_ERR_KEY_DERIVATION _error;
+
+    if (!tox_derive_key_from_pass(passphrase, pplength, key, &_error)) {
+        if (_error == TOX_ERR_KEY_DERIVATION_NULL) {
+            SET_ERROR_PARAMETER(error, TOX_ERR_ENCRYPTION_NULL);
+        } else if (_error == TOX_ERR_KEY_DERIVATION_FAILED) {
+            SET_ERROR_PARAMETER(error, TOX_ERR_ENCRYPTION_KEY_DERIVATION_FAILED);
+        }
+        return 0;
+    }
 
-    if (tox_derive_key_from_pass(passphrase, pplength, key) == -1)
-        return -1;
-
-    return tox_pass_key_encrypt(data, data_len, key, out);
-}
-
-/* Save the messenger data encrypted with the given password.
- * data must be at least tox_encrypted_size().
- *
- * returns 0 on success
- * returns -1 on failure
- */
-int tox_encrypted_save(const Tox *tox, uint8_t *data, uint8_t *passphrase, uint32_t pplength)
-{
-    /* first get plain save data */
-    uint32_t temp_size = tox_get_savedata_size(tox);
-    uint8_t temp_data[temp_size];
-    tox_get_savedata(tox, temp_data);
-
-    /* now encrypt */
-    return tox_pass_encrypt(temp_data, temp_size, passphrase, pplength, data);
-}
-
-/* Save the messenger data encrypted with the given key from tox_derive_key.
- * data must be at least tox_encrypted_size().
- *
- * returns 0 on success
- * returns -1 on failure
- */
-int tox_encrypted_key_save(const Tox *tox, uint8_t *data, uint8_t *key)
-{
-    /* first get plain save data */
-    uint32_t temp_size = tox_get_savedata_size(tox);
-    uint8_t temp_data[temp_size];
-    tox_get_savedata(tox, temp_data);
-
-    /* encrypt */
-    return tox_pass_key_encrypt(temp_data, temp_size, key, data);
+    return tox_pass_key_encrypt(data, data_len, key, out, error);
 }
 
 /* This is the inverse of tox_pass_key_encrypt, also using only keys produced by
  * tox_derive_key_from_pass.
  *
- * returns the length of the output data (== data_len - TOX_PASS_ENCRYPTION_EXTRA_LENGTH) on success
- * returns -1 on failure
+ * the output data has size data_length - TOX_PASS_ENCRYPTION_EXTRA_LENGTH
+ *
+ * returns true on success
  */
-int tox_pass_key_decrypt(const uint8_t *data, uint32_t length, const uint8_t *key, uint8_t *out)
+bool tox_pass_key_decrypt(const uint8_t *data, size_t length, const uint8_t *key, uint8_t *out, TOX_ERR_DECRYPTION *error)
 {
-    if (length <= TOX_PASS_ENCRYPTION_EXTRA_LENGTH
-            || 0 != memcmp(data, TOX_ENC_SAVE_MAGIC_NUMBER, TOX_ENC_SAVE_MAGIC_LENGTH))
-        return -1;
+    if (length <= TOX_PASS_ENCRYPTION_EXTRA_LENGTH) {
+        SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_INVALID_LENGTH);
+        return 0;
+    }
+    if (memcmp(data, TOX_ENC_SAVE_MAGIC_NUMBER, TOX_ENC_SAVE_MAGIC_LENGTH) != 0) {
+        SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_BAD_FORMAT);
+        return 0;
+    }
 
     data += TOX_ENC_SAVE_MAGIC_LENGTH;
 
-    uint32_t decrypt_length = length - TOX_PASS_ENCRYPTION_EXTRA_LENGTH;
+    size_t decrypt_length = length - TOX_PASS_ENCRYPTION_EXTRA_LENGTH;
     //uint8_t salt[crypto_pwhash_scryptsalsa208sha256_SALTBYTES];
     uint8_t nonce[crypto_box_NONCEBYTES];
 
