Passer au contenu principal

Text Encryption

Encrypt and decrypt text with Caesar, ROT13, Vigenère, Atbash, Morse, Base64, Binary and Hexadecimal. Brute-force and frequency analysis included.

Algorithm
Mode

History

No encryption yet.

How does text encryption work?

Encryption transforms readable text (plaintext) into unreadable text (ciphertext) using an algorithm and a key. Decryption is the reverse operation. The algorithms shown here are classical ciphers for educational purposes — they are not secure for professional use (use AES or ChaCha20 for sensitive data).

Caesar cipher and ROT13

The Caesar cipher shifts each letter of the alphabet by a fixed number of positions (the key). With a key of 3, A→D, B→E, etc. It is one of the oldest known algorithms, used by Julius Caesar for military communications. ROT13 is a special case with a shift of 13 — applying ROT13 twice returns the original text.

Vigenère cipher

The Vigenère cipher uses a keyword to apply multiple Caesar shifts cyclically. With key "KEY", the 1st letter is shifted by 10 (K), the 2nd by 4 (E), the 3rd by 24 (Y), then repeats. It is much more robust than Caesar because the same letter can be encrypted differently depending on its position.

Frequently asked questions

Encryption protects data confidentiality: without the key, the ciphertext is unreadable. Encoding (Base64, Binary, Hex) simply converts the data representation ... Encryption protects data confidentiality: without the key, the ciphertext is unreadable. Encoding (Base64, Binary, Hex) simply converts the data representation format — without protection. Anyone can decode Base64 without a key. In this tool, Base64, Binary and Hexadecimal are encodings, not encryption. Caesar, ROT13, Vigenère and Atbash are classical ciphers (weak compared to modern standards).

The Caesar cipher has only 25 possible keys (shifts 1 to 25). A brute-force attack tries all keys and displays the 25 possible decryptions. The human reads the ... The Caesar cipher has only 25 possible keys (shifts 1 to 25). A brute-force attack tries all keys and displays the 25 possible decryptions. The human reads the results and identifies the intelligible text. Click on the corresponding row to apply that shift automatically. This is why the Caesar cipher is considered cryptographically useless against a modern attack.

The Coincidence Index measures the probability that two randomly chosen letters in a text are identical. For unencrypted French or English text, the IC is about... The Coincidence Index measures the probability that two randomly chosen letters in a text are identical. For unencrypted French or English text, the IC is about 0.065-0.075. For text encrypted by monoalphabetic substitution (Caesar, Atbash), the IC remains similar because relative frequencies are preserved. For a polyalphabetic cipher (Vigenère) or truly random text, the IC drops towards 0.038. This helps identify the type of encryption used.

No, not by modern standards. The Vigenère cipher was considered 'unbreakable' for 300 years until Charles Babbage and Friedrich Kasiski discovered attack method... No, not by modern standards. The Vigenère cipher was considered 'unbreakable' for 300 years until Charles Babbage and Friedrich Kasiski discovered attack methods in the 19th century. The Kasiski method finds the key length, then frequency analysis decrypts each position. For truly sensitive data, use modern algorithms like AES-256-GCM or ChaCha20-Poly1305.

No. The algorithms shown (Caesar, ROT13, Vigenère, Atbash, Morse, Base64, Binary, Hex) are educational tools for understanding cryptography concepts. They are n... No. The algorithms shown (Caesar, ROT13, Vigenère, Atbash, Morse, Base64, Binary, Hex) are educational tools for understanding cryptography concepts. They are not secure for protecting passwords, personal data or confidential communications. For secure encryption, use proven solutions: VeraCrypt for files, Signal for messaging, or the Web Crypto API library (AES-GCM) for web applications.

Tools in the same category

Password Generator IP Address Checker Security Headers Analyzer Phishing Link Checker UUID Generator Vérificateur de mot de passe

Popular tools

AI Alt Text Generator OCR Text Extractor Smart Hashtag Generator IP Address Checker Currency Converter 2026

Trending tools

Voltage Converter HTML Viewer Tax Calculator 2026 Amazon FBA Calculator
Lien copié !