The public key file itself contains modulus and public key. Take 1024 bit public key as an example, use UE32 or winhex software to open the public key file. //The first four bytes (0-3) are the length of the public key: 0000080 is 128 bytes//and the following 128 bytes (4- 13 1) is the n value of the public key, so it is directly put in the program//the following four.