Crypto tools 58
Encrypt, decrypt, sign, verify, hash and derive keys with Web Crypto in your browser. Keys are generated in the page and never leave it. The classical ciphers here are puzzle tools with no security value, and each one says so on its own page.
Encrypt & decrypt6
n→nAES-GCM encryptEncrypt a file with AES-256-GCM under a password.Runs on each file you dropn→nAES-GCM decryptDecrypt a file produced by AES-GCM encrypt.Runs on each file you dropn→nAES key wrap (RFC 3394)Wrap a raw key under a key-encrypting key (AES-KW).Runs on each file you dropn→nAES key unwrap (RFC 3394)Unwrap a key that was wrapped with AES-KW.Runs on each file you dropn→nRSA-OAEP encryptEncrypt a small file with an RSA public key (RSA-OAEP).Runs on each file you dropn→nRSA-OAEP decryptDecrypt a file produced by RSA-OAEP encrypt, with the matching private key.Runs on each file you drop
Keys & signatures6
·→1RSA key pair generateGenerate an RSA key pair, on your device; the private key never leaves your browser.Takes no filen→nRSA-PSS signSign a file with an RSA private key (RSA-PSS/SHA-256).Runs on each file you dropn→nRSA-PSS verifyCheck a file against an RSA signature (RSA-PSS/SHA-256).Runs on each file you drop·→1ECDSA key pair generateGenerate an ECDSA key pair, on your device; the private key never leaves your browser.Takes no filen→nECDSA signSign a file with an ECDSA private key.Runs on each file you dropn→nECDSA verifyCheck a file against an ECDSA signature.Runs on each file you drop
Password hashing7
·→1Argon2id hashHash a password with Argon2id, on your device. For password storage, not for hashing files.Takes no file·→1Argon2 verifyCheck a password against an Argon2 hash.Takes no file·→1bcrypt hashHash a password with bcrypt, on your device. For password storage, not for hashing files.Takes no file·→1bcrypt verifyCheck a password against a bcrypt hash.Takes no file·→1scrypt deriveDerive a key from a password with scrypt.Takes no file·→1PBKDF2 deriveDerive a key from a password with PBKDF2.Takes no file·→1HKDF deriveDerive a key from input keying material with HKDF.Takes no file
One-time codes2
Hashes & checksums11
1→1Generate all hashesCompute every hash-wasm digest of a file in one pass, on your device. (MurmurHash3 and the Fletcher checksums have their own dedicated tools.)Takes one filen→nHMACCompute an HMAC of a file with a key.Runs on each file you dropn→nMD4 hashCompute an MD4 digest of a file, on your device. MD4 is cryptographically broken, useful only for legacy or forensic work, not integrity or security.Runs on each file you drop·→1NT hashCompute a Windows NT hash (MD4 of UTF-16LE) from a password, on your device. Unsalted and trivially cracked, this is a forensics tool, not a way to protect anything.Takes no filen→nMurmurHash3 (32-bit)Compute a MurmurHash3 (x86, 32-bit) digest, a fast non-cryptographic hash, not for security.Runs on each file you dropn→nFletcher-8 checksumFletcher-8 checksum. A fast error-detection checksum, not a cryptographic hash. No authoritative spec exists for this word size (unlike -16/-32/-64): this implementation sums 4-bit nibbles mod 15, low nibble then high nibble per byte. A different convention (whole bytes mod 15) gives a different digest. Check your other tool uses the same convention before comparing.Runs on each file you dropn→nFletcher-16 checksumFletcher-16 checksum. A fast error-detection checksum, not a cryptographic hash.Runs on each file you dropn→nFletcher-32 checksumFletcher-32 checksum. A fast error-detection checksum, not a cryptographic hash.Runs on each file you dropn→nFletcher-64 checksumFletcher-64 checksum. A fast error-detection checksum, not a cryptographic hash.Runs on each file you dropn→nLuhn checksumValidate a number against the Luhn checksum, or compute its check digit. Used by credit card and ID numbers.Runs on each file you dropn→nAnalyse hashGuess which algorithm(s) produced a hash, from its length and charset. A heuristic, not a proof.Runs on each file you drop
Classical ciphers26
n→nCaesar encodeCaesar encode. A classical cipher, computed on your device.Runs on each file you dropn→nCaesar decodeCaesar decode. A classical cipher, computed on your device.Runs on each file you dropn→nCaesar brute forceCaesar brute force, classical cipher, a puzzle not a protection, computed on your device.Runs on each file you dropn→nCaesar Box encodeCaesar Box encode, classical cipher, a puzzle not a protection, computed on your device. Not reversible to the exact input: the text is padded with X to fill the next perfect square, and the padding is indistinguishable from real text afterwards. "HELLO WORLD" decodes back as "HELLO WORLDXXXXX".Runs on each file you dropn→nCaesar Box decodeCaesar Box decode, classical cipher, a puzzle not a protection, computed on your device. The X padding the encoder added to reach a perfect square cannot be told from real text and is returned with