Hello,

Thank you for the link.
Yes, I can cut the first 16 bytes off, but things get more complicated if I try vice versa scenario - to encrypt password on outside of kamailio and then decrypt it in kamailio using crypto_aes_decrypt

For example, I have a PHP method to encrypt passwords:

public function encrypt($password) {
      $keyLength = 32;
      $iterations = 5; //https://github.com/kamailio/kamailio/blob/master/src/modules/crypto/crypto_aes.c#L79
      $nonce = 'AQLlFx36iCWO4JwJ';
      var_dump(base64_encode($nonce));
      $prepared_key = openssl_pbkdf2(getenv('ENCRYPTION_KEY'), null, $keyLength, $iterations); //ENCRYPTION_KEY == aFrHumvUSb24LbMwrSyUt2TZEakhSAFS
      return openssl_encrypt(
            $password,
            'AES-256-CBC',
            $prepared_key,
            null,
            $nonce
      );
}

Encrypting string kamailio_qwerty123 using this method gives me:
Nonce/IV: QVFMbEZ4MzZpQ1dPNEp3Sg==
Passphrase: +JqKBJC99PIo5gDS1x35SONeslxH90l8FB4nVpKdJcw=

Encrypting the same string kamailio_qwerty123 using crypto_aes_encrypt gives:
QVFMbEZ4MzZpQ1dPNEp3Sju/bdBKyeVCEgiRrvpBdGs36brwNM+VqNmAzbeQTiy7


On kamailio side I have:
#!ifdef WITH_CRYPTO
modparam("crypto", "salt", "")
modparam("crypto", "key_derivation", 0)
modparam("crypto", "init_vector", "QVFMbEZ4MzZpQ1dPNEp3Sg==") # which is base64 of AQLlFx36iCWO4JwJ
#!endif

crypto_aes_decrypt("$avp(secret_encrypted)", "YUZySHVtdlVTYjI0TGJNd3JTeVV0MlRaRWFraFNBRlM=", "$var(decrypted)");

YUZySHVtdlVTYjI0TGJNd3JTeVV0MlRaRWFraFNBRlM= is base64 of aFrHumvUSb24LbMwrSyUt2TZEakhSAFS (if I got it right kamailio xpects base64 encoded password here: https://github.com/kamailio/kamailio/blob/master/src/modules/crypto/crypto_mod.c#L501)

I noticed that first part of kamailio result is quite similar to nonce returned by PHP, but even if I glue together nonce+passphrase, kamailio is unable to decrypt resulting string:

QVFMbEZ4MzZpQ1dPNEp3Sg+JqKBJC99PIo5gDS1x35SONeslxH90l8FB4nVpKdJcw

Jan 10 00:38:43 kamailio docker[9648]:  7(13) exec: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} *** cfgtrace:dbg_cfg_trace(): request_route=[AUTH] c=[/etc/kamailio/kamailio.cfg] l=1260 a=27 n=crypto_aes_decrypt
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:108]: crypto_aes_init(): got 256 bytes key
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 61, iv: 9
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 46, iv: d7
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 72, iv: e7
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 48, iv: 53
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 75, iv: 79
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 6d, iv: 4
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 76, iv: f
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 55, iv: 66
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 53, iv: cf
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 62, iv: c9
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 32, iv: e
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 34, iv: 5c
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 4c, iv: cb
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 62, iv: b5
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 4d, iv: 6a
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 77, iv: 24
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 72, iv: 0
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 53, iv: 0
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 79, iv: 0
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 55, iv: 0
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 74, iv: 0
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 32, iv: 0
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 54, iv: 0
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 5a, iv: 0
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 45, iv: 0
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 61, iv: 0
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 6b, iv: 0
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 68, iv: 0
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 53, iv: 0
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 41, iv: 0
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 46, iv: 0
Jan 10 00:38:43 kamailio docker[9648]:  7(13) DEBUG: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:114]: crypto_aes_init(): key: 53, iv: 0
Jan 10 00:38:43 kamailio docker[9648]:  7(13) ERROR: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_aes.c:198]: crypto_aes_decrypt(): failure in EVP_DecryptFinal_ex
Jan 10 00:38:43 kamailio docker[9648]:  7(13) ERROR: {1 35307 REGISTER 7ca65165-8cde0e95@10.128.150.18} crypto [crypto_mod.c:531]: ki_crypto_aes_decrypt_helper(): AES decryption failed

Please advice, maybe I am missing something here.

Best regards,
Arsenijs


From: Henning Westerholt <hw@gilawa.com>
Sent: Monday, January 9, 2023 18:52
To: Arsenijs Kabihno <a.kabihno@dynatech.lv>; sr-users@lists.kamailio.org <sr-users@lists.kamailio.org>
Subject: RE: Kamailio Crypto module and 3rd party openssl
 

Hello,

 

maybe just try to cut the first bytes off, or specify it in the PHP function.

