Cryptography
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Elliptic Curve Explorer
Observation point addition and doubling operations on real curves and finite fields.
Educational use; finite field restricts small primes to complete point set display, not for production key operations.
Cipher Round Explorer
View status changes of AES-128 or ChaCha20 round by round.
AES is a single block encryption tutorial, ChaCha20 shows a block function; key management and production message encryption are not provided.
Proof & Lattice Lab
Verify the Schnorr interactive proof of equality, or observe the two-dimensional lattice basis reduction.
Schnorr Reproducible teaching transcript using small fixed groups; 2D Gauss reduction; no production cryptography security.
Hash Digest
Computes the standard digest and compares the bit difference after appending one character.
UTF-8 text hash; the avalanche example only compares two deterministic inputs and is not a proof of algorithm security.
HMAC Test Vector
generates HMAC-SHA256 public test vectors.
is for debugging and teaching and does not store production keys; keys and messages are encoded in UTF-8.
Byte Encoding
byte-encode or strictly decode text.
Base64 and Hex are encodings and do not provide confidentiality; the decoded result must be valid UTF-8.
Modular Exponentiation
progressively displays the modular exponentiation state by binary square multiplication.
Finite teaching integers, exact integer arithmetic using Python. The
Extended Euclidean Algorithm
finds the greatest common divisor, Bézout coefficient, and modular inverse when they exist.
is an exact integer; the modular inverse only exists when the two numbers are relatively prime.
Toy RSA Lab
uses small prime numbers to demonstrate the consistency of public and private key exponents, encryption and decryption.
Teaching bare RSA, insecure, not used for real messages; prime numbers and exponents are verified.
Shamir Secret Sharing
Generates small teaching shares and validates threshold reconstructions in finite domains.
uses fixed public polynomial coefficients, which cannot protect the real secret; it does not randomly generate production keys.
Caesar Shift
Caesar Shift Tutorial: Perform deterministic calculations and derive verifiable results.
History teaching algorithm without modern cryptographic security. Only English letters are transformed, and the rest of the characters are retained.
Vigenere Cipher
Virginia Cipher Tutorial: Perform deterministic calculations and derive verifiable results.
History teaching algorithm without modern cryptographic security. Only English letters are transformed, and the rest of the characters are retained.
Affine Cipher
Tutorial on Affine Cryptography: Perform deterministic calculations and derive verifiable results.
History teaching algorithm without modern cryptographic security. Only English letters are transformed, and the rest of the characters are retained.
Atbash Cipher
Atbash alphabet mirror: Perform deterministic calculations and export verifiable results.
History teaching algorithm without modern cryptographic security. Only English letters are transformed, and the rest of the characters are retained.
Rail Fence Cipher
Fence Transposition Tutorial: Perform deterministic calculations and derive verifiable results.
History teaching transposition password, including spaces and other characters.
Letter Frequency
Letter Frequency Analysis: Perform deterministic calculations and derive verifiable results.
only counts A–Z, and the frequencies themselves do not automatically crack modern passwords.
Index of Coincidence
Letter Coincidence Index: Perform deterministic calculations and derive verifiable results.
is suitable for teaching historical password statistics.
Bit Hamming Distance
Byte-bit Hamming distance: Perform deterministic calculations and derive verifiable results.
input is for public test vectors only; do not upload real passwords, private keys, or sensitive plaintext.
SHA256 Avalanche
SHA-256 Avalanche Demonstration: Perform deterministic calculations and derive verifiable results.
input is for public test vectors only; do not upload real passwords, private keys, or sensitive plaintext.
SHAKE256 XOF
SHAKE256 Variable-length summary: Perform deterministic calculations and derive verifiable results.
input is for public test vectors only; do not upload real passwords, private keys, or sensitive plaintext.
PBKDF2 SHA256 Vector
PBKDF2 test vector: Perform deterministic calculations and derive verifiable results.
input is for public test vectors only; do not upload real passwords, private keys, or sensitive plaintext.
scrypt Test Vector
scrypt test vector: performs deterministic calculations and derives verifiable results.
input is for public test vectors only; do not upload real passwords, private keys, or sensitive plaintext.
CRC32 Checksum
CRC32 data verification: perform deterministic calculations and derive verifiable results.
is used for error detection, not for authentication or cryptographic integrity.
AES GF256 Multiplication
AES Finite Field Multiplication: Perform deterministic calculations and derive verifiable results.
input is for public test vectors only; do not upload real passwords, private keys, or sensitive plaintext.
Chinese Remainder Solver
Chinese Remainder Theorem Solver: Perform deterministic calculations and derive verifiable results.
Coprime modulus only, integer scale-restricted tutorial solution.
Bounded Primality Test
Bounded integer primality test: Perform deterministic calculations and derive verifiable results.
Up to 10⁹, returns deterministic results.
Euler Totient
Euler φ function: Performs deterministic calculations and derives verifiable results.
bounded integer decomposition, φ(1)=1.
Multiplicative Order
Modular Multiplication Order: Perform deterministic calculations and derive verifiable results.
Teaching bounded multiplicative groups without asking for large discrete logarithms.
Empirical Byte Entropy
Byte Empirical Entropy: Perform deterministic calculations and derive verifiable results.
Up to 256 class bytes, limited sample empirical frequency.
PKCS7 Padding
PKCS#7 padding check: Perform deterministic calculations and derive verifiable results.
exhibits padding and local round-trip authentication, and does not implement the decryption interface.
Understand the method and then start calculating
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