Crypto & Hashing
Cryptographic and hashing utilities: JWT decode/verify/generate, MD5/SHA hash generators, HMAC signatures, UUID generators. WebCrypto-backed where the browser supports it.
All Crypto & Hashing
- JWT Decoder Decode, verify, and generate JWTs. HS256, RS256, ES256, EdDSA support.
- Hash Generator Generate MD5, SHA-1, SHA-256, SHA-512, BLAKE2 hashes in your browser.
- HMAC Generator Compute HMAC signatures with SHA-256, SHA-512, and other digests.
- UUID Generator Generate UUID v1, v4, v7. Bulk generation up to 1,000 at a time.
- JWT Generator Generate signed JWTs with HS256/HS384/HS512, RS256, ES256. Quick payload editor.
- Secure Password Generator Cryptographically random passwords with configurable length and character classes.
- Password Strength Checker Check password entropy and crack time. Browser-only — never sent anywhere.
- Credit Card / Luhn Validator Validate credit card numbers with the Luhn algorithm. Detect card brand. Browser-only.
- IBAN Validator Validate IBAN — format, country, mod-97 checksum.
- OAuth Scope Decoder Decode OAuth scope strings for Google, GitHub, Microsoft. See what each scope grants.
- Bcrypt Hash Generator & Verifier Generate and verify bcrypt password hashes. Configurable cost factor. Browser-only.
- BLAKE3 Hash Generator BLAKE3 — fast modern hash. 256-bit output, configurable length.
- PEM ↔ DER Converter Convert X.509 certificates and keys between PEM (Base64) and DER (binary).
- Test Credit Card Number Generator (Luhn-Valid) Generate Luhn-valid test card numbers for development. Visa, Mastercard, Amex test BINs. Sandbox only.
- File Hash Calculator (SHA-256, SHA-1, MD5) Drop a file, get SHA-256 / SHA-512 / SHA-1 / MD5 hashes calculated in your browser. Verify downloads against published checksums.
- Password Leak Check (Pwned Passwords API) Check if a password appears in known data breaches using HaveIBeenPwned k-anonymity API. Password never leaves browser.
- RSA Keypair Generator (2048 / 4096-bit) Generate RSA public + private keypair in PEM format. WebCrypto, runs in browser, never sent anywhere.
- Ed25519 Keypair Generator Generate an Ed25519 public + private keypair. Modern, fast, used by SSH / GPG / JWT EdDSA.
- SSH Public Key Fingerprint Calculator Calculate the SHA-256 fingerprint of an SSH public key. Matches ssh-keygen output.
- UUIDv7 Generator (Time-Ordered) Generate UUIDv7s — time-ordered UUIDs ideal for database primary keys. Sortable, distributed-friendly.
- TOTP / 2FA Code Generator (RFC 6238) Generate TOTP 6-digit codes from a base32 secret. Live updating, like Google Authenticator. Browser-only.
- SWIFT / BIC Code Validator Validate SWIFT / BIC bank codes. Decodes bank, country, and branch.
- Test IBAN Generator (Mod-97 Valid) Generate Mod-97-valid test IBANs for development. 30+ country formats. Sandbox use only.
- WebAuthn Passkey Tester (Register + Verify) Test WebAuthn / passkey registration and assertion in your browser. No backend needed.
- UUID Validator (v1–v8, Detect Version) Validate any UUID. Detects version (1, 3, 4, 5, 6, 7, 8) and variant. Decodes timestamps from v1 / v6 / v7.
- Password Policy Builder (Regex Generator) Visually build a password policy (min length, uppercase, digit, symbol, no spaces). Generates regex, JS, and HTML pattern attribute.
- JWT Builder + Signer (HS256, RS256) Build and sign a JWT in your browser. HS256 (HMAC), RS256 (RSA). Specify header, claims, secret / private key.
- AES-GCM Encrypt / Decrypt Tool Encrypt and decrypt with AES-256-GCM in your browser. PBKDF2 password-derived keys. WebCrypto-based, secure.
- HMAC Signature Verifier (Webhooks: Stripe, GitHub, Slack) Verify HMAC-SHA256 signatures on webhook payloads. Supports Stripe / GitHub / Slack signing formats.
- JWT + JWKS Verifier (Public Key Discovery) Verify a JWT against a JWKS endpoint URL. Fetches public key, validates signature, decodes claims.
- Ed25519 Sign + Verify (Message Authentication) Sign and verify messages with Ed25519. Generate keypair, sign, verify against public key. WebCrypto.
- UUID to Base62 (Short ID) Converter Convert UUIDs to compact base62 strings (Bitly-style short IDs) and back. 22 chars vs 36.
- CRC32 Checksum Calculator Compute the CRC32 checksum of text in hex and decimal. Matches zip/gzip/PNG CRC32 (IEEE polynomial).
- NanoID Generator Generate URL-safe NanoIDs in bulk. Custom length and alphabet; cryptographically random via WebCrypto.
- Snowflake ID Decoder (Twitter/Discord) Decode Twitter/Discord Snowflake IDs into timestamp, worker, process, and sequence components.
