How to solve undefined reference to `AES_ctr128_encrypt' - c

Question

Hello I was studying aes 128 encryption with this link https://www.gurutechnologies.net/blog/aes-ctr-encryption-in-c/.
But to run the example main.c
Compiled as follows
gcc main.c -lm -lcrypto -lssl -o mai.c
Then I get the following error:
main.c: In function ‘fencrypt’:
main.c:83:3: warning: implicit declaration of function ‘AES_ctr128_encrypt’; did you mean ‘AES_cfb128_encrypt’? [-Wimplicit-function-declaration]
AES_ctr128_encrypt(indata, outdata, bytes_read, &key, state.ivec, state.ecount, &state.num);
^~~~~~~~~~~~~~~~~~
AES_cfb128_encrypt
/tmp/cc1Gq6eV.o: In function `fencrypt':
main.c:(.text+0x253): undefined reference to `AES_ctr128_encrypt'
/tmp/cc1Gq6eV.o: In function `fdecrypt':
main.c:(.text+0x449): undefined reference to `AES_ctr128_encrypt'
collect2: error: ld returned 1 exit status
To fix this I go into the directory where openssl is located, and in the aes.h header file
I tried to find the AES_ctr128_encrypt function, but it did not
So I updated the openssl and confirmed that there is a AES_ctr128_encrypt function in aes.h and tried to recompile it, but nothing changed. I will leave a question because I could not find a solution anymore.
This is the code for AES_ctr128_encrypt
void fencrypt(char* read, char* write, const unsigned char* enc_key)
{
if(!RAND_bytes(iv, AES_BLOCK_SIZE))
{
fprintf(stderr, "Could not create random bytes.");
exit(1);
}
readFile = fopen(read,"rb"); // The b is required in windows.
writeFile = fopen(write,"wb");
if(readFile==NULL)
{
fprintf(stderr, "Read file is null.");
exit(1);
}
if(writeFile==NULL)
{
fprintf(stderr, "Write file is null.");
exit(1);
}
fwrite(iv, 1, 8, writeFile); // IV bytes 1 - 8
fwrite("\0\0\0\0\0\0\0\0", 1, 8, writeFile); // Fill the last 4 with null bytes 9 - 16
//Initializing the encryption KEY
if (AES_set_encrypt_key(enc_key, 128, &key) < 0)
{
fprintf(stderr, "Could not set encryption key.");
exit(1);
}
init_ctr(&state, iv); //Counter call
//Encrypting Blocks of 16 bytes and writing the output.txt with ciphertext
while(1)
{
bytes_read = fread(indata, 1, AES_BLOCK_SIZE, readFile);
AES_ctr128_encrypt(indata, outdata, bytes_read, &key, state.ivec, state.ecount, &state.num);
bytes_written = fwrite(outdata, 1, bytes_read, writeFile);
if (bytes_read < AES_BLOCK_SIZE)
{
break;
}
}
fclose(writeFile);
fclose(readFile);
}
void fdecrypt(char* read, char* write, const unsigned char* enc_key)
{
readFile=fopen(read,"rb"); // The b is required in windows.
writeFile=fopen(write,"wb");
if(readFile==NULL)
{
fprintf(stderr,"Read file is null.");
exit(1);
}
if(writeFile==NULL)
{
fprintf(stderr, "Write file is null.");
exit(1);
}
fread(iv, 1, AES_BLOCK_SIZE, readFile);
//Initializing the encryption KEY
if (AES_set_encrypt_key(enc_key, 128, &key) < 0)
{
fprintf(stderr, "Could not set decryption key.");
exit(1);
}
init_ctr(&state, iv);//Counter call
//Encrypting Blocks of 16 bytes and writing the output.txt with ciphertext
while(1)
{
bytes_read = fread(indata, 1, AES_BLOCK_SIZE, readFile);
//printf("%i\n", state.num);
AES_ctr128_encrypt(indata, outdata, bytes_read, &key, state.ivec, state.ecount, &state.num);
bytes_written = fwrite(outdata, 1, bytes_read, writeFile);
if (bytes_read < AES_BLOCK_SIZE)
{
break;
}
}
fclose(writeFile);
fclose(readFile);
}
Thank you in advance.

Answer 1

Assuming you are using openssl 1.1.0, see What is exact alternate API instead of AES_ctr128_encrypt from openssl 1.1.0?
You can use CRYPTO_ctr128_encrypt instead of AES_ctr128_encrypt.