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Web Crypto Api fails to verify signature after converting from string

I am storing my data, including the signature in string format, and after converting the signature to and from strings following the MDN Documentation the verification process fails every time. The relevant code bits are:
const publicKey: CryptoKey = await window.crypto.subtle.importKey("spki", str2ab(window.atob(publicKeyStr)), { name: "RSA-PSS", hash: { name: "SHA-256" } }, false, ["verify"]);
const privateKey: CryptoKey = await window.crypto.subtle.importKey("pkcs8", str2ab(window.atob(privateKeyStr)), { name: "RSA-PSS", hash: { name: "SHA-256" } }, false, ["sign"])
if(privateKey && publicKey) {
try {
const sign = await window.crypto.subtle.sign({name: "RSA-PSS", saltLength: 32}, privateKey, encodedMessage);
const signature = window.btoa(String.fromCharCode.apply(null, [...new Uint8Array(sign)])); //the way said signature is stored and I can load it
const res = await window.crypto.subtle.verify({name: "RSA-PSS", saltLength: 32}, publicKey, str2ab(signature), encodedMessage);
console.log("Verifying:", signature, publicKey, res);
return res;
} catch (error) {
console.error(error);
return false;
}
}
return false;
With the str2ab(str) function being:
export function str2ab(str: string): ArrayBuffer {
const buf = new ArrayBuffer(str.length);
const bufView = new Uint8Array(buf);
for (let i = 0, strLen = str.length; i < strLen; i++) {
bufView[i] = str.charCodeAt(i);
}
return buf;
}
And encoded message is new TextEncoder.encode(messageString)

You store the Base64 encoded signature, but do not perform a Base64 decoding before verification, i.e. the Base64 decoding must be added. For this, in:
const res = await window.crypto.subtle.verify({name: "RSA-PSS", saltLength: 32}, publicKey, str2ab(signature), encodedMessage);
replace str2ab(signature) with b642ab(signature), where b642ab() performs the Base64 decoding:
(async () => {
var messageString = "The quick brown fox jumps over the lazy dog";
var encodedMessage = new TextEncoder().encode(messageString);
var publicKeyStr = "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAunF5aDa6HCfLMMI/MZLT5hDk304CU+ypFMFiBjowQdUMQKYHZ+fklB7GpLxCatxYJ/hZ7rjfHH3Klq20/Y1EbYDRopyTSfkrTzPzwsX4Ur/l25CtdQldhHCTMgwf/Ev/buBNobfzdZE+Dhdv5lQwKtjI43lDKvAi5kEet2TFwfJcJrBiRJeEcLfVgWTXGRQn7gngWKykUu5rS83eAU1xH9FLojQfyia89/EykiOO7/3UWwd+MATZ9HLjSx2/Lf3g2jr81eifEmYDlri/OZp4OhZu+0Bo1LXloCTe+vmIQ2YCX7EatUOuyQMt2Vwx4uV+d/A3DP6PtMGBKpF8St4iGwIDAQAB";
var privateKeyStr = "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";
const publicKey = await window.crypto.subtle.importKey("spki", str2ab(window.atob(publicKeyStr)), { name: "RSA-PSS", hash: { name: "SHA-256" } }, false, ["verify"]);
const privateKey = await window.crypto.subtle.importKey("pkcs8", str2ab(window.atob(privateKeyStr)), { name: "RSA-PSS", hash: { name: "SHA-256" } }, false, ["sign"]);
if(privateKey && publicKey) {
const sign = await window.crypto.subtle.sign({name: "RSA-PSS", saltLength: 32}, privateKey, encodedMessage);
const signature = window.btoa(String.fromCharCode.apply(null, [...new Uint8Array(sign)])); //the way said signature is stored and I can load it
const res = await window.crypto.subtle.verify({name: "RSA-PSS", saltLength: 32}, publicKey, b642ab(signature), encodedMessage);
console.log("Verifying:", /*signature, publicKey,*/ res);
}
})();
function b642ab(base64_string){
return Uint8Array.from(window.atob(base64_string), c => c.charCodeAt(0));
}
function str2ab(str) {
const buf = new ArrayBuffer(str.length);
const bufView = new Uint8Array(buf);
for (let i = 0, strLen = str.length; i < strLen; i++) {
bufView[i] = str.charCodeAt(i);
}
return buf;
}
After this bug is fixed, verification is successfully performed.