@@ -257,20 +229,29 @@ int tox_pass_key_decrypt(const uint8_t *data, uint32_t length, const uint8_t *ke
     /* decrypt the data */
     if (decrypt_data_symmetric(key, nonce, data, decrypt_length + crypto_box_MACBYTES, out)
             != decrypt_length) {
-        return -1;
+        SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_FAILED);
+        return 0;
     }
 
-    return decrypt_length;
+    SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_OK);
+    return 1;
 }
 
 /* Decrypts the given data with the given passphrase. The output array must be
- * at least data_len - TOX_PASS_ENCRYPTION_EXTRA_LENGTH bytes long.
+ * at least data_len - TOX_PASS_ENCRYPTION_EXTRA_LENGTH bytes long. This delegates
+ * to tox_pass_key_decrypt.
+ *
+ * the output data has size data_length - TOX_PASS_ENCRYPTION_EXTRA_LENGTH
  *
- * returns the length of the output data (== data_len - TOX_PASS_ENCRYPTION_EXTRA_LENGTH) on success
- * returns -1 on failure
+ * returns true on success
  */
-int tox_pass_decrypt(const uint8_t *data, uint32_t length, uint8_t *passphrase, uint32_t pplength, uint8_t *out)
+bool tox_pass_decrypt(const uint8_t *data, size_t length, uint8_t *passphrase, size_t pplength, uint8_t *out, TOX_ERR_DECRYPTION *error)
 {
+    if (memcmp(data, TOX_ENC_SAVE_MAGIC_NUMBER, TOX_ENC_SAVE_MAGIC_LENGTH) != 0) {
+        SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_BAD_FORMAT);
+        return 0;
+    }
+
     uint8_t passkey[crypto_hash_sha256_BYTES];
     crypto_hash_sha256(passkey, passphrase, pplength);
 
@@ -286,60 +267,18 @@ int tox_pass_decrypt(const uint8_t *data, uint32_t length, uint8_t *passphrase,
                 crypto_pwhash_scryptsalsa208sha256_OPSLIMIT_INTERACTIVE * 2, /* slightly stronger */
                 crypto_pwhash_scryptsalsa208sha256_MEMLIMIT_INTERACTIVE) != 0) {
         /* out of memory most likely */
-        return -1;
+        SET_ERROR_PARAMETER(error, TOX_ERR_DECRYPTION_KEY_DERIVATION_FAILED);
+        return 0;
     }
 
     sodium_memzero(passkey, crypto_hash_sha256_BYTES); /* wipe plaintext pw */
 
-    return tox_pass_key_decrypt(data, length, key, out);
-}
-
-/* Load the new messenger from encrypted data of size length.
- * All other arguments are like toxcore/tox_new().
- *
- * returns NULL on failure; see the documentation in toxcore/tox.h.
- */
-Tox *tox_encrypted_new(const struct Tox_Options *options, const uint8_t *data, size_t length, uint8_t *passphrase,
-                       size_t pplength, TOX_ERR_ENCRYPTED_NEW *error)
-{
-    uint32_t decrypt_length = length - TOX_PASS_ENCRYPTION_EXTRA_LENGTH;
-    uint8_t temp_data[decrypt_length];
-
-    if (tox_pass_decrypt(data, length, passphrase, pplength, temp_data)
-            != decrypt_length) {
-        SET_ERROR_PARAMETER(error, TOX_ERR_ENCRYPTED_NEW_LOAD_DECRYPTION_FAILED);
-        return NULL;
-    }
-
-    return tox_new(options, temp_data, decrypt_length, error);
-}
-
-/* Load the messenger from encrypted data of size length, with key from tox_derive_key.
- * All other arguments are like toxcore/tox_new().
- *
- * returns NULL on failure; see the documentation in toxcore/tox.h.
- */
-Tox *tox_encrypted_key_new(const struct Tox_Options *options, const uint8_t *data, size_t length, uint8_t *key,
-                           TOX_ERR_ENCRYPTED_NEW *error)
-{
-    uint32_t decrypt_length = length - TOX_PASS_ENCRYPTION_EXTRA_LENGTH;
-    uint8_t temp_data[decrypt_length];
-
-    if (tox_pass_key_decrypt(data, length, key, temp_data)
-            != decrypt_length) {
-        SET_ERROR_PARAMETER(error, TOX_ERR_ENCRYPTED_NEW_LOAD_DECRYPTION_FAILED);
-        return NULL;
-    }
-
-    return tox_new(options, temp_data, decrypt_length, error);
+    return tox_pass_key_decrypt(data, length, key, out, error);
 }
 
