PGP Encryption: How It Works and How You Can Get Started
Dec 21, †Ј PGP shares some features with other encryption systems you may have heard of, like Kerberos encryption (which is used to authenticate network users) and SSL encryption (which is used to secure websites). At a basic level, PGP encryption uses a combination of two forms of encryption: symmetric key encryption, and public-key encryption. Aug 08, †Ј As you can see, PGP uses a combination of symmetric key encryption (i.e., a single-use session key encrypts and decrypts the message) and public key encryption (i.e., the keys unique to the recipient encrypt and decrypt the session key).
When you send an encrypted email with ProtonMail, your message encrgption automatically protected with PGP encryption. What is PGP?
This article explains the tech behind our security promise. In fact, PGP is the most widely used email encryption system in the world. When you send messages using PGP encryption, no one can intercept and read your message in transit. PGP has been thoroughly field tested over its decades of use, its few vulnerabilities are well understood, and it has broad compatibility with other encryption clients. For these reasons, we use PGP as the backbone of our security architecture.
This article is part of a gpp explaining some of the tech behind ProtonMail. We have already covered end-to-end encryption and zero-access encryption.
PGP is a cryptographic method that lets people communicate privately online. When you dies a message using PGP, the message is converted into unreadable ciphertext on your device before it passes over the Internet.
Only the recipient has the key to convert the text back into the readable message on their device. PGP also authenticates the identity of the sender and verifies that the message was not tampered with in transit.
Before PGP, your Internet provider, your email provider, hackers, or the government could theoretically read your messages. PGP was developed in the s to allow email and other types of messages to be exchanged privately.
Historically, PGP has been difficult to use, requiring additional software applications on top of your email provider or client. You also have to manually generate encryption keys and exchange them with your contacts. When you compose an email to uze ProtonMail user and click send, the message encryption and signature are applied automatically. ProtonMail makes PGP encryption, easy, convenient, and accessible to everyone.
As you can see, PGP uses a combination of symmetric key encryption i. The first thing PGP does is generate a random session key.
This key is an enormous number that is used to encrypt and decrypt the contents of how to get a master key message. Only someone who knows the session key can read the message, and it is much too large what encryption does pgp use guess. The session key is also never used again for how to replace vista with windows xp messages.
The public key is unique to each person and meant to be shared. It is tied to you, and anyone can use it to send you an encrypted message. In PGP, when the recipient receives an encrypted message, they decrypt the session key using their private key. The plaintext session key then decrypts the message. You might wonder why PGP takes the extra step of encrypting the message and the session key. This is because public-key cryptography is much slower than symmetric cryptography, especially for large messages.
It would take too much time and computing power to encrypt and decrypt large emails or files directly using the public key. But symmetric cryptography without public-key cryptography encryptioon less convenient because you would need to somehow share the what is a proxy solicitation key with the recipient. To do so in plaintext would not be secure, and to do so via another encrypted channel or in person would be impractical.
Therefore, PGP combines the efficiency of symmetric encryption and the convenience of public key encryption. There are two other aspects of PGP to note. The first is the digital signature. A digital signature proves encryptioon the recipient that an attacker has not manipulated the message or the sender. If either the private key or the message is altered, the digital enfryption is invalid.
After all, the server could easily give a bogus public key to the sender. To solve this problem, we introduced Address Verificationwhich allows you to share your public key and digitally sign the public keys of others that you have personally verified. These trusted public keys are then securely stored in your encrypted contacts.
It will automatically verify the public key of each recipient you send email towithout requiring any manual action. PGP is a battle-tested standardand we can be virtually certain that even intelligence agencies like the NSA cannot break its encryption. While there have been security bugs with certain implementations of PGP, such as the infamous Efail vulnerabilityPGP itself is very secure. ProtonMail has not been affected by any known vulnerabilities. Ejcryption most other information security systems, odes biggest weakness is the user.
Often the simplest and most effective attacks are the least high-tech, as this comic illustrates. Phishing remains the most common kind of cyberattack, and PGP cannot encdyption you if your device or accounts are compromised. Check out these email safety tips. While there are programs for Thunderbird, Encrypfion, and Apple Mail that enable PGP encryption, these are not practical solutions for everyday emails.
ProtonMail solves this problem by making PGP encryption automatic and built-in for all emails sent between ProtonMail accounts. You can also easily encrypt emails to non-ProtonMail users. Anyone can create a free ProtonMail account in a minute or two and immediately whaf sending PGP emails. As supercomputers get faster and new encryption standards gain popularity, ProtonMail will continue to adapt to new cyber threats and the needs of our users.
Our cryptographers are working hard on doe projects, like Key Transparency and Des Code Transparency. We also recently upgraded our users to elliptic curve cryptographywhich maximizes security and efficiency. You can get a free secure email account from ProtonMail here. We also provide a free VPN service to protect your privacy. If you would like to support our development efforts, you can upgrade to a paid plan or donate. Thank you how to calculate acreage from area your support.
Ben Wolford is a writer at Proton. A journalist for many years, Ben joined Proton to help lead the fight for data privacy. Leave this field empty.
