Шифрование/дешифрование - Не удается расшифровать файл - C (СИ)

#include <openssl/rand.h>
#include <openssl/md5.h>
#include <openssl/aes.h>
#include <openssl/evp.h>
#include <openssl/err.h>
#include <stdio.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <sys/mman.h>
#include <libgen.h>
#include <string.h>
#include <errno.h>
#include <inttypes.h>
 
unsigned long get_size_by_fd(int fd)
{
    struct stat statbuf;
    if (fstat(fd, &statbuf) < 0)
    {
        return 1;
    }
    return statbuf.st_size;
}
 
int main(int argc, char **argv)
{
    char filename[1024];
    AES_KEY key = { 0 };
    enum
    {
        none = 0,
        enc = 1,
        dec = 2
    } mode = none;
 
    char password[256] = { 0 };
    uint8_t pswmd5[16];
 
    FILE * fp1 = 0;
    FILE * fp2 = 0;
 
    uint8_t plain_text[1024] = { 0 };
    uint8_t enc_text[1024] = { 0 };
    size_t cbdec;
    size_t cbenc;
 
    int i;
    int status;
    int file_descript;
    unsigned long file_size;
 
    for (i = 1; i < argc; ++i)
    {
        if (strcmp(argv[i], "--help") == 0)
        {
            printf("usage: %s <mode> <filename>\n", basename(argv[0]));
            printf("mode : {-enc|-dec}\n");
            return 0;
        }
 
        if (strcmp(argv[i], "-enc") == 0)
        {
            mode = enc;
        }
        else if (strcmp(argv[i], "-dec") == 0)
        {
            mode = dec;
        }
        else if (*filename)
        {
            strncpy(filename, argv[i], sizeof(filename) - 4);
        }
        else
        {
            printf("invalid argument %s\n", argv[i]);
            return -1;
        }
    }
 
    if (!*filename)
    {
        printf("no filename provided\n");
        return -1;
    }
 
    if (mode == none)
    {
        printf("no mode provided\n");
        return -1;
    }
 
    printf("enter password:");
    if (scanf("%255s", password) != 1)
    {
        printf("input error\n");
        return -1;
    }
 
    if (strlen(password) < 6)
    {
        printf("password bad: too short\n");
        return -1;
    }
 
    MD5(password, (strlen(password) + 1), pswmd5);
 
    status = AES_set_encrypt_key(pswmd5, 16 * 8, &key);
    printf("AES_set_encrypt_key(): status=%d\n", status);
 
    fp1 = fopen(filename, "rb");
    if (!fp1)
    {
        printf("can't open file '%s': %s\n", filename, strerror(errno));
        return -1;
    }
 
    file_descript = open(filename, O_RDONLY);
    file_size = get_size_by_fd(file_descript);
 
    strcat(filename, mode == enc ? ".enc" : ".dec");
    fp2 = fopen(filename, "wb");
    if (!fp2)
    {
        printf("can't open file '%s': %s\n", filename, strerror(errno));
        fclose(fp1);
        return -1;
    }
 
    if (mode == enc)
    {
        while ((cbenc = fread(plain_text, 1, sizeof(enc_text) - 16, fp1)) > 0)
        {
            if (cbenc % 16 != 0)
            {
                cbenc = (cbenc / 16 + 1) * 16;
            }
 
            AES_encrypt(plain_text, enc_text, &key);
 
            if (fwrite(enc_text, 1, cbenc, fp2) == 0)
            {
                fprintf(stderr, "can't write to file '%s': %d (%s)", filename,
                        errno, strerror(errno));
                break;
            }
        }
 
    }
    else
    {
        while ((cbdec = fread(enc_text, 1, sizeof(enc_text), fp1)) > 0)
        {
            if (cbdec % 16 != 0)
            {
                cbdec = (cbdec / 16 + 1) * 16;
            }
 
            AES_decrypt(enc_text, plain_text, &key);
 
            if (fwrite(plain_text, 1, cbdec, fp2) == 0)
            {
                fprintf(stderr, "can't write to file '%s': %d (%s)", filename,
                        errno, strerror(errno));
                break;
            }
        }
    }
 
    fclose(fp2);
    fclose(fp1);
    return 0;
}