 /* Determines whether or not the given data is encrypted (by checking the magic number)
- *
- * returns 1 if it is encrypted
- * returns 0 otherwise
  */
-int tox_is_data_encrypted(const uint8_t *data)
+bool tox_is_data_encrypted(const uint8_t *data)
 {
     if (memcmp(data, TOX_ENC_SAVE_MAGIC_NUMBER, TOX_ENC_SAVE_MAGIC_LENGTH) == 0)
         return 1;
diff --git a/toxencryptsave/toxencryptsave.h b/toxencryptsave/toxencryptsave.h
index db272592..ef1dfb5e 100644
--- a/toxencryptsave/toxencryptsave.h
+++ b/toxencryptsave/toxencryptsave.h
@@ -30,6 +30,7 @@ extern "C" {
 
 #include <stdint.h>
 #include <stddef.h>
+#include <stdbool.h>
 
 #ifndef TOX_DEFINED
 #define TOX_DEFINED
@@ -37,21 +38,11 @@ typedef struct Tox Tox;
 struct Tox_Options;
 #endif
 
-// these functions provide access to these defines in toxencryptsave.c, which
-// otherwise aren't actually available in clients...
-int tox_pass_encryption_extra_length();
+#define TOX_PASS_SALT_LENGTH 32
+#define TOX_PASS_KEY_LENGTH 64
+#define TOX_PASS_ENCRYPTION_EXTRA_LENGTH 80
 
-int tox_pass_key_length();
-
-int tox_pass_salt_length();
-
-/*  return size of the messenger data (for encrypted Messenger saving). */
-uint32_t tox_encrypted_size(const Tox *tox);
-
-/* This "module" provides functions analogous to tox_load and tox_save in toxcore,
- * as well as functions for encryption of arbitrary client data (e.g. chat logs).
- *
- * It is conceptually organized into two parts. The first part are the functions
+/* This module is conceptually organized into two parts. The first part are the functions
  * with "key" in the name. To use these functions, first derive an encryption key
  * from a password with tox_derive_key_from_pass, and use the returned key to
  * encrypt the data. The second part takes the password itself instead of the key,
@@ -61,114 +52,100 @@ uint32_t tox_encrypted_size(const Tox *tox);
  * favor using the first part intead of the second part.
  *
  * The encrypted data is prepended with a magic number, to aid validity checking
- * (no guarantees are made of course).
+ * (no guarantees are made of course). Any data to be decrypted must start with
+ * the magic number.
  *
  * 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.
  */
 
