https://github.com/z1skgr/rsa-crypto
Cryptographic algorithm using openssl
https://github.com/z1skgr/rsa-crypto
bignum cryptography encryption-decryption hash openssl public-key rsa
Last synced: 7 months ago
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Cryptographic algorithm using openssl
- Host: GitHub
- URL: https://github.com/z1skgr/rsa-crypto
- Owner: z1skgr
- Created: 2022-03-12T13:37:06.000Z (over 3 years ago)
- Default Branch: main
- Last Pushed: 2024-11-27T12:16:07.000Z (11 months ago)
- Last Synced: 2025-01-23T09:11:28.756Z (9 months ago)
- Topics: bignum, cryptography, encryption-decryption, hash, openssl, public-key, rsa
- Language: C
- Homepage:
- Size: 563 KB
- Stars: 2
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# rsa/crypto
> Cryptographic algorithm using public key cryptosystem :tada:
## Table of contents
* [General Info](#general-information)
* [Setup](#setup)
* [How to run](#how-to-run)
* [Acknowledgements](#acknowledgments)
## General Information
__RSA__ is an asymmetric cryptographic algorithm where each user has two keys
* private
* public
It uses data from the theory of numbers and in combination with the particularly large keys achieves encryption in
a balance arithmetic that makes decryption by factorization impossible.
### bn_act_1 & 2.c
1. Create a private key[^4]
2. Message encryption
| | Description |
| ------------- | ------------- |
| p | Prime |
| q | Prime |
| e | number |
| n | p * q |
| e,n | Public key |
| d | Private key |
Calculations
$public_{key} = (e,n)$
$p = 953AAB9B3F23ED593FBDC690CA10E703$
$q = C34EFC7C4C2369164E953553CDF94945$
$e = 0D88C3$
$n = p * q$
$M = "message"$
#### Act
* Calculate private key d
* Name surname encryption
### bn_act_3 & 4_1.c
1. Message decryption
2. Message signing
Calculations
$d = 74D806F9F3A62BAE331FFE3F0A68AFE35B3D2E4794148AACBC26AA381CD7D30D$
$e = 010001 (this hex value equals to decimal 65537) $
$n = DCBFFE3E51F62E09CE7032E2677A78946A849DC4CDDE3A4D0CB81629242FB1A5$
$M = "message"$
$M` = "messag"$
#### Act
* Decrypt message using private and public key
* Message signing to two different texts
### bn_act_4-2.c
1. Signature Verification
Calculations
$public_{key} (e,n)$
$S = 643D6F34902D9C7EC90CB0B2BCA36C47FA37165C0005CAB026C0542CBDB6802F$
$e = 010001 (this hex value equals to decimal 65537) $
$n = AE1CD4DC432798D933779FBD46C6E1247F0CF1233595113AA51B450F18116115$
$M = "Launch a missile"$
#### Act
* Signing verification
* Signing verification with modified S (last bit 2F->3F)
## Setup
Large numbers **bn[^1]** (multiprecision integer arithmetics) library provided by the **openssl [^2]**
For more information, you can check [bn](https://www.openssl.org/docs/man1.0.2/man3/bn.html).
Check the virtual Ubuntu SEED machine 16.04.
1. Download SEEDUbuntu-v 16.04 from site
```
https://seedsecuritylabs.org/lab_env.html
```
2. Download and install VM engine from site
```
https://www.virtualbox.org/wiki/Downloads
```
3. Build a new VM os importing SEEDUbuntu
* Select OS Type Linux [^3] version Ubuntu
4. PRE-build VM hard disk from SEED file
* From the unzipped folder, select ```xxxx.vmdk``` where xxx is the SEED_name_version
5. Setting->General->Advanced
- [x] Shared Clipboard : Bidirectional
- [x] Drag'n'Drop : Bidirectional
- [x] Controller : VBoxVGA
- [x] Processor : 1+
6. Open terminal
```
$ sudo apt update
$ sudo apt install build-essential checkinstall zlib1g-dev -y
$ cd /usr/local/src/
$ wget https://www.openssl.org/source/openssl-1.0.2o.tar.gz
$ tar -xf openssl-1.0.2o.tar.gz
$ cd openssl-1.0.2o
$ ./config --prefix=/usr/local/ssl --openssldir=/usr/local/ssl shared zlib
$ make
$ make test
$ make install
```
7. Configure libraries
```
$ cd /etc/ld.so.conf.d/
$ vim openssl-1.0.2o.conf
```
8. Paste
```
$ /usr/local/ssl/lib
```
9. Reload link
```
$ sudo ldconfig -v
```
You can edit with atom or any other editor
OpenSSL is installed in the `'/usr/local/ssl'` directory.
## How to run
Any `.c` file can be executed as
```
gcc XXXXX -o XXXXXX.c -lcrypto
```
where `XXXXX` filename
## Acknowledgments
* Assignment for cryptography
[^1]: BIGNUM can represent every great number, see https://www.openssl.org/docs/man1.0.2/man3/bn.html
[^2]: https://www.openssl.org
[^3]: Make sure install version ubuntu x32 architecture compatible with SEEDUbuntu.
[^4]: For simplicity, we use numbers 128 bits. Must be 512.