System – Page 3 – POFTUT

Category: System


How To Recover Data with ddrescue Command?

ddrescue is a GNU provided data recovery tool.It can copy and recover file, directory or whole hard drive. The best part of the ddrescue is it can prevent or solve read errors. Install For Ubuntu, Debian, Kali and Mint We can install ddrescue tool for deb based distributions like below. ddrescue command is provided with package name gddrescue.

List Hard Drives Before rescuing or copying files and directories we...


How To Delete File and Folders Completely and Securely with sdelete in Windows?

User PC and Servers process a lot of data where some of them are secret. This data may be deleted with conventional ways but this may not enough. Because file systems generally removes file metadata but continue to hold real data. Microsoft sysinternals provides sdelete or secure delete tool which can delete file data really. More information about sysinternals can be get below. What Is Windows Sysinternal? Download As stated...


How To Read RSA, X509, PKCS12 Certificates with OpenSSL?

OpenSSL provides read different type of certificate and encoding formats. OpenSSL supports certificate formats like RSA, X509, PCKS12 etc. We will look how to read these certificate formats with OpenSSL. Read RSA Private Key RSA is popular format use to create asymmetric key pairs those named public and private key. We can use rsa verb to read RSA private key with the following command.

We can see that the first...


How To Create Self Signed Root Certificate with OpenSSL

OpenSSL provides cryptographic libraries and features. We can use OpenSSL from reading DER files to generate random numbers. But one of the most used feature is creating a Self Signed Certificate. , Self Signed Certificate X509 is the certificate standard used in internet and corporate today. X509 certificates are designed to create a tree like trust hierarchy between X509 certificates. For example Google is a trusted entity and is another...


How To Convert DER To PEM and PEM to DER Certificate Format with OpenSSL?

DER and PEM are formats used in X509 and other certificates to store Public, Private Keys and other related information. OpenSSL provides a lot of features for manipulating PEM and DER certificates. We can use OpenSSL to convert DER to PEM format and vice versa. Convert DER Format To PEM Format For RSA Key We may have an RSA Key in DER format and we want to convert it into...


How To Determine and Print OpenSSL Version?

OpenSSL is very long running project which have passed a lot of versions. Newer versions provides more features, bug fixes and security patches. For example in year 2014 a serious security hole Heart Bleed discovered in OpenSSL versions and affected OpenSSL libraries are defined as versions.Following versions was vulnerable to Hear Bleed. OpenSSL 1.0.1 trough 1.0.1f inclusive OpenSSL 1.0.1g is not vulnerable So version is important part of the OpenSSL...


How To Generate Certificate Signing Request (CSR) with OpenSSL?

OpenSSL provides different features about security and certificates. Public and Private Key cryptography also supported by OpenSSL. Websites, Firewalls and other applications uses Certificates in order to encrypt their network traffic or authenticate each other. In this tutorial we will look how to create Certificate Signing Request. Generate RSA Key Now we assume we do not have any Public and Private Key pair. If we have Public and Private key...


How To Generate Random Numbers and Password with OpenSSL Rand

OpenSSL is great library and tool set used in security related work. While talking security we can not deny that passwords and random numbers are important subjects. In this tutorial we will learn how to generate random numbers and passwords with OpenSSL. Generate Base64 Random Numbers Base64 is an encoding format used in applications and different systems which can be transferred and used without problem. Base64 do not provides control...


How To Use OpenSSL s_client To Check and Verify SSL/TLS Of HTTPS Webserver?

OpenSSL provides different features and tools for SSL/TLS related operations. s_lient is a tool used to connect, check, list HTTPS, TLS/SSL related information. Simply we can check remote TLS/SSL connection with s_client . In this tutorials we will look different use cases of s_client . Check TLS/SSL Of Website The basic and most popular use case for s_client is just connecting remote TLS/SSL website. We will provide the web site with the HTTPS port...


OpenSSL Shell Commands Tutorial with Examples

OpenSSL is free security protocols and implementation library provided by Free Software community. OpenSSL libraries are used by a lot of enterprises in their systems and products. OpenSSL libraries and algorithms can be used with openssl command. In this tutorial we will look different use cases for openssl command. Private Key Private keys should kept secret. Private keys generally used to decrypt data. Public Key Public keys are provided every one and...

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