-
-/******************************* BEGIN PART 2 *******************************
- * For simplicty, the second part of the module is presented first. The API for
- * the first part is analgous, with some extra functions for key handling. If
- * your code spends too much time using these functions, consider using the part
- * 1 functions instead.
- */
-
-/* Encrypts the given data with the given passphrase. The output array must be
- * at least data_len + tox_pass_encryption_extra_length() bytes long. This delegates
- * to tox_derive_key_from_pass and tox_pass_key_encrypt.
- *
- * tox_encrypted_save() is a good example of how to use this function.
- *
- * returns 0 on success
- * returns -1 on failure
- */
-int tox_pass_encrypt(const uint8_t *data, uint32_t data_len, uint8_t *passphrase, uint32_t pplength, uint8_t *out);
-
-/* Save the messenger data encrypted with the given password.
- * data must be at least tox_encrypted_size().
- *
- * NOTE: Unlike tox_save(), this function may fail. Be sure to check its return
- * value.
- *
- * returns 0 on success
- * returns -1 on failure
- */
-int tox_encrypted_save(const Tox *tox, uint8_t *data, uint8_t *passphrase, uint32_t pplength);
-
-/* Decrypts the given data with the given passphrase. The output array must be
- * at least data_len - tox_pass_encryption_extra_length() bytes long. This delegates
- * to tox_pass_key_decrypt.
- *
- * tox_encrypted_load() is a good example of how to use this function.
- *
- * returns the length of the output data (== data_len - tox_pass_encryption_extra_length()) on success
- * returns -1 on failure
- */
-int tox_pass_decrypt(const uint8_t *data, uint32_t length, uint8_t *passphrase, uint32_t pplength, uint8_t *out);
-
-typedef enum TOX_ERR_ENCRYPTED_NEW {
-    TOX_ERR_ENCRYPTED_NEW_OK,
-    TOX_ERR_ENCRYPTED_NEW_NULL,
+typedef enum TOX_ERR_KEY_DERIVATION {
+    TOX_ERR_KEY_DERIVATION_OK,
     /**
-     * The function was unable to allocate enough memory to store the internal
-     * structures for the Tox object.
+     * Some input data, or maybe the output pointer, was null.
      */
-    TOX_ERR_ENCRYPTED_NEW_MALLOC,
+    TOX_ERR_KEY_DERIVATION_NULL,
     /**
-     * The function was unable to bind to a port. This may mean that all ports
-     * have already been bound, e.g. by other Tox instances, or it may mean
-     * a permission error. You may be able to gather more information from errno.
+     * The crypto lib was unable to derive a key from the given passphrase,
+     * which is usually a lack of memory issue. The functions accepting keys
+     * do not produce this error.
      */
-    TOX_ERR_ENCRYPTED_NEW_PORT_ALLOC,
+    TOX_ERR_KEY_DERIVATION_FAILED
+} TOX_ERR_KEY_DERIVATION;
+
+typedef enum TOX_ERR_ENCRYPTION {
+    TOX_ERR_ENCRYPTION_OK,
     /**
-     * proxy_type was invalid.
+     * Some input data, or maybe the output pointer, was null.
      */
-    TOX_ERR_ENCRYPTED_NEW_PROXY_BAD_TYPE,
+    TOX_ERR_ENCRYPTION_NULL,
     /**
-     * proxy_type was valid but the proxy_host passed had an invalid format
-     * or was NULL.
+     * The crypto lib was unable to derive a key from the given passphrase,
+     * which is usually a lack of memory issue. The functions accepting keys
+     * do not produce this error.
      */
-    TOX_ERR_ENCRYPTED_NEW_PROXY_BAD_HOST,
+    TOX_ERR_ENCRYPTION_KEY_DERIVATION_FAILED,
     /**
-     * proxy_type was valid, but the proxy_port was invalid.
+     * The encryption itself failed.
      */
-    TOX_ERR_ENCRYPTED_NEW_PROXY_BAD_PORT,
+    TOX_ERR_ENCRYPTION_FAILED
+} TOX_ERR_ENCRYPTION;
+
+typedef enum TOX_ERR_DECRYPTION {
+    TOX_ERR_DECRYPTION_OK,
+    /**
+     * Some input data, or maybe the output pointer, was null.
+     */
+    TOX_ERR_DECRYPTION_NULL,
     /**
-     * The proxy host passed could not be resolved.
+     * The input data was shorter than TOX_PASS_ENCRYPTION_EXTRA_LENGTH bytes
      */
-    TOX_ERR_ENCRYPTED_NEW_PROXY_NOT_FOUND,
+    TOX_ERR_DECRYPTION_INVALID_LENGTH,
     /**
-     * The byte array to be loaded contained an encrypted save.
+     * The input data is missing the magic number (i.e. wasn't created by this
+     * module, or is corrupted)
      */
-    TOX_ERR_ENCRYPTED_NEW_LOAD_ENCRYPTED,
+    TOX_ERR_DECRYPTION_BAD_FORMAT,
     /**
-     * The data format was invalid. This can happen when loading data that was
-     * saved by an older version of Tox, or when the data has been corrupted.
-     * When loading from badly formatted data, some data may have been loaded,
-     * and the rest is discarded. Passing an invalid length parameter also
-     * causes this error.
+     * The crypto lib was unable to derive a key from the given passphrase,
+     * which is usually a lack of memory issue. The functions accepting keys
+     * do not produce this error.
      */
-    TOX_ERR_ENCRYPTED_NEW_LOAD_BAD_FORMAT,
+    TOX_ERR_DECRYPTION_KEY_DERIVATION_FAILED,
     /**
      * The encrypted byte array could not be decrypted. Either the data was
      * corrupt or the password/key was incorrect.
-     *
-     * NOTE: This error code is only set by tox_encrypted_new() and
-     * tox_encrypted_key_new(), in the toxencryptsave module.
      */
-    TOX_ERR_ENCRYPTED_NEW_LOAD_DECRYPTION_FAILED
-} TOX_ERR_ENCRYPTED_NEW;
+    TOX_ERR_DECRYPTION_FAILED
+} TOX_ERR_DECRYPTION;
+
+
+/******************************* BEGIN PART 2 *******************************
+ * For simplicty, the second part of the module is presented first. The API for
+ * the first part is analgous, with some extra functions for key handling. If
+ * your code spends too much time using these functions, consider using the part
+ * 1 functions instead.
+ */
+
+/* Encrypts the given data with the given passphrase. The output array must be
+ * at least data_len + TOX_PASS_ENCRYPTION_EXTRA_LENGTH bytes long. This delegates
+ * to tox_derive_key_from_pass and tox_pass_key_encrypt.
+ *
+ * returns true on success
+ */
+bool tox_pass_encrypt(const uint8_t *data, size_t data_len, uint8_t *passphrase, size_t pplength, uint8_t *out, TOX_ERR_ENCRYPTION *error);
 
