7 Best Free Online Polybius Square Decoder Websites

Here is a list of best free online Polybius square decoder websites. Polybius square or Polybius square cipher is a classical cryptographic substitution technique that involves the substitution of letters with a pair of numerical coordinates. The numerical coordinates used in this technique are usually represented as row and column numbers in a grid. This algorithm is used to encrypt and decrypt text information. At times, it is necessary to retrieve the original data encrypted using this Polybius square algorithm. To do that, you can check out these online Polybius square decoder websites.

Through these websites, users can quickly decode or decrypt data encoded using Polybius square encoders. To do that, these websites require three primary parameters namely Polybius square encrypted data, alphabets used during encryption, and rows & column data. However, some of these decoders need some additional information for decoding operations like separator, key length, etc. After decoding the cipher, users can view the original data. To help you out, I have included the necessary decoding steps in the description of each website.

These websites offer multiple cipher tools such as Atbash Cipher, Caesar Cipher, Autokey Cipher, Running Key Cipher, and more. Go through the list to learn more about these websites.

My Favorite Online Polybius Square Decoder Website:

dcode.fr is my favorite website as it offers three different Polybius square decoding methods. Plus, it explains the Polybius square algorithm.

You can also check out lists of best free Online Bacon Cipher, Online Hex Decoder, and Online JWT Decoder websites.

Comparison Table:

Features/Website Names	Performs both encoding and decoding operations	Explains Polybius cipher	Offers multiple cipher tools
dcode.fr	✓	✓	✓
braingle.com	✓	✓	✓
cryptii.com	✓	x	✓
cachesleuth.com	✓	x	✓
md5encrypt.net	✓	✓	✓
interactive-maths.com	✓	✓	✓
organisingchaos.com	✓	x	✓

dcode.fr

dcode.fr is a free online Polybius square decoder website. This website offers multiple cipher tools including a Polybius square decoder. This decoder allows users to retrieve the original information from an encrypted piece of cipher text. It offers three Polybius square decoding methods namely Automatic Decryption, Transform in mono-alphabetic substitution, and Encrypted grid (requires the right grid pattern). Before starting the description process, users can also specify coordinates order (Line, Column, or Column, Line). An inbuilt Polybius Square Encoder is also offered by it. Now, follow the below steps.

How to decode cipher text online using dcode.fr:

Visit this website and access the Polybius Square Decoder.
After that, enter the Polybius cipher text in the input field.
Next, choose one of three available decoding methods.
Finally, choose a coordinates order and click on the Decrypt button to view the original text information.

Additional Features:

This website has multiple cryptography tools like Polygrammic Cipher, Transposition Cipher, Substitution Cipher, Modern Cryptography, and more.

Final Thoughts:

It is one of the best free online Polybius Square decoder websites that offers three different methods to decode ciphertext using the Polybius Square algorithm.

Pros	Cons
Performs both encoding and decoding operations
Offers three decoding methods

Home Page

braingle.com

braingle.com is a free online Polybius square decoder website. This website can quickly decrypt or decode cipher text encoded using the Polybius square algorithm. It can also be used to encrypt plain text into cipher text. It also explains the Polybius square cipher with the help of examples. Now, follow the below steps.

How to decode cipher text online using braingle.com:

Visit this website and access the Polybius Square Cipher.
After that, enter the encoded cipher text in the CIPHERTEXT field.
Now, click on the Decipher button to view the original text.

Additional Features:

This website offers multiple cipher tools such as Caesar Cipher, Atbash Cipher, Keyword Cipher, Autokey Cipher, and more.

Final Thoughts:

It is a good online Polybius square decoder website that uses Polybius square cipher to decode and encode information.

Pros	Cons
Explains Polybius Square Cipher
Performs both encoding and decoding operations

Home Page

cryptii.com

cryptii.com is another free online Polybius square decoder website. Users can decode cipher text encoded by the Polybius square algorithm to reveal the original text information. Similar to decoding, it can also be used to encode plain text to cipher text using this algorithm. Before doing the decoding operation, users need to specify the original set of alphabets rows, and columns used at the time of encryption. Users can also choose a separator to add to the decoded text. Besides this, case sensitivity and foreign chars can also be adjusted. Now, follow the below steps.

How to decode cipher text online using cryptii.com:

Visit this website using the given link.
After that, enter plain text in the input section.
Now, choose the Decode option and specify the values of alphabets, rows, and columns.
Next, specify a separator if you want to add separators between the original text.
Finally, view and copy the decoded text from its interface.

Additional Features:

This website supports various types of ciphers like the Enigma Machine, Caesar Cipherm Affine Cipher, Bacon Cipher, and more.

Final Thoughts:

It is another good online Polybius square decoder that supports both encoding and decoding operations and allows users to adjust multiple decoding parameters.

Pros	Cons
Performs both encryption and decryption operations	Doesn’t offer information related to Polybius Cipher
Lets users specify cipher alphabets, row values, and column values
Can add separators into decoded data

Home Page

cachesleuth.com

cachesleuth.com is another free online Polybius square decoder website. This website offers a Polybius square cipher section that contains both decoding and encoding tools. To perform the decryption, it primarily needs encrypted cipher text, alphabets used during encoding, and ciphertext key. It also offers some advanced options that users can use at the time of the Polybius square encoding process. However, this website doesn’t offer much information related to Polybius square decoding. Now, follow the below steps.

