Extra Systems

CYPHERNET

key loading procedure load_rsa_keys

RSA encryption keys are stored on disk in packed form, and after reading (for further use) are unpacked element by element using the unpack_value procedure.

typedef struct rsa_key_item
{
	unsigned char exponent[VALUE_LENTH];
	unsigned char modulus[VALUE_LENTH];
} RSAKEYITEM;

typedef struct rsa_key_packed_item
{
	unsigned char exponent[PACKED_VALUE_LENTH];
	unsigned char modulus[PACKED_VALUE_LENTH];
} RSAKEYPACKEDITEM;

RSAKEYITEM encrypt_rsa_key, decrypt_rsa_key;

int load_rsa_keys(char *encrypt_rsa_key_file, char *decrypt_rsa_key_file)
{
	int file_handle;
	RSAKEYPACKEDITEM packed_key_item;
	if((file_handle = open(encrypt_rsa_key_file, O_RDONLY)) == -1) return 0;
	read(file_handle, &packed_key_item, sizeof(packed_key_item));
	close(file_handle);
	unpack_value(packed_key_item.exponent, encrypt_rsa_key.exponent);
	unpack_value(packed_key_item.modulus, encrypt_rsa_key.modulus);
	if((file_handle = open(decrypt_rsa_key_file, O_RDONLY)) == -1) return 0;
	read(file_handle, &packed_key_item, sizeof(packed_key_item));
	close(file_handle);
	unpack_value(packed_key_item.exponent, decrypt_rsa_key.exponent);
	unpack_value(packed_key_item.modulus, decrypt_rsa_key.modulus);
	return 1;
}

The parameters of this procedure are the names of the public (communication partner) and private (own) RSA key files.

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