Unsigned char to char* and int in C?

Question

Working on some encryption that requires unsigned char's in the functions, but want to convert to a char for use after it's been decrypted. So, I have:

unsigned char plaintext[16];
char *plainchar;
int plainint;

... Code now populates plaintext with data that happens to all be plain text

Now at this point, let's say plaintext is actually a data string of "0123456789". How can I get the value of plaintext into plainchar as "012456789", and at the same time plainint as 123456789?

-- Edit --

Doing this when plaintext is equal to "AAAAAAAAAA105450":

unsigned char plaintext[16];
char *plainchar;
int plainint;

... Code now populates plaintext with data that happens to all be plain text

plainchar = (char*)plaintext;

Makes plainchar equal to "AAAAAAAAAA105450╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠╠┤∙7" with a sizeof = 51. The encryption code is the rijndael example code, so it should be working fine.

Thanks, Ben

Answer 1

Your plain text string is not terminated. All strings must have an extra character that tells the end of the string. This character is '\0'.

Declare the plaintext variable as

unsigned char plaintext[17];

and after you are done with the decryption add this

plaintext[last_pos] = '\0';

Change last_pos to the last position of the decrypted text, default to 16 (last index of the array).

Answer 2

I think its simply

plainchar = (char*)plaintext;
sscanf( plainchar, "%d", &plainint );

Answer 3

for unsigned char to char*

plainchar = (char*)plaintext;

for unsigned to int

sscanf( plainchar, "%d", &plainint );