How to encrypt variable size of data by using AES (CBC) 128 Algorithm

I want encrypt 4 byte of data, but AES takes 16 byte of data as input and gives 16 bytes as output,
So How to overcome this problem, If some have source code please share

Thanks

To encrypt 4 byte of data we need to add 12 more bytes and make a block of 16 bytes, its take more data length to transfer via wireless, So How to send Encrypted data with Real data length

On encryption, append 12 bytes of random junk.
On decryption, ignore the last 12 bytes.

If length is not fixed, then
[1-bit junk][7-bit bit-length][n-bits of data][128-8-n junk bits to fill to 128]

Cipher block chaining (CBC mode) requires that the plaintext be a mulitple of the block size. If it is not, you'll need to pad it out to a multiple of the block size.

Cipher-feedback mode (CFB mode) exists primarily to avoid this -- as it uses the block cipher as a way of generating key bits to XOR with the the plaintext to encrypt it, it can be used with any bit length and padding is not needed. With CFB mode, however, it is critical to not reuse IVs, as that will directly leak the first block of the plaintext. In CBC mode, reusing IVs is still bad (will leak info about correlated inputs), but arguably not as bad.