JS SubtleCrypto RSA Encrypt and Decrypt

So I am trying to implement some methods to encrypt then decrypt some data. I don't have any experience with this, and I've tried to follow along with some posts online on how to go about this.
When i pass the encrypted 'hello' into the decrypt function, i get this:
let a = importPublicKeyAndEncrypt('hello')
CryptoKey {type: "public", extractable: true, algorithm: {…}, usages: Array(1)} W29iamVjdCBBcnJheUJ1ZmZlcl0=
importPrivateKeyAndDecrypt(a)
Promise {<pending>}
DOMException: Failed to execute 'atob' on 'Window': The string to be decoded is not correctly encoded.
at importPrivateKeyAndDecrypt (<anonymous>:26:60)
The decrypt function works correctly when i use an encrypted messages from one of the posts i saw for PKCS#8 but not when i generate my own keys.
Here is the code
What am i doing wrong?
// PEM encoded X.509 key
const publicKey = `
-----BEGIN PUBLIC KEY-----
<removed for space>
-----END PUBLIC KEY-----`;
// PEM encoded PKCS#8 key
const privateKey = `
-----BEGIN PRIVATE KEY-----
<removed for space>
-----END PRIVATE KEY-----`;
async function importPublicKeyAndEncrypt(str) {
try {
const pub = await importPublicKey(publicKey);
console.log(pub);
const encrypted = await encryptRSA(pub, new TextEncoder().encode(str));
const encryptedBase64 = window.btoa(ab2str(encrypted));
console.log(encryptedBase64.replace(/(.{64})/g, '$1\n'));
} catch (error) {
console.log(error);
}
}
async function importPrivateKeyAndDecrypt(str) {
try {
const priv = await importPrivateKey(privateKey);
const decrypted = await decryptRSA(priv, str2ab(window.atob(str)));
console.log(decrypted);
} catch (error) {
console.log(error);
}
}
async function importPublicKey(spkiPem) {
return await window.crypto.subtle.importKey(
'spki',
getSpkiDer(spkiPem),
{
name: 'RSA-OAEP',
hash: 'SHA-256',
},
true,
['encrypt']
);
}
async function importPrivateKey(pkcs8Pem) {
return await window.crypto.subtle.importKey(
'pkcs8',
getPkcs8DerDecode(pkcs8Pem),
{
name: 'RSA-OAEP',
hash: 'SHA-256',
},
true,
['decrypt']
);
}
async function encryptRSA(key, plaintext) {
let encrypted = await window.crypto.subtle.encrypt(
{
name: 'RSA-OAEP',
},
key,
plaintext
);
return encrypted;
}
async function decryptRSA(key, ciphertext) {
let decrypted = await window.crypto.subtle.decrypt(
{
name: 'RSA-OAEP',
},
key,
ciphertext
);
return new TextDecoder().decode(decrypted);
}
function getSpkiDer(spkiPem) {
const pemHeader = '-----BEGIN PUBLIC KEY-----';
const pemFooter = '-----END PUBLIC KEY-----';
var pemContents = spkiPem.substring(
pemHeader.length,
spkiPem.length - pemFooter.length
);
var binaryDerString = window.atob(pemContents);
return str2ab(binaryDerString);
}
function getPkcs8DerDecode(pkcs8Pem) {
const pemHeader = '-----BEGIN PRIVATE KEY-----';
const pemFooter = '-----END PRIVATE KEY-----';
var pemContents = pkcs8Pem.substring(
pemHeader.length,
pkcs8Pem.length - pemFooter.length
);
var binaryDerString = window.atob(pemContents);
return str2ab(binaryDerString);
}
function str2ab(str) {
const buf = new ArrayBuffer(str.length);
const bufView = new Uint8Array(buf);
for (let i = 0, strLen = str.length; i < strLen; i++) {
bufView[i] = str.charCodeAt(i);
}
return buf;
}
function ab2str(buf) {
return String.fromCharCode.apply(null, new Uint8Array(buf));
}

