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在线凯撒密码加密解密工具，支持自定义字母表和偏移量，适合密码学学习与趣味使用。
Caesar cipher only works on English letters, numbers, punctuation and other characters will remain unchanged
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Vigenère Cipher Encoder & Decoder
Encrypt or decrypt text using the classic polyalphabetic substitution algorithm. Ideal for cryptography learning and testing.
Random Password Generator
Customize character types and length to generate strong random passwords and secure your accounts.
Morse Code Translator
Translate text to Morse code and vice versa. Features custom dot/dash symbols and audio playback for learning and communication.
Random Number Generator
Generate random integers or decimals within a specified range, featuring duplicate removal, sorting, and formatted output.
Vigenère Cipher Encoder & Decoder
Encrypt or decrypt text using the classic polyalphabetic substitution algorithm. Ideal for cryptography learning and testing.
Random Password Generator
Customize character types and length to generate strong random passwords and secure your accounts.
Morse Code Translator
Translate text to Morse code and vice versa. Features custom dot/dash symbols and audio playback for learning and communication.
Random Number Generator
Generate random integers or decimals within a specified range, featuring duplicate removal, sorting, and formatted output.
CRC16 Checksum Calculator
Online CRC16 checksum tool to calculate 16-bit cyclic redundancy check values for text, Hex, and Base64 data to verify data integrity.
Shift every letter in "HELLO" forward by 3 positions, and it becomes "KHOOR"—this is the core shifting concept of the Caesar cipher. Legend has it that Julius Caesar of ancient Rome used this substitution encryption to protect the contents of his military communications. It is a type of substitution cipher in classical cryptography: each letter in the plaintext is cyclically shifted along the alphabet by a fixed offset to produce the ciphertext. Our calculator operates around this "shift and substitute" principle. You can choose the standard alphabet (A-Z, a-z, 0-9) or customize any character sequence.
Although the Caesar cipher is simple, it is an indispensable starting point in cryptography education and frequently appears in fun puzzles and beginner cybersecurity challenges (CTFs).
During encryption, assuming we encode the letters A to Z sequentially as 0 to 25, with a shift value of n (0 ≤ n < 26), the ciphertext y corresponding to the plaintext letter x is:y = (x + n) mod 26
For decryption, simply shift in the reverse direction:x = (y - n) mod 26
"mod" represents the modulo operation (remainder), which ensures that shifting past the end of the alphabet loops back to the beginning. For example, shifting Z (encoded as 25) by 1 → (25+1
