BYTETOOLS

Security & Encryption Tools

Encrypt and decrypt text with AES, generate HMACs and file checksums, check password strength, validate card numbers and play with classic ciphers — all locally in your browser.

58 free tools

Password Strength Checker

Test how strong your password is with an entropy score, a strength meter, an estimated crack time and clear tips to make it harder to guess — all offline.

Passphrase Generator

Generate strong, memorable passphrases from random words using your browser's cryptographic RNG. Choose word count, separator, capitalization and a number suffix.

Random PIN Generator

Generate cryptographically secure random PIN codes from 4 to 12 digits. Create several at once and copy any PIN with a single click — all offline in your browser.

HMAC Generator

Generate an HMAC of any message with a secret key using HMAC-SHA1, SHA-256 or SHA-512 via the Web Crypto API. Output in hex or Base64, computed entirely offline.

AES Text Encrypter

Encrypt text with a password using AES-256-GCM and PBKDF2 in your browser. Get a single Base64 blob with the salt and IV embedded, ready to store or share safely.

AES Text Decrypter

Decrypt an AES-256-GCM Base64 blob back to plain text with the password used to encrypt it. Wrong passwords are detected and reported — decryption runs offline.

File Checksum Calculator

Calculate SHA-1, SHA-256 and SHA-512 checksums of any file in your browser. Copy each hash and compare against an expected value to verify a download is intact.

Hash Comparer

Compare two hashes or strings side by side to check they match. Get a normalized equality verdict plus per-character diff highlighting, all offline in your browser.

Secure Token Generator

Generate cryptographically secure random tokens for APIs, sessions and keys. Choose the length and a hex, base62 or base64url charset, and create several at once.

Credit Card Validator

Validate a credit card number with the Luhn algorithm and detect the brand (Visa, Mastercard, Amex, Discover and more) locally. Numbers are never sent anywhere.

Caesar Cipher Encoder & Decoder

Encode and decode text with the classic Caesar shift cipher, choose any shift from 1 to 25, and brute-force all 25 shifts to crack unknown messages.

ROT13 Encoder & Decoder

Encode and decode text with ROT13 instantly, add ROT5 for digits, or combine both as ROT18. A self-inverse cipher that hides spoilers and puzzle answers.

Atbash Cipher Encoder & Decoder

Encode and decode text with the Atbash cipher, an ancient mirror-alphabet substitution where A maps to Z. Self-inverse, preserves case and punctuation.

Vigenère Cipher Encoder & Decoder

Encode and decode text with the Vigenère polyalphabetic cipher using a keyword, with a live view of how the repeating key aligns to your message.

XOR Cipher Encoder & Decoder

XOR text against a repeating key and output the result as hex or Base64, then decode hex or Base64 back to text. Fast reversible obfuscation, not encryption.

Rail Fence Cipher Encoder & Decoder

Encode and decode text with the rail fence transposition cipher using 2 to 10 rails, with an optional zigzag visualization of the rail pattern.

NATO Phonetic Alphabet Converter

Convert text to the NATO phonetic alphabet (Alfa Bravo Charlie) and back, with spoken digits like Niner and names for punctuation. Free two-way converter.

Text to Hex Converter

Convert UTF-8 text to a hexadecimal byte string with a choice of separators — space, none, 0x or \x prefixes — and an uppercase toggle. Free text to hex tool.

Hex to Text Converter

Convert hexadecimal back to readable UTF-8 text, accepting hex with or without spaces, 0x or \x prefixes, with clear errors for odd-length or invalid input.

Keyboard Shift Cipher

Encode and decode text with the QWERTY keyboard shift cipher, replacing each key with the one to its left or right. Direction toggle and instant output.

RSA Key Pair Generator

Generate an RSA public and private key pair at 2048, 3072 or 4096 bits, exported as PEM and JWK. Created in your browser and never uploaded.

ECDSA Key Pair Generator

Generate an elliptic-curve key pair for ECDSA signing or ECDH key agreement over P-256, P-384 or P-521, exported as PEM and JWK, entirely in your browser.

JWT Signature Verifier

Verify a JSON Web Token's signature with a shared secret or PEM public key, and check its exp, nbf and iat claims against the clock — all in your browser.

TOTP Code Generator

Generate live TOTP two-factor codes from a Base32 secret with a countdown, previous and next windows, and a ready-made otpauth:// enrolment URI.

Htpasswd Generator

Create .htpasswd lines for Apache and Nginx basic auth using APR1-MD5 or {SHA}, with a random salt and a downloadable file. Hashed in your browser.

PBKDF2 Hash Generator

Derive a PBKDF2 key from a password with a chosen hash, salt and iteration count. Output in hex and Base64, computed locally with the Web Crypto API.

Hash Identifier

Paste a hash and find out what it probably is. Identifies MD5, SHA-1, SHA-256, NTLM, bcrypt, APR1 and more from length, character set and prefix.

CSP Header Generator

Build a Content-Security-Policy header directive by directive, with quick-add source tokens, nonce support and warnings for unsafe combinations.