How to decode cipher text online using cachesleuth.com:

Visit this website and access the Polybius Square Cipher section.
After that, enter encrypted text in the Ciphertext field
Now, specify the ciphertext key and alphabets.
Finally, click on the Decrypt button to view the original text without space between words.

Additional Features:

This website offers a good number of Multi-Decoder, Cipher, Code, and Map tools.

Final Thoughts:

It is another good online cipher text decoder website that anyone can use to decode data encoded through Polybius square cipher.

Pros	Cons
Performs both encoding and decoding operations	Lacks information associated with Polybius cipher
Easy to use

Home Page

md5encrypt.net

md5encrypt.net is another free online Polybius square decoder website. This website offers one of the simplest Polybius square decoders as it only needs encrypted cipher text as input to perform the Polybius square decoding. However, users can also enter the key with the cipher text but it’s completely optional. Apart from deciding, it can also perform Polybius square encoding operation. It also explains the Polybius Square algorithm along with the Polybius square decryption process. Now, follow the below steps.

How to decode cipher text online using md5encrypt.net:

Visit this website and open up the Polybius Square Encrypt & Decrypt tool.
After that, enter a cipher text in the input field.
Next, enter a key if you want.
Finally, click on the Decrypt button to view the original text.

Additional Features:

This website has multiple online tools such as MD5 Decryption, Xor Decryption, Hash Finder, Brainfuck Decoder, Leet Translator, and more.

Final Thoughts:

It is another simple online Polybius square decoder website that anyone can use without much hassle.

Pros	Cons
Performs both encoding and decoding operations
Explains Polybius Square algorithm

Home Page

interactive-maths.com

interactive-maths.com is a free online Polybius square decoder website. This website offers a Crypto Corner tool that helps users decode cipher text encoded through the Polybius square algorithm. Along with Ciphertext, it also needs a key, number of rows, number of columns, and used alphabet data to perform the Polybius square decoding process. Similar to decoding, it can also be used to encode plain text into cipher text using this algorithm. This website also explains the workings of the Polybius square algorithm. Now, follow the below steps.

How to decode cipher text online using interactive-maths.com:

Visit this website using the given link.
After that, enter the cipher text in the cipher text field.
Now, enter key, alphabets, rows, columns, etc., data.
Finally, click on the Decrypt button to start the calculation process.

Additional Features:

This website has multiple online tools such as Atbash Cipher, Pigpen Cipher, Affine Cipher, Caesar Shift Cipher, Polyalphabetic Substitution Cipher, and more.

Final Thoughts:

It is another simple online Polybius square decoder website that helps users perform both encoding and decoding operations.

Pros	Cons
Performs both encoding and decoding operations
Explains Polybius Square algorithm
Offers additional cipher tools

Home Page

organisingchaos.com

organisingchaos.com is another free online Polybius square decoder website. This website helps users find the original information encrypted through the Polybius square algorithm. To do that, you need ciphertext, key, square size, and shared letters information. Apart from ciphertext decoding, users can also use it to encode plain text into cipher text using the Polybius square algorithm. Now, follow the below steps.

How to decode cipher text online using organisingchaos.com:

Visit this website using the given link.
After that, enter the encoded ciphertext.
Now, enter key, square size, and shared letters data.
Finally, click on the Decrypt button to view the original data.

Additional Features:

This website offers multiple similar tools such as Monoalphabetic Substitution, Transposition Ciphers, Machine Ciphers, Odd Bits, and more.

Final Thoughts:

It is another good online Polybius square decoder website that anyone can use with ease.

Pros	Cons
Performs both encoding and decoding operations
Offers additional cipher tools

Home Page

Frequently Asked Questions

What is Polybius square cipher?

Polybius square or Polybius square cipher is a classical cryptographic substitution technique that involves the substitution of letters with a pair of numerical coordinates. The numerical coordinates used in this technique are usually represented as row and column numbers in a grid. This algorithm is used to encrypt and decrypt text information.

Who made the Polybius square?

The Polybius Square is attributed to the ancient Greek historian and scholar Polybius, who lived in the 2nd century BCE. Polybius is best known for his work "Histories," where he documented the history of the Mediterranean world during his time. However, it's essential to note that while the Polybius Square is named after him, it's not clear whether Polybius himself invented this specific cryptographic technique or if it was developed later based on his ideas.

What is the standard Polybius square?

There isn't actually just one "standard" Polybius Square. However, several versions are considered more common or "classic," particularly the two listed: Classical Greek Square and English Language Square. The Classical Greek Square uses the Greek alphabet instead of the Latin alphabet, arranged in alphabetical order within a 5x5 grid. This was the original form described by Polybius himself. On the other hand, English Language Square replaces the Greek alphabet with the 26 letters of the English alphabet (excluding J, which is often combined with I). You'll find several variations of this, with the most common arrangement having the first five letters (A-E) in the first row, and continuing alphabetically row by row.

Why was Polybius square invented?

The most likely and widely accepted purpose is for military communication. Polybius described its use for signaling messages between distant military units using torches or other visual means. The 5x5 grid allowed for representing any letter with just two signals (one for the row, one for the column). This simple system offered an advantage over older methods that relied on a limited set of pre-determined signals.

What is the 4 square code?

It is a manual symmetric encryption technique that encrypts pairs of letters (digraphs) using four 5x5 substitution squares.

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