There are only two minor flaws.
First, the return statements are missing in importPublicKeyAndEncrypt() and in importPrivateKeyAndDecrypt() (although the latter is not necessary for the current code snippet).
Also, it is necessary to wait for the promise of importPublicKeyAndEncrypt() before importPrivateKeyAndDecrypt() can be called.
With these fixes the code works:
// PEM encoded X.509 key
const publicKey = `-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAunF5aDa6HCfLMMI/MZLT
5hDk304CU+ypFMFiBjowQdUMQKYHZ+fklB7GpLxCatxYJ/hZ7rjfHH3Klq20/Y1E
bYDRopyTSfkrTzPzwsX4Ur/l25CtdQldhHCTMgwf/Ev/buBNobfzdZE+Dhdv5lQw
KtjI43lDKvAi5kEet2TFwfJcJrBiRJeEcLfVgWTXGRQn7gngWKykUu5rS83eAU1x
H9FLojQfyia89/EykiOO7/3UWwd+MATZ9HLjSx2/Lf3g2jr81eifEmYDlri/OZp4
OhZu+0Bo1LXloCTe+vmIQ2YCX7EatUOuyQMt2Vwx4uV+d/A3DP6PtMGBKpF8St4i
GwIDAQAB
-----END PUBLIC KEY-----`;
// PEM encoded PKCS#8 key
const privateKey = `-----BEGIN PRIVATE KEY-----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-----END PRIVATE KEY-----`;
async function importPublicKeyAndEncrypt(str) {
try {
const pub = await importPublicKey(publicKey);
//console.log(pub);
const encrypted = await encryptRSA(pub, new TextEncoder().encode(str));
const encryptedBase64 = window.btoa(ab2str(encrypted));
//console.log(encryptedBase64.replace(/(.{64})/g, '$1\n'));
return encryptedBase64;
} catch (error) {
console.log(error);
}
}
async function importPrivateKeyAndDecrypt(str) {
try {
const priv = await importPrivateKey(privateKey);
const decrypted = await decryptRSA(priv, str2ab(window.atob(str)));
//console.log(decrypted);
return decrypted;
} catch (error) {
console.log(error);
}
}
async function importPublicKey(spkiPem) {
return await window.crypto.subtle.importKey(
'spki',
getSpkiDer(spkiPem),
{
name: 'RSA-OAEP',
hash: 'SHA-256',
},
true,
['encrypt']
);
}
async function importPrivateKey(pkcs8Pem) {
return await window.crypto.subtle.importKey(
'pkcs8',
getPkcs8DerDecode(pkcs8Pem),
{
name: 'RSA-OAEP',
hash: 'SHA-256',
},
true,
['decrypt']
);
}
async function encryptRSA(key, plaintext) {
let encrypted = await window.crypto.subtle.encrypt(
{
name: 'RSA-OAEP',
},
key,
plaintext
);
return encrypted;
}
async function decryptRSA(key, ciphertext) {
let decrypted = await window.crypto.subtle.decrypt(
{
name: 'RSA-OAEP',
},
key,
ciphertext
);
return new TextDecoder().decode(decrypted);
}
function getSpkiDer(spkiPem) {
const pemHeader = '-----BEGIN PUBLIC KEY-----';
const pemFooter = '-----END PUBLIC KEY-----';
var pemContents = spkiPem.substring(
pemHeader.length,
spkiPem.length - pemFooter.length
);
var binaryDerString = window.atob(pemContents);
return str2ab(binaryDerString);
}
function getPkcs8DerDecode(pkcs8Pem) {
const pemHeader = '-----BEGIN PRIVATE KEY-----';
const pemFooter = '-----END PRIVATE KEY-----';
var pemContents = pkcs8Pem.substring(
pemHeader.length,
pkcs8Pem.length - pemFooter.length
);
var binaryDerString = window.atob(pemContents);
return str2ab(binaryDerString);
}
function str2ab(str) {
const buf = new ArrayBuffer(str.length);
const bufView = new Uint8Array(buf);
for (let i = 0, strLen = str.length; i < strLen; i++) {
bufView[i] = str.charCodeAt(i);
}
return buf;
}
function ab2str(buf) {
return String.fromCharCode.apply(null, new Uint8Array(buf));
}
(async () => {
let ciphertext = await importPublicKeyAndEncrypt('hello');
console.log("Ciphertext:\n", ciphertext.replace(/(.{48})/g, '$1\n'));
let decryptedData = await importPrivateKeyAndDecrypt(ciphertext);
console.log("Decrypted data:", decryptedData);
})();

I use jsencrypt
Client side:
const publicKey = `-----BEGIN PUBLIC KEY-----
keydatakeydata
-----END PUBLIC KEY-----`;
export function encrypt(text) {
let encrypt = new JSEncrypt();
encrypt.setPublicKey(publicKey);
let encrypted = encrypt.encrypt(text);
return encrypted.toString();
}
NodeJs
function decryptString(ciphertext) {
const privateKey = fs.readFileSync('./rsa_512_priv.pem').toString();
const decrypted = crypto.privateDecrypt({
key: privateKey,
padding: crypto.constants.RSA_PKCS1_PADDING
}, Buffer.from(ciphertext, 'base64'));
return decrypted.toString("utf8");
}
keys were generated with
openssl genrsa -out rsa_1024_priv.pem 1024
openssl rsa -pubout -in rsa_1024_priv.pem -out rsa_1024_pub.pem

RSA encryption with Java and decryption with JavaScript

I am trying to encrypt with Java (using javax.crypto.Cipher) and decrypt with JavaScript (using crypto.subtle). What I am doing is, I make the JavaScript side generate the key pair, then send the public key to the Java side by the following:
$(window).on("load", function () {
const enc = new TextEncoder();
const dec = new TextDecoder();
crypto.subtle.generateKey({
name: "RSA-OAEP",
modulusLength: 1024,
publicExponent: new Uint8Array([1, 0, 1]),
hash: "SHA-256"
},
true,
["encrypt", "decrypt"]
).then(function ({ privateKey, publicKey }) {
crypto.subtle.exportKey("spki", publicKey).then(function (spki) {
const strPublicKey = spkiToString(spki);
// SEND THE PUBLIC KEY TO THE SERVER (JAVA)
});
});
});
function spkiToString(keydata) {
var keydataS = arrayBufferToString(keydata);
return window.btoa(keydataS);
}
function arrayBufferToString(buffer) {
var binary = '';
var bytes = new Uint8Array(buffer);
var len = bytes.byteLength;
for (var i = 0; i < len; i++) {
binary += String.fromCharCode(bytes[i]);
}
return binary;
}
The server uses the public key for encryption:
try {
String publicKey = ""// this will come from the JS side
String message = "encrypt me"//
byte[] publicBytes = Base64.