- CRC-16 Calculator (Modbus, CCITT, XMODEM) Compute CRC-16 across common variants — ARC, Modbus, CCITT-FALSE, XMODEM, Kermit — in hex and decimal.
- Adler-32 Checksum Calculator Compute the Adler-32 checksum used in zlib and PNG, in hex and decimal, with its two component sums.
- FNV Hash Calculator (FNV-1 / FNV-1a) Compute the FNV-1 and FNV-1a non-cryptographic hash in 32-bit and 64-bit, in hex and decimal.
- CRC-8 Calculator — All Common Variants Compute CRC-8 across eight variants — SMBus, Maxim/1-Wire, DVB-S2, CDMA2000, ROHC, WCDMA — in hex and decimal.
- Fletcher Checksum Calculator Compute the Fletcher-16 and Fletcher-32 checksums of text or hex, with both running sums, in hex and decimal.
- Internet Checksum Calculator (RFC 1071) Compute the 16-bit one's-complement Internet checksum from RFC 1071, used in IPv4, ICMP, TCP, and UDP.
- CRC-64 Calculator (XZ, ECMA-182, ISO) Compute the CRC-64 checksum across the XZ, ECMA-182, and GO-ISO variants of text or hex, in hex and decimal.
- MurmurHash3 Calculator (32-bit) Compute the MurmurHash3 x86 32-bit non-cryptographic hash of text with an optional seed, in hex and decimal.
- djb2 Hash Calculator (djb2, sdbm, Java) Compute the djb2, djb2a, sdbm, and Java String.hashCode non-cryptographic hashes of text, in hex and decimal.
- ULID Generator Generate ULIDs — 128-bit, lexicographically sortable, Crockford base32 identifiers — and decode their timestamp.
- htpasswd Generator Generate Apache and Nginx .htpasswd entries with bcrypt, APR1-MD5, or SHA-1 — entirely in your browser.
- Basic Auth Header Generator Build an HTTP Authorization: Basic header from a username and password (base64), and decode one back.
- X.509 Certificate Decoder Decode a PEM X.509 certificate locally — subject, issuer, validity, SANs, key, serial, and fingerprints — no upload.
- JWKS Generator Generate a JSON Web Key Set with a fresh RSA or EC key pair, a kid thumbprint, and the matching private key.
- JWK to PEM Converter Convert keys between JWK and PEM in both directions for RSA and EC, auto-detecting the input. Uses the browser Web Crypto API — keys never leave your machine.
- ECDSA Key Generator Generate an elliptic-curve (ECDSA) key pair — P-256, P-384 or P-521 — as PEM or JWK in your browser with Web Crypto. The private key never leaves your machine.
- JWT Secret Generator Generate a cryptographically strong random secret for HS256, HS384 or HS512 JWT signing, output as hex, base64 and base64url, sized to the algorithm.
- UUID v5 Generator Generate deterministic, name-based UUID v5 (SHA-1) identifiers from a namespace and a name. Built-in DNS, URL, OID and X.500 namespaces or your own.
- Snowflake ID Generator Generate Twitter/Discord-style 64-bit Snowflake IDs packing a millisecond timestamp, machine ID and sequence, with the bit breakdown and choice of epoch.
- ASN.1 / DER Decoder Decode ASN.1 DER structures — certificates, CSRs, keys, signatures — from PEM, base64 or hex into a readable tag/length/value tree with OIDs resolved to names.
- Diceware Passphrase Generator Generate strong, memorable Diceware-style passphrases from a built-in word list with a secure random source. Choose word count and separator and see the entropy.
- CSR Generator (Certificate Signing Request) Generate a PKCS#10 Certificate Signing Request and matching private key in your browser — RSA or ECDSA, full distinguished name and Subject Alternative Names (DNS and IP). WebCrypto, nothing uploaded.
- Self-Signed Certificate Generator Generate a self-signed X.509 certificate and private key in your browser — RSA or ECDSA, Subject Alternative Names, CA or server profile and the standard v3 extensions. WebCrypto, nothing uploaded.
- DKIM DNS Record Generator Generate the DNS TXT record for a DKIM public key — paste your selector and key, get the v=DKIM1 record split correctly for publishing.
- CSR Decoder Decode a PKCS#10 Certificate Signing Request in your browser — see the subject, key type and size, and the Subject Alternative Names. Nothing is uploaded.
- SRI Hash Generator Generate a Subresource Integrity (SRI) hash for a script or stylesheet — sha256/384/512 — so the browser blocks a tampered CDN file. Computed locally.
- PEM Viewer Decode a PEM block — certificate, key, CSR or CRL — and read its ASN.1 structure as a labelled tree. Base64 to DER parsed entirely in your browser.
- ASN.1 Viewer Decode ASN.1 DER or BER from PEM, base64 or hex and read the full tag/length/value tree with resolved OIDs and byte offsets. In your browser.
- CSR Viewer Decode a PKCS#10 certificate signing request and read its subject, public key, requested SANs and signature algorithm. Parsed in your browser — keys stay local.