the plaintext. Expect trailing X characters that were not in the original.Runs on each file you dropn→nVigenère encodeVigenère encode. A classical cipher, computed on your device.Runs on each file you dropn→nVigenère decodeVigenère decode. A classical cipher, computed on your device.Runs on each file you dropn→nSubstitution cipher encodeSubstitution cipher encode, classical cipher, a puzzle not a protection, computed on your device.Runs on each file you dropn→nSubstitution cipher decodeSubstitution cipher decode, classical cipher, a puzzle not a protection, computed on your device.Runs on each file you dropn→nAffine cipher encodeAffine cipher encode, classical cipher, a puzzle not a protection, computed on your device.Runs on each file you dropn→nAffine cipher decodeAffine cipher decode, classical cipher, a puzzle not a protection, computed on your device.Runs on each file you dropn→nBifid cipher encodeBifid cipher encode, classical cipher, a puzzle not a protection, computed on your device. Not reversible to the exact input: the classic 5x5 Polybius square has no J, so J is folded into I, and everything that is not a letter, including spaces, digits and punctuation, is dropped. Output is uppercase. "The fox jumps, 42 times!" comes back as "THEFOXIUMPSTIMES".Runs on each file you dropn→nBifid cipher decodeBifid cipher decode, classical cipher, a puzzle not a protection, computed on your device. Not reversible to the exact input: J was folded into I at encode time and all spacing, digits and punctuation were dropped, so plaintext comes back as uppercase letters only.Runs on each file you dropn→nRail Fence encodeRail Fence encode, classical cipher, a puzzle not a protection, computed on your device.Runs on each file you dropn→nRail Fence decodeRail Fence decode, classical cipher, a puzzle not a protection, computed on your device.Runs on each file you dropn→nBaconian cipher encodeBaconian cipher encode, classical cipher, a puzzle not a protection, computed on your device. Non-letters pass through this direction, but they carry no information and the decoder drops them: a round trip returns lowercase letters only, so "The fox jumps, 42 times!" comes back as "thefoxjumpstimes".Runs on each file you dropn→nBaconian cipher decodeBaconian cipher decode, classical cipher, a puzzle not a protection, computed on your device. Only the A/B letters carry information, so every space, digit and punctuation mark in the ciphertext is dropped and the plaintext comes back lowercase, letters only.Runs on each file you dropn→nAtbash cipherAtbash cipher. A classical cipher, computed on your device.Runs on each file you dropn→nA1Z26 encodeA1Z26 encode. A classical cipher, computed on your device.Runs on each file you dropn→nROT5 (digits)ROT5 (digits). A classical cipher, computed on your device.Runs on each file you dropn→nROT13ROT13. A classical cipher, computed on your device.Runs on each file you dropn→nROT47ROT47, classical cipher, a puzzle not a protection, computed on your device.Runs on each file you dropn→nLeetspeakLeetspeak. A classical cipher, computed on your device.Runs on each file you dropn→nReverse textReverse text. A classical cipher, computed on your device.Runs on each file you dropn→nXOR cipherXOR cipher, classical cipher, a puzzle not a protection, computed on your device.Runs on each file you dropn→nXOR brute force (single-byte key)XOR brute force (single-byte key), classical cipher, a puzzle not a protection, computed on your device.Runs on each file you drop
Questions
Where do my keys go?
Nowhere. Keys are generated by Web Crypto inside this tab and stay in page memory. Nothing is transmitted, and nothing is stored after you close it. Save the key yourself if you need it again, because this site cannot give it back to you.
Is browser crypto safe to rely on?
The algorithms are the browser's own Web Crypto implementation, the same one used by HTTPS in that browser. The weak point is the environment: a compromised machine or a hostile extension sees what the page sees. For high-value keys, use dedicated offline tooling.
What can I decrypt a file with?
The matching tool on this site. AES-GCM decrypt reads what AES-GCM encrypt produced, RSA-OAEP decrypt reads what RSA-OAEP encrypt produced. Each tool page names its pair, and the format is the standard one, so other implementations of the same algorithm can read it too.
Are the classical ciphers secure?
No, and every one of them says so on its own page. Caesar, Vigenere, Bifid, substitution, XOR with a repeating key and the rest are puzzle tools. They are here for CTFs and teaching. Use AES-GCM encrypt for anything real.
Which password hash should I use?
Argon2 for new work, with bcrypt and scrypt available where an existing system needs them. Plain hashes like MD5 or SHA-256 are the wrong tool for passwords, no matter how many times you apply them, because they are built to be fast.