NTLM Hash Generator

Generate the Windows NTLM hash of any password instantly. Computes MD4 over the UTF-16LE bytes locally, with the intermediate byte string shown.

SHA-384 Hash Generator

Generate a SHA-384 hash of any text or file in hex or Base64. Uses the Web Crypto API, so files are hashed locally and never uploaded anywhere.

Password Entropy Calculator

Measure a password's entropy in bits from its character pool and length, then see estimated crack times for five different attackers. Runs locally.

IBAN Validator

Validate one or many IBANs against the country length table and the ISO 7064 mod-97 checksum, with the reason for every failure and pretty formatting.

Playfair Cipher Encoder & Decoder

Encrypt and decrypt with the Playfair digraph cipher. Shows the 5×5 key square, the digraph splitting and which rule was applied to every pair.

SSL Certificate Decoder

Decode an SSL/TLS certificate to read its subject, issuer, validity dates, SANs, key size and SHA-256 fingerprint. Runs entirely in your browser.

CSR Decoder

Decode a PKCS#10 certificate signing request to verify the subject, key size and requested SANs before you send it to a certificate authority.

ASN.1 DER Decoder

Decode any DER or BER blob into a collapsible ASN.1 tree with tags, lengths, byte offsets and typed values including OIDs, times and integers.

PEM to DER Converter

Convert PEM to raw DER bytes or re-armour DER as PEM, with a hex dump, byte count and automatic detection of the structure you pasted.

JWK to PEM Converter

Convert a JSON Web Key to PEM using Web Crypto. Public keys export as SPKI and private keys as PKCS#8, ready for OpenSSL, Node.js, Go or Java.

PEM to JWK Converter

Convert a PEM public or private key to a JSON Web Key and compute its RFC 7638 thumbprint, all locally in your browser with Web Crypto.

SSH Key Fingerprint Generator

Generate the SHA-256 and MD5 fingerprints of an SSH public key, matching ssh-keygen exactly, with the key type and size read from the blob.

SRI Hash Generator

Generate a Subresource Integrity hash for any script or stylesheet and get a ready-to-paste integrity attribute with the crossorigin setting.

File Encryption Tool

Encrypt and decrypt any file locally with AES-256-GCM and a PBKDF2-derived passphrase key. Nothing is uploaded and no account is needed.

security.txt Generator

Build a valid RFC 9116 security.txt with Contact and Expires fields, URI validation and the optional Policy, Encryption and Canonical directives.

Security Header Analyzer

Paste HTTP response headers and get a per-header pass, warn or fail verdict plus an overall grade covering HSTS, CSP, cookies and information leaks.

Permissions-Policy Generator

Build a Permissions-Policy header from a checklist of browser features, with the matching iframe allow attribute and the legacy Feature-Policy form.

WPA PSK Generator

Derive the 256-bit WPA/WPA2 pre-shared key from an SSID and passphrase using PBKDF2-HMAC-SHA1 with 4096 iterations, exactly as IEEE 802.11i specifies.

MD4 Hash Generator

Generate an MD4 hash of any text or file in hex and Base64, with a UTF-16LE mode for NTLM password hashes. Runs entirely offline in your browser.

RIPEMD-160 Hash Generator

Compute the RIPEMD-160 digest of text or a file in hex and Base64, plus Bitcoin's HASH160 double hash. Everything runs locally in your browser.

SHA-3 Hash Generator

Generate SHA3-224, SHA3-256, SHA3-384, SHA3-512 or Ethereum's Keccak-256 hash of text or a file, in hex and Base64, entirely in your browser.

MySQL Password Hash Generator

Generate MySQL PASSWORD() and OLD_PASSWORD() hashes from any password, with ready-to-run SQL. Computed locally in your browser, never uploaded.

Django Password Hash Generator

Create a pbkdf2_sha256 password hash for Django with a random salt and your chosen iteration count, or verify a password against an existing hash.

IMEI Validator

Check whether an IMEI is valid with the Luhn algorithm, calculate a missing check digit, split out the TAC and serial, and validate a whole list at once.

VIN Validator & Decoder

Validate a 17-character VIN with the ISO 3779 check digit, and decode the world region, manufacturer prefix, model-year code and plant code.

Barcode Check Digit Calculator

Calculate or verify the GS1 check digit for EAN-13, EAN-8, UPC-A, UPC-E, GTIN-14, ITF-14 and SSCC-18, one code at a time or a whole pasted list.

ABA Routing Number Validator

Validate a 9-digit US bank routing number with the ABA checksum, calculate a missing ninth digit, and decode what the first two digits mean.

Enigma Machine Simulator

A working Enigma I / M3 simulator with rotors I–V, reflectors A, B and C, ring settings, start positions and a full plugboard. Runs in your browser.

Affine Cipher

Encrypt and decrypt with the affine cipher E(x) = (ax + b) mod 26, see the substitution alphabet, and brute-force all 312 keys to crack a message.

Polybius Square Cipher

Encode and decode with a Polybius square in 5×5 or 6×6 form, with an optional keyword, number or letter coordinates and the grid drawn out for you.