-/* Load the new messenger from encrypted data of size length.
- * All other arguments are like toxcore/tox_new().
+
+/* Decrypts the given data with the given passphrase. The output array must be
+ * at least data_len - TOX_PASS_ENCRYPTION_EXTRA_LENGTH bytes long. This delegates
+ * to tox_pass_key_decrypt.
+ *
+ * the output data has size data_length - TOX_PASS_ENCRYPTION_EXTRA_LENGTH
  *
- * returns NULL on failure; see the documentation in toxcore/tox.h.
+ * returns true on success
  */
-Tox *tox_encrypted_new(const struct Tox_Options *options, const uint8_t *data, size_t length, uint8_t *passphrase,
-                       size_t pplength, TOX_ERR_ENCRYPTED_NEW *error);
+bool tox_pass_decrypt(const uint8_t *data, size_t length, uint8_t *passphrase, size_t pplength, uint8_t *out, TOX_ERR_DECRYPTION *error);
 
 
 /******************************* BEGIN PART 1 *******************************
@@ -177,7 +154,7 @@ Tox *tox_encrypted_new(const struct Tox_Options *options, const uint8_t *data, s
  */
 
 /* Generates a secret symmetric key from the given passphrase. out_key must be at least
- * tox_pass_key_length() bytes long.
+ * TOX_PASS_KEY_LENGTH bytes long.
  * Be sure to not compromise the key! Only keep it in memory, do not write to disk.
  * The password is zeroed after key derivation.
  * The key should only be used with the other functions in this module, as it
@@ -185,72 +162,49 @@ Tox *tox_encrypted_new(const struct Tox_Options *options, const uint8_t *data, s
  * 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. See below.
  *
- * returns 0 on success
- * returns -1 on failure
+ * returns true on success
  */
-int tox_derive_key_from_pass(uint8_t *passphrase, uint32_t pplength, uint8_t *out_key);
+bool tox_derive_key_from_pass(uint8_t *passphrase, size_t pplength, uint8_t *out_key, TOX_ERR_KEY_DERIVATION *error);
 