Hi Fabio! Key Transparency and ProtonDrive are both top development priorities for us right now. Is there a way to import your external key to Protonmail so that it automatically sends encrypted email without your sender making an effort to import their key?
When I send an email to someone on Protonmail, I make the effort to first download their key from your public key server thanks for itso that I send them an encrypted email from the beginning. I explicitly sent them my key telling them what to do with it, but they continued to ignore my instruction. They just seem to not care about PGP and email privacy.
Should I protect my privacy by not sending email to Protonmail? Thanks for the comment! Good article but I think you need to write one for an audience that has no idea about encryption. When I explain encryption to someone I typically start by the differences between symmetric and asymmetric encryption. This alone takes a bit of time to get your head around if you never heard it. This is a good suggestion, Basti!
Thank you. I think this can be misinterpreted by regular users if we read it to quickly, it is important to not give a feeling of privacy to regular user when there is none. For any regular user a would put a bold two lines summary that is honest and clearly indicates what they should know :. Thanks, Nano, this is absolutely correct.
General: contact protonmail. For support inquiries, please visit protonmail. Return to protonmail. Toggle navigation. How does PGP work? Digital signatures There are two other aspects of PGP to note. How secure is PGP? Final thoughts As supercomputers get faster and new encryption standards gain popularity, ProtonMail will continue to adapt to new cyber threats and the needs of our users. Article updated Aug. Get a Free Encrypted Email Account.
Ben Wolford Ben Wolford how to paint glitter on walls a writer at Proton. We believe a key step toward that is having well-maintained, robust, and secure openЕ. What is zero-access encryption and why it is important for security May 23, in Security Most of us would not give our private, personal information to strangers and then trust them not to leak it.
What is end-to-end encryption and how does it work? March 7, in Encryption End-to-end encryption is the most secure way to what is a hunger games server privately and securely online. By encrypting messages at both ends of a conversation, end-to-end encryption prevents anyone in theЕ. Leave a Reply Cancel reply Your email address will not be published. FabioAugust 9, at AM. Ben WolfordAugust 19, at AM.
BastiAugust 14, at AM.
PGP Encryption Uses
Apr 23, †Ј PGP is the gold standard for encrypted communication and has been used by everyone from nuclear activists to criminals since its invention in While the execution is complex, the concept is simple: you can encrypt text, making it unreadable to anyone who doesnТt have the key to decode it. How does it work? УPGPФ stands for УPretty Good PrivacyФ; УGPGФ stands for УGnu Privacy Guard.Ф It was the original freeware copyrighted program; GPG is the re-write of PGP. The PGP uses the RSA algorithm and the IDEA encryption algorithm. GPG uses the NIST AES, Advanced Encryption Standard. PGP transmits the signature and the plaintext together. Upon receipt of the message, the recipient uses PGP to recompute the digest, thus verifying the signature. PGP can encrypt the plaintext or not; signing plaintext is useful if some of the recipients are not interested in or capable of verifying the signature.
PGP P retty G ood P rivacy encryption has become a mainstay of internet privacy and security for one main reason: it allows you to send a coded message to someone without having to share the code beforehand. If you send the code alongside the coded message, then anyone that intercepts the message can access the contents just as easily as the recipient. Contents [ hide ]. It also allows recipients to verify whether a message is authentic or if it has been tampered with.
It does this by using something called digital signatures , which we will cover later in the article. On top of this, PGP can be used to encrypt other things besides email. You can use it to encrypt your hard drive, instant messages, files and more. When your email leaves your account and gets sent across the internet, it transits through networks that are beyond your control.
Your personal messages can be snatched by hackers who might use it to commit identity fraud, while important government messages can fall into the hands of spies.
These dangers are part of why PGP was inventedЧto bring some semblance of privacy and security to the Wild West that is email communication. It stands for Pretty Good Privacy , which may not inspire a whole lot of confidence for something that people rely on to keep their communications secure.
This means that as long as it is used properly, you can be confident in the security, privacy and integrity of your messages and files. PGP is an encryption program that was created by Phil Zimmerman back in the internet dark-age of Zimmerman, who was a staunch anti-nuclear activist, initially created the program so that like-minded individuals could communicate and store files more securely.
Zimmerman released PGP for free via FTP, making it the first form of public-key cryptography with widespread availability. It spread quickly over Usenet , particularly among peace and other political activists. From these roots, its usage grew outwards to those who wanted more privacy and security for their communications.
At the time, this type of cryptography was deemed a form of munition and required a license to be exported. Thankfully for Zimmerman, after several years of investigation and some imaginative legal maneuvering , no charges ended up being laid.
Over the years, new versions of PGP have continually been released to improve its security and its usability.
Some of these changes included restructuring the certificate system, implementing new symmetric and asymmetric algorithms and developing a new proxy-based architecture. This enabled anyone to implement OpenPGP into their software. This standard sets out the encryption algorithms, formats, composition and other features that programs must use to be OpenPGP-compliant. PGP encryption is used in a number of proprietary programs, such as the Symantec products mentioned above. The most prominent of these is Gpg4win , which is a free suite of encryption tools for Windows.
PGP encryption relies on several major elements that you will need to get your head around in order to understand how it works. The most important ones are symmetric-key cryptography, public-key cryptography , digital signatures and the web of trust. Symmetric-key cryptography involves using the same key to both encrypt and decrypt data.
In PGP, a random, one-off key is generated, which is known as the session key. The session key encrypts the message , which is the bulk of the data that needs to be sent. This type of encryption is relatively efficient, but it has a problem. How do you share the session key with your recipient? If you send it alongside your email, then anyone who intercepts the message can access the contents just as easily as your recipient.
Without the key, your recipient will only see the ciphertext. PGP solves this problem with public-key cryptography , also known as asymmetric cryptography. In this kind of encryption there are two keys: a public key and a private one.
Each user has one of each. The public key of your potential correspondent can be found by searching through key servers or by asking the person directly. Public keys are used by the sender to encrypt data, but they cannot decrypt it.
This is why public keys are freely handed out, but private keys need to be guarded carefully. If your private key is compromised by an attacker, it enables them to access all of your PGP encrypted emails.
Because public-key encryption is simply too inefficient. It would take too long and use a larger amount of computational resources. Since the body of the message usually contains the bulk of the data, PGP uses the more economical symmetric-key encryption for this.
It reserves the lumbering public-key encryption for the session key, making the whole process more efficient. In this way, the message gets encrypted through more practical means, while public-key encryption is used to securely deliver the session key to your recipient. Since only their private key can decrypt the session key, and the session key is needed to decrypt the message, the contents are secure from attackers. Our written signatures are frequently used to verify that we are who we say we are.
They are far from foolproof, but they are still a useful way of preventing fraud. Digital signatures are similar, using public-key cryptography to authenticate that the data comes from the source it claims to and that it has not been tampered with.
The process makes digital signatures essentially impossible to forge unless the private key has been compromised.
It all depends on what you are sending and why. If the message must be delivered intact and without alteration, then a digital signature will need to be used. If both are important, you should use them together. The plaintext of your message is fed through a hash function , which is an algorithm that transforms inputs into a fixed-size block of data, called a message digest.
This encrypted message digest is what is known as the digital signature. In PGP encryption, the digital signature is sent alongside the message body which can either be encrypted or in plaintext.
When someone receives a digitally signed email, they can check its authenticity and integrity by using the public key of the sender.
First, a hash function is used on the message that was received. This gives the message digest of the email in its current form. The next step is to calculate the original message digest from the digital signature that was sent. This gives the message digest exactly as it was when it was signed by the sender.
If the message had been altered by even one character or punctuation mark, then the message digests will be completely different. It may be an innocent mistake because the wrong public key has accidentally been used, but it could also be a fraudulent message or one that has been tampered with. How do you know that a public key actually belongs to the person who says it does? Thankfully, this was all thought of ahead of time and solutions were put in place. Otherwise, something so simple would completely undermine the whole system.
To prevent this kind of activity, the web of trust was developed. The web of trust grew as a way of vetting that each PGP public key and user ID are really connected to the person or organization that they are said to represent. The best part? It does it all without a central authority that can collapse or be corrupted. If you know a PGP user personally, you can confirm that their public key is linked to their actual identity.
You can put your trust in them and digitally sign their certificate, which shows that at least one person vouches for their identity. They can also do the same for you. If both of you meet one new PGP user each and digitally sign their certificates to verify their identities, you start to build a small network, where the four of you can trust the links between the public keys and identities, based on the trust each person has in others that they are linked to.
Over time, this builds an interconnected web of trust , with lots of people vouching for each other with digital signatures that verify their ownership of a public key. Sometimes it can be difficult for new users to find someone to sign their certificates and verify the relationship between themselves and their public key. This has been partially solved by key-signing parties , which are real-life meetups where users can assess whether keys belong to the person saying it does. There are different levels of trust, including full and partial.
Those that have many digital signatures on their certificates that represent full trust are seen as much more dependable than those with only a couple of partial-trust signatures. The web of trust allows users to assess for themselves whether they trust the digital certificate of a potential correspondent. If the message they want to send is extremely sensitive, they might decide that the risk is too great to send it to someone who only has partial trust. This is a common certificate standard that is also used for other purposes.
The main difference between PGP certificates and X. PGP certificates can be signed by certificate authorities as well, but X. In contrast to PGP certificates, which a user can make themselves, X. These certificates also only have a single digital signature from the issuer, as opposed to the many signatures that a PGP certificate can have from other users.
PGP can also be used to encrypt your attachments. There are a couple of ways to do this, but it will depend on your implementation. This prevents the leaking of metadata that occurs if each segment is encrypted separately.
You want to get the message out to journalists, but you are terrified for your own safety. What if the government finds out that you were the one who leaked the information and they send people after you? You eventually decide that releasing the information to the public is the right thing to do, but you want to do it in a way that protects you as much as possible.
You search online and find a journalist who is renowned for this kind of work and always protects their sources. You find it on their website or by searching a key-server.
You type out the message:. I have some information about a huge corruption scandal in The United States of Mozambabwe. Let me know if you are interested and I will send you more details. If you are worried about the email being tampered with, you can add your digital signature.