Tech Blog of Edward – Page 2 – Remember the steps, do be do be do

[libressl] Generate RSA key

1 June, 2018

In the latest version of libressl, RSA_generate_key is deprecated, RSA_generate_key_ex should be implemented instead. Implementation (updated) Source file (test.c)

#include <openssl/rsa.h>
#include <openssl/pem.h>

int main(){
	const int kBits = 2048;
	unsigned long e = RSA_F4;
	int keylen;
	char *pem_key;
	
	// BIGNUM PART
	BIGNUM* bignum = BN_new();
	if(BN_set_word(bignum, e))
		printf("[Debug] BIGNUM allocated!\n");
	else
		printf("[Debug] BIGNUM NOT allocated!\n");

	// RSA PART
	RSA *rsa = RSA_new();
	if(RSA_generate_key_ex(rsa, 2048, bignum, NULL))
		printf("[Debug] RSA allocated!\n");
	else
		printf("[Debug] RSA NOT allocated!\n");

	// BIO PART
	BIO *bio = BIO_new(BIO_s_mem());
	PEM_write_bio_RSAPrivateKey(bio, rsa, NULL, NULL, 0, NULL, NULL);

	keylen = BIO_pending(bio);
	pem_key = calloc(keylen+1, 1); /* Null-terminate */
	BIO_read(bio, pem_key, keylen);

	// OUTPUT
	printf("%s", pem_key);

	// FREE THE MEMORY
	BIO_free_all(bio);
	RSA_free(rsa);
	BN_free(bignum);
	free(pem_key);
	return 0;
}

#include <openssl/rsa.h>

#include <openssl/pem.h>

int main(){

const int kBits = 2048;

unsigned long e = RSA_F4;

int keylen;

char *pem_key;

// BIGNUM PART

BIGNUM* bignum = BN_new();

if(BN_set_word(bignum, e))

printf("[Debug] BIGNUM allocated!\n");

else

printf("[Debug] BIGNUM NOT allocated!\n");

// RSA PART

RSA *rsa = RSA_new();

if(RSA_generate_key_ex(rsa, 2048, bignum, NULL))

printf("[Debug] RSA allocated!\n");

else

printf("[Debug] RSA NOT allocated!\n");

// BIO PART

BIO *bio = BIO_new(BIO_s_mem());

PEM_write_bio_RSAPrivateKey(bio, rsa, NULL, NULL, 0, NULL, NULL);

keylen = BIO_pending(bio);

pem_key = calloc(keylen+1, 1); /* Null-terminate */

BIO_read(bio, pem_key, keylen);

// OUTPUT

printf("%s", pem_key);

// FREE THE MEMORY

BIO_free_all(bio);

RSA_free(rsa);

BN_free(bignum);

free(pem_key);

return 0;

}

…

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C, Linux

[libressl] Setup

28 May, 2018

SETUP Install the dependencies first

sudo apt-get update
sudo apt-get install automake autoconf git libtool perl

1 2	sudo apt-get update sudo apt-get install automake autoconf git libtool perl

Clone the repository from Github

git clone https://github.com/libressl-portable/portable.git libressl

1	git clone https://github.com/libressl-portable/portable.git libressl

Prepare…

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Algorithms, C++

Breadth first search

27 May, 2018

Steps: Add root to queue If left child not null, add it to queue If…

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C, C++, Language

CMake command

26 May, 2018

Set variable Basic usage of SET

SET(GCC_PATH    /usr/bin/gcc)
# SET variable "GCC_PATH" to "/usr/bin/gcc"

1 2	SET(GCC_PATH /usr/bin/gcc) # SET variable "GCC_PATH" to "/usr/bin/gcc"

To include existing variables in the SET…

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C++

Google C++ style guide

10 May, 2018

Filenames should be all lowercase with underscores (_) or dashes (-) hello_world.cc All types like classes,…

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C++

C++ 11

10 May, 2018

Auto type

// BEFORE
for(vector<Person>::iterator it = personVec.begin(); it != personVec.end(); it++)
{...}

// IN C++ 11
for(auto it = personVec.begin(); it != personVec.end(); it++)
{...}

// BEFORE

for(vector<Person>::iterator it = personVec.begin(); it != personVec.end(); it++)

{...}

// IN C++ 11

for(auto it = personVec.begin(); it != personVec.end(); it++)

{...}

Auto type + Ranged-based for loop

// BEFORE
int i = 0;
for(vector<Person>::iterator it = personVec.begin(); it != personVec.end(); it++, i++){
    personVec[i].printName();
}

// IN C++ 11 *Work only for container with begin() and end()
//     Read only access
for(auto person : personVec){
     person.printName();
}

//     To write
for(auto& person : personVec){
     person.name = "Overwritten";
}

// BEFORE

int i = 0;

for(vector<Person>::iterator it = personVec.begin(); it != personVec.end(); it++, i++){

personVec[i].printName();

}

// IN C++ 11 *Work only for container with begin() and end()

// Read only access

for(auto person : personVec){

person.printName();

}

// To write

for(auto& person : personVec){

person.name = "Overwritten";

}

Initializer list

// BEFORE
personVec.push_back(person1);
personVec.push_back(person2);
personVec.push_back(person3);

// IN C++ 11
personVec = { person1, person2, person3 }

// BEFORE

personVec.push_back(person1);

personVec.push_back(person2);

personVec.push_back(person3);

// IN C++ 11

personVec = { person1, person2, person3 }

…

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Gatekeeper

[Method]alloc_and_fill_notify_pkt

2 May, 2018

Depending on the ethertype, by using rte_pktmbuf_append, the following component will be packed into the…

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C, Gatekeeper, Linux

Gatekeeper [Network setup]

18 February, 2018

DPDK(network setup) Add two virtual network interfaces in settings in Virtual Box

"Network > Adapter x"
Attached to : Bridged Adapter

"Advanced"
Adapter Type : Intel PRO/1000 MT Server (82545EM)

"Network > Adapter x"

Attached to : Bridged Adapter

"Advanced"

Adapter Type : Intel PRO/1000 MT Server (82545EM)

Check if…

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Gatekeeper setup (DPDK)

13 February, 2018

Background The system has been built using these four Linux distributions.

Fedora 27
Kali Linux
Arch Linux
Kbuntu (KDE version of Ubuntu)

Fedora 27

Kali Linux

Arch Linux

Kbuntu (KDE version of Ubuntu)

Thank to…

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Fix, Windows

Recover corrupted USB from format of other OS to windows

7 February, 2018

Call diskpart utility In Windows cmd.exe

diskpart

diskpart

To see the list of disk attached…

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