 

This (random) web site looks a bit more similar for what the Kamailio is doing, maybe you can give it a try:

 

https://www.meridianoutpost.com/resources/etools/php-functions/php-openssl-decrypt.php

 

Cheers,

 

Henning

 

--

Henning Westerholt – https://skalatan.de/blog/

Kamailio services – https://gilawa.com

 

From: Arsenijs Kabihno <a.kabihno@dynatech.lv>
Sent: Monday, January 9, 2023 5:28 PM
To: sr-users@lists.kamailio.org
Cc: Henning Westerholt <hw@gilawa.com>
Subject: Re: Kamailio Crypto module and 3rd party openssl

 

Hello and thank you!

 

Yes, I did tried that, but unfortunately it doesn't change the way how 3rd party openssl decrypted string looks, the only difference is that in case of fixed IV first 16 symbols of string are the same for any password.

 

For example:

Password: kamailio

Encoded: QVFMbEZ4MzZpQ1dPNEp3SsEUkYkN9MYynvOmKYddD6A=

Decoded: çò<õ"×ÅÇR*u¢þn½Ýkamailio

 

Password: kamailio_qwerty123

Encoded: QVFMbEZ4MzZpQ1dPNEp3Sju/bdBKyeVCEgiRrvpBdGs36brwNM+VqNmAzbeQTiy7

Decoded: çò<õ"×ÅÇR*u¢þn½Ýkamailio_qwerty123

 

Best regards,

Arsenijs

 


From: Henning Westerholt <hw@gilawa.com>
Sent: Monday, January 9, 2023 16:00
To: Kamailio (SER) - Users Mailing List <sr-users@lists.kamailio.org>
Cc: Arsenijs Kabihno <a.kabihno@dynatech.lv>
Subject: RE: Kamailio Crypto module and 3rd party openssl

 

Hello,

 

did you tried to actually set a fixed IV in the cfg? Otherwise it will generate a random IV.

 

https://www.kamailio.org/docs/modules/devel/modules/crypto.html#crypto.p.init_vector

 

This was added to provider interoperability to other implementations.

 

Cheers,

 

Henning

 

--

Henning Westerholt – https://skalatan.de/blog/

Kamailio services – https://gilawa.com

 

From: Arsenijs Kabihno <a.kabihno@dynatech.lv>
Sent: Monday, January 9, 2023 1:54 PM
To: sr-users@lists.kamailio.org
Subject: [SR-Users] Kamailio Crypto module and 3rd party openssl

 

Hello,

 

I am trying to make use of crypto module. The scenario is the following:

1.      Encrypt plaintext passwords on kamailio side using crypto_aes_encrypt function of crypto module

2.      Decrypt them outside of kamailio using 3rd party tools, such as PHP openssl_decrypt

 

Crypto module parametrs are the following:

 

modparam("crypto", "salt", "")
modparam("crypto", "key_derivation", 0)

 

If encryption and decription are handled by kamailio, the initial password matches the decrypted string (initial password -> encrypted string -> decrypted string)

For example:

 

sql_query("ds_dburl", "select secret from kamailio_sip_buddies where username='$au'", "secret");

$avp(secret_plain) = $dbr(secret=>[0,0]); //value: 'kamailio'

 

crypto_aes_encrypt("$avp(secret_plain)", "YUZySHVtdlVTYjI0TGJNd3JTeVV0MlRaRWFraFNBRlM=", "$var(encrypted)"); //value: 'qfOqTMoJMgGAherGCqLRRQc4zTlqsEj3MEtcORurFf0='

 

crypto_aes_decrypt("$avp(secret_plain)", "YUZySHVtdlVTYjI0TGJNd3JTeVV0MlRaRWFraFNBRlM=", "$var(decrypted)"); //value: 'kamailio'

 

But in case I try to decrypt the value of $var(encrypted) using PHP openssl_decrypt or online tool like https://www.devglan.com/online-tools/aes-encryption-decryption, I am getting the result 'kamailio' prepended by 16 random bytes, like:

6“¤›¿Ð+IÊ\ñžïZkamailio

or

6�����+I\��Zkamailio

 

I believe this 16 bytes are actually random initialization vector in some encoding.

Possibly kamailio is trimming them from result here:

https://github.com/kamailio/kamailio/blob/master/src/modules/crypto/crypto_mod.c#L511 

 

Moreover, if secret was encrypted using crypto_aes_encrypt and random IV, you can use any IV while decrypting and get 16 different bytes+result

 

Please advice if someone have used crypto module in similar way and what are the possible ways to acheive results consistency