A simple shift substitution cipher where each letter in the plaintext is shifted by a fixed number of positions.
Open visualizer →Cipher visualizer
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Pin frequently used algorithms, revisit recent ciphers, and inspect each operation through an interactive step-by-step trace.
Classical
Explore foundational substitution and transposition techniques.
A special case of Caesar cipher with a fixed shift value of 13.
Open visualizer →A polyalphabetic substitution cipher that uses a keyword to shift characters in repeating cycles.
Open visualizer →A monoalphabetic substitution cipher formed by reversing the alphabet (A becomes Z, B becomes Y, etc.).
Open visualizer →A polygraphic substitution cipher that encrypts pairs of letters using a dynamic 5x5 key matrix.
Open visualizer →A transposition cipher where plaintext is written diagonally down and up on successive "rails" of a fence.
Open visualizer →Ancient Greek grid cipher encoding each letter as a (row, col) coordinate pair in a 5×5 grid. J is merged into I.
Open visualizer →A polyalphabetic substitution cipher that reverses the Vigenère formula (K - P instead of P + K), making it self-inverse.
Open visualizer →Keyed transposition cipher — plaintext is written in rows then columns are read in alphabetical key order.
Open visualizer →A polygraphic substitution cipher that encrypts pairs of letters using 2x2 matrix multiplication modulo 26.
Open visualizer →A stronger variant of Vigenère where the keystream extends using the plaintext itself instead of repeating the key, removing Kasiski-style periodicity.
Open visualizer →A WWI-era cipher combining a keyed 6x6 Polybius-square substitution with a keyed columnar transposition.
Open visualizer →A polygraphic substitution cipher (Delastelle) that encrypts letter pairs using two keyed 5x5 grids alongside two standard alphabet grids.
Open visualizer →Symmetric
Study shared-key encryption, block ciphers, and stream operations.
A simple stream cipher performing byte-wise XOR operations between plaintext and key.
Open visualizer →An unbreakable cipher when used with a truly random, single-use key of equal length to the plaintext.
Open visualizer →Data Encryption Standard. A legacy 64-bit block cipher utilizing a 56-bit key size.
Open visualizer →Applies the DES algorithm three times to each data block with two or three keys to increase security.
Open visualizer →Advanced Encryption Standard. A highly secure, standard block cipher supporting key sizes of 128, 192, or 256 bits.
Open visualizer →Authenticated encryption (AEAD): AES in counter mode for confidentiality plus a GHASH authentication tag for integrity. Used by TLS 1.3 and WireGuard — flipping a single ciphertext byte makes tag verification fail.
Open visualizer →A byte-oriented stream cipher combining a Key-Scheduling Algorithm (KSA) with a Pseudo-Random Generation Algorithm (PRGA) to produce a keystream.
Open visualizer →A modern ARX-based stream cipher (Bernstein, 2005) built from add-rotate-XOR quarter-rounds — the direct predecessor to ChaCha20.
Open visualizer →A modern ARX-based stream cipher (RFC 8439) used in TLS 1.3, built from add-rotate-XOR quarter-rounds instead of substitution boxes.
Open visualizer →A compact 64-round Feistel cipher (Wheeler & Needham, 1997) using only addition, XOR, and shifts — no lookup tables.
Open visualizer →Asymmetric
Understand public-key cryptography and secure key exchange.
An asymmetric cipher based on the difficulty of factoring large semiprimes. Supports key generation, encryption, and decryption.
Open visualizer →A key exchange protocol enabling two parties to establish a shared secret over an insecure channel.
Open visualizer →Elliptic Curve Cryptography. Implements ECDSA signing and verification over the NIST P-256 curve.
Open visualizer →A public-key encryption scheme based on the discrete logarithm problem, using ephemeral-key modular exponentiation.
Open visualizer →Edwards-curve Digital Signature Algorithm — deterministic signatures over Curve25519, with no external randomness and no nonce-reuse failure mode.
Open visualizer →Hashing
Inspect hashing, message authentication, and password derivation.
Secure Hash Algorithm 2. Produces a unique 256-bit (32-byte) hash output representing the input message.
Open visualizer →Secure Hash Algorithm 2 with 64-bit words, producing a secure 512-bit (64-byte) digest.
Open visualizer →A widely used legacy hash producing a 128-bit output. Cryptographically broken due to collision vulnerabilities.
Open visualizer →Keyed-hash Message Authentication Code. Combines SHA-256 with a cryptographic secret key.
Open visualizer →A password hashing function incorporating a salt and cost factor, designed to be slow to prevent brute force.
Open visualizer →NIST FIPS 202 hash function using the Keccak sponge construction — 24-round permutation over a 1600-bit state.
Open visualizer →Legacy 160-bit hash function (NIST FIPS 180-1). Cryptographically broken — SHAttered collision attack demonstrated in 2017.
Open visualizer →A 160-bit hash function using two independent, parallel compression lines whose final states are combined by modular addition.
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