 /* Same as above, except with use the given salt for deterministic key derivation.
  * The salt must be tox_salt_length() bytes in length.
  */
-int tox_derive_key_with_salt(uint8_t *passphrase, uint32_t pplength, uint8_t *salt, uint8_t *out_key);
+bool tox_derive_key_with_salt(uint8_t *passphrase, size_t pplength, uint8_t *salt, uint8_t *out_key, TOX_ERR_KEY_DERIVATION *error);
 
 /* This retrieves the salt used to encrypt the given data, which can then be passed to
  * derive_key_with_salt to produce the same key as was previously used. Any encrpyted
  * data with this module can be used as input.
  *
- * returns -1 if the magic number is wrong
- * returns 0 otherwise (no guarantee about validity of data)
+ * returns true if magic number matches
+ * success does not say anything about the validity of the data, only that data of
+ * the appropriate size was copied
  */
-int tox_get_salt(uint8_t *data, uint8_t *salt);
+bool tox_get_salt(const uint8_t *data, uint8_t *salt);
 
 /* Now come the functions that are analogous to the part 2 functions. */
 
-/* Encrypt arbitrary with a key produced by tox_derive_key_. The output
- * array must be at least data_len + tox_pass_encryption_extra_length() bytes long.
- * key must be tox_pass_key_length() bytes.
+/* Encrypt arbitrary with a key produced by tox_derive_key_*. The output
+ * array must be at least data_len + TOX_PASS_ENCRYPTION_EXTRA_LENGTH bytes long.
+ * key must be TOX_PASS_KEY_LENGTH bytes.
  * If you already have a symmetric key from somewhere besides this module, simply
  * call encrypt_data_symmetric in toxcore/crypto_core directly.
  *
- * returns 0 on success
- * returns -1 on failure
- */
-int tox_pass_key_encrypt(const uint8_t *data, uint32_t data_len, const uint8_t *key, uint8_t *out);
-
-/* Save the messenger data encrypted with the given key from tox_derive_key.
- * data must be at least tox_encrypted_size().
- *
- * NOTE: Unlike tox_save(), this function may fail. Be sure to check its return
- * value.
- *
- * returns 0 on success
- * returns -1 on failure
+ * returns true on success
  */
-int tox_encrypted_key_save(const Tox *tox, uint8_t *data, uint8_t *key);
+bool tox_pass_key_encrypt(const uint8_t *data, size_t data_len, const uint8_t *key, uint8_t *out, TOX_ERR_ENCRYPTION *error);
 
 /* This is the inverse of tox_pass_key_encrypt, also using only keys produced by
  * tox_derive_key_from_pass.
  *
- * returns the length of the output data (== data_len - tox_pass_encryption_extra_length()) on success
- * returns -1 on failure
- */
-int tox_pass_key_decrypt(const uint8_t *data, uint32_t length, const uint8_t *key, uint8_t *out);
-
-/* Load the messenger from encrypted data of size length, with key from tox_derive_key.
- * All other arguments are like toxcore/tox_new().
+ * the output data has size data_length - TOX_PASS_ENCRYPTION_EXTRA_LENGTH
  *
- * returns NULL on failure; see the documentation in toxcore/tox.h.
+ * returns true on success
  */
-Tox *tox_encrypted_key_new(const struct Tox_Options *options, const uint8_t *data, size_t length, uint8_t *key,
-                           TOX_ERR_ENCRYPTED_NEW *error);
-
+bool tox_pass_key_decrypt(const uint8_t *data, size_t length, const uint8_t *key, uint8_t *out, TOX_ERR_DECRYPTION *error);
 
 /* Determines whether or not the given data is encrypted (by checking the magic number)
- *
- * returns 1 if it is encrypted
- * returns 0 otherwise
  */
-int tox_is_data_encrypted(const uint8_t *data);
+bool tox_is_data_encrypted(const uint8_t *data);
 
 #ifdef __cplusplus
 }