Why is the text not encrypted?

Question

Java

I'm trying to insert an encryption module written in C / C ++ into an android application. It seems to be inserted, everything seems to work, but the application does not work.

native-lib.cpp

#include <jni.h>
#include <string>
#include "gost34-12-15.h"
#include "gost34-13-15.h"
#include "main.cpp"
#include <android/log.h>

std::string jstring2string (JNIEnv * env, jstring jStr);

extern "C" JNIEXPORT jstring JNICALL
Java_com_example_maxim_onlyforc_MainActivity_stringFromJNI(
        JNIEnv *env,
        jobject obj, jstring msg) {

    jstring msg2= crypto(env, msg);
    std::string text = jstring2string(env, msg2) + " проверка";
    return env->NewStringUTF(text.c_str());
}

std::string jstring2string (JNIEnv * env, jstring jStr) {

    if (!jStr)
        return "";

    const jclass stringClass = env->GetObjectClass(jStr);
    const jmethodID getBytes = env->GetMethodID(stringClass, "getBytes", "(Ljava/lang/String;)[B");
    const jbyteArray stringJbytes = (jbyteArray) env->CallObjectMethod(jStr, getBytes, env->NewStringUTF("UTF-8"));

    size_t length = (size_t) env->GetArrayLength(stringJbytes);
    jbyte* pBytes = env->GetByteArrayElements(stringJbytes, NULL);

    std::string ret = std::string((char *)pBytes, length);
    env->ReleaseByteArrayElements(stringJbytes, pBytes, JNI_ABORT);

    env->DeleteLocalRef(stringJbytes);
    env->DeleteLocalRef(stringClass);
    return ret;
}

main.cpp

#include <jni.h>
#include <string>
#include "gost34-12-15.h"
#include "gost34-13-15.h"

unsigned char* jstring2char(JNIEnv * env, jstring);
jbyteArray StringToJByteArray(JNIEnv * env, const std::string &nativeString);

jstring crypto(JNIEnv *env, jstring msg)
{
    // Открытый текст для ГОСТ 34.13-15 \\
    byte* text = jstring2char(env, msg);

    byte key[] = {                                                                      // ключ
                0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff, 0x00, 0x11,
                0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0xfe, 0xdc, 0xba, 0x98, 0x76,
                0x54, 0x32, 0x10, 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef};

    byte IV[] = {0x12, 0x34, 0x56, 0x78, 0x90, 0xab, 0xce, 0xf0, 0xa1, 0xb2,            //синхр. посылка
                 0xc3, 0xd4, 0xe5, 0xf0, 0x01, 0x12, 0x23, 0x34, 0x45, 0x56, 0x67,
                 0x78, 0x89, 0x90, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19};

    init128Gost34_12_15(key);
    encrypt_decrypt_OFB(IV, text, sizeof (text));
    close128Gost34_12_15();
    closeGost34_13_15(IV);
    jstring newText = (*env).NewStringUTF((const char*) text);
    byte* text2 = jstring2char(env, newText);
    return newText;
}

unsigned char* jstring2char (JNIEnv * env, jstring jStr) {

    const jclass stringClass = env->GetObjectClass(jStr);
    const jmethodID getBytes = env->GetMethodID(stringClass, "getBytes", "(Ljava/lang/String;)[B");
    const jbyteArray stringJbytes = (jbyteArray) env->CallObjectMethod(jStr, getBytes, env->NewStringUTF("UTF-8"));

    int len = env->GetArrayLength(stringJbytes);
    unsigned char* buf = new unsigned char[len];
    env->GetByteArrayRegion(stringJbytes, 0, len, reinterpret_cast<jbyte*>(buf));
    return buf;
}

jbyteArray StringToJByteArray(JNIEnv * env, const std::string &nativeString) {
    jbyteArray arr = env->NewByteArray(nativeString.length());
    env->SetByteArrayRegion(arr,0,nativeString.length(),(jbyte*)nativeString.c_str());
    return arr;
}

In the Java file, everything is standard (i.e., the file practically did not change there after creating a project with C / C ++ support). I also don’t throw out plug-in libraries, since the encryption module itself worked on both Qt and Visual Studio. Those. it's not about him.

In total, the ciphertext + the word check should be displayed on the screen. But for some reason it outputs just plain text and I don't understand why at all. What is the problem?