Many people think that data security is all about advanced firewalls and antivirus programs. But it actually starts with something much simpler: making text unreadable to anyone who shouldn’t see it. How? By transforming it into what’s called “ciphertext.”
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Once you understand what ciphertext is, how it works, and how you probably use it dozens of times a day without even realizing it, you’ll see just how crucial modern cryptography is for keeping your digital life safe.
What is ciphertext, exactly?
Ciphertext is encrypted text, made unreadable to anyone without the right key. It’s produced by taking normal, readable content—called plaintext—and running it through an encryption algorithm, which scrambles it into a seemingly random mix of letters, numbers, and symbols. Only someone with the correct decryption key can convert ciphertext back into its original, readable form.
While running text through an encryption algorithm might sound like complicated technical work, it’s actually very common. In fact, you likely interact with ciphertext every day without even realizing it. Every secure website connection marked by “HTTPS,” every private message sent via a secure chat application, every password saved in a reputable password manager—all of these involve the use of ciphertext.
Ciphertext is also one of the key tools that keeps your banking and personal information secure whenever you transmit, store, or share it online.
Ciphertext vs. plaintext: What’s the difference?
To fully grasp the significance of ciphertext, we must contrast it with plaintext.
Plaintext is any readable, non-encrypted data. It can be the body of an email, the text of a document, or the password you enter into a login field. If this data were transmitted or stored in its original form, anyone who intercepts it could read and use the information immediately, without any special tools or effort.
Ciphertext, by contrast, is the form data takes after it has been encrypted by a cipher. The cipher applies a defined mathematical algorithm along with a secret key to convert readable data into an unintelligible string of characters. If someone who isn’t authorized gets hold of the ciphertext, they just see an unintelligible jumble of characters. Without the secret key, the data can’t be read or used.
Ciphertext example
To see how this works in practice, let’s look at a simple example using a basic substitution cipher.
Imagine your original message, in plaintext, is:
“I WANT MY DATA TO BE SECURE”
Then, let’s have the cipher apply a simple rule to shift each letter three places forward in the alphabet to turn it into the ciphertext. The result is:
“L ZDQW PB GDWD WR EH VHFUXUH”
At first glance, this string of characters looks like nonsense. And that’s exactly the point. If someone intercepts it, they can’t make any sense of it. Only the person who knows the “secret code”—in this case, the “shift by three” rule—can decode it back into the original message.
Of course, modern encryption is far more complex than this, using long keys and sophisticated algorithms. But the basic principle remains the same: it's all about transforming readable data into something completely unintelligible to anyone without the key.
So, why is ciphertext important?
Ciphertext is important because it provides the essential first layer of protection for sensitive data. By converting plaintext into ciphertext, you ensure that information is transmitted securely across the internet.
Logging into an account is another great example. When you enter your password, it has to pass through multiple networks to reach the server. If it were sent unprotected in plaintext form, anyone intercepting it along the way could see it and immediately gain access to your account.
To prevent this, your password is transformed into ciphertext using a secure protocol before leaving your device. The decryption key needed to recover the plaintext is never exposed during transmission; only the ciphertext travels across the network. This ensures that if a threat actor intercepts the data, they won’t be able to read your password.
This process is essential for protecting digital communications, from personal emails to international financial transactions and other sensitive data.
The two main types of ciphers
Ciphers that transform plaintext into ciphertext are generally categorized into two main types based on their key structure.
Symmetric-key ciphers
Symmetric-key ciphers rely on a single cryptographic key, which is used for both encryption and decryption. In other words, the sender uses this key to transform plaintext into ciphertext, and the recipient uses the identical key to revert it back to plaintext. This process is carried out using a symmetric key algorithm.
The primary advantage of this approach is its speed and efficiency. Symmetric key encryption requires less computational power, which makes it well-suited for encrypting large volumes of data, such as securing entire disk drives or protecting the main content of a secure web session.
The main challenge, however, lies in securely distributing the key to the recipient before communication begins. If the key is compromised, all encrypted data is at risk.
Asymmetric-key ciphers
Asymmetric-key ciphers, also called public-key cryptography, resolve the key distribution problem by employing a mathematically linked pair of keys: a public key and a private key. The public key can be shared openly and is used solely to encrypt plaintext into ciphertext, while the private key is kept confidential and is the only key capable of decrypting the ciphertext into plaintext.
This approach eliminates the need to transmit a secret key securely. Anyone can use the public key to send an encrypted message, but only the intended recipient with the private key can read it. The trade-off is that asymmetric-key encryption is mathematically more complex and therefore slower, sometimes even by orders of magnitude, than the symmetric method.
The hybrid approach
Some modern cryptographic systems combine both methods. They use slower, highly secure asymmetric-key ciphers to safely exchange or derive a symmetric key, and then rely on the efficient symmetric-key algorithm to encrypt the bulk of the data transfer. This approach is commonly used in secure web communications, cloud storage, and financial transactions, where both quick data processing and secure key exchange are critical.
How NordPass protects your passwords with encryption
As a technologically advanced password manager, NordPass leverages the latest cybersecurity standards and encryption algorithms to protect your data.
As a matter of fact, NordPass is the only major password manager to use XChaCha20, widely regarded as one of the most secure encryption algorithms available today. By employing XChaCha20 to protect the contents of your vault, NordPass goes beyond the standard AES-256, an older yet still strong cipher.
Additionally, NordPass is built on a zero-trust principle, meaning your passwords and sensitive information are encrypted locally on your device before being uploaded to the cloud. As a result, only the intended recipients—either just you or those you choose to share with—can access your data; not even we at NordPass can see it. This approach ensures that the security and privacy of your digital credentials remain entirely under your control.