Skip to main content

Digital Signatures

The only real reason this is ever a confusing topic is because instructors spend a lot of time drilling into student’s heads that the public key is for encryption and that the private key is for decryption. In general, this is a true statement (and I’m willing to bet you’ll see it on your exam that way). However, remember that the keys are created in pairs—what one key does, the other undoes. If you encrypt something with the public key, the private key is the only one that can decrypt it. But that works in reverse, too—if you encrypt something with your private key, your public key is the only thing that can decrypt it. Keeping this in mind, the digital signature is an easy thing to understand. A digital
signature is nothing more than an algorithmic output that is designed to ensure the authenticity (and integrity) of the sender—basically a hash algorithm. The way it works is simple:
1. Bob creates a text message to send to Joe.
2. Bob runs his message through a hash and generates an outcome.
3. Bob then encrypts the outcome with his private key and sends the message, along with the encrypted hash, to Joe.
4. Joe receives the message and attempts to decrypt the hash with Bob’s public key. If it works, he knows the message came from Bob.
When it comes to PKI, asymmetric encryption, digital certificates, and digital signatures, remembering a few important facts will solve a lot of headaches for you. Keys are generated in pairs, and what one does, the other undoes. In general, the public key (shared with everyone) is used for encryption, and the private key (kept only by the owner) is used for decryption. Although the private key is created to decrypt messages sent to the owner, it is also used to prove authenticity through the digital signature (encrypting with the private key allows recipients to decrypt with the readily available public key). Key generation, distribution, and revocation is best handled within a framework, often referred to as PKI. PKI also allows for the creation and dissemination of digital certificates, which are used to prove the identity of an entity on the network and follow a standard (X.509).

Comments

Post a Comment

thank you for visiting :)

Popular posts from this blog

Special Permissions in linux

The setuid permission on an executable file means that the command will run as the user owning the file, not as the user that ran the command. One example is the passwd command: [student@desktopX ~]$ ls -l /usr/bin/passwd -rw s r-xr-x. 1 root root 35504 Jul 16 2010 /usr/bin/passwd In a long listing, you can spot the setuid permissions by a lowercase s where you would normally expect the x (owner execute permissions) to be. If the owner does not have execute permissions, this will be replaced by an uppercase S . The special permission setgid on a directory means that files created in the directory will inherit their group ownership from the directory, rather than inheriting it from the creating user. This is commonly used on group collaborative directories to automatically change a file from the default private group to the shared group, or if files in a directory should be...
Post a Comment
Read more

The Seven-Step Model of Migration

Irrespective of the migration approach adopted, the Seven-step Model of Cloud Migration creates a more rational point of view towards the migration process and offers the ability to imbibe several best practices throughout the journey Step 1: Assess Cloud migration assessments are conducted to understand the complexities in the migration process at the code, design and architectural levels. The investment and the recurring costs are also evaluated along with gauging the tools, test cases, functionalities and other features related to the configuration. Step 2: Isolate The applications to be migrated to the cloud from the internal data center are freed of dependencies pertaining to the environment and the existing system. This step cuts a clearer picture about the complexity of the migration process. Step 3: Map Most organisations hold a detailed mapping of their environment with all the systems and applications. This information can be used to distinguish between the ...
Post a Comment
Read more

Linux File System Permissions

Access to files by users are controlled by file permissions . The Linux file permissions system is simple but flexible, which makes it easy to understand and apply, yet able to handle most normal permission cases easily. Files have just three categories of user to which permissions apply. The file is owned by a user , normally the one who created the file. The file is also owned by a single group , usually the primary group of the user who created the file, but this can be changed. Different permissions can be set for the owning user, the owning group, and for all other users on the system that are not the user or a member of the owning group. The most specific permissions apply. So, user permissions override group permissions, which override other permissions. In the graphic that follows, joshua is a member of the groups joshua and web, while allison is a member of allison, wheel, and web. Whe...
Post a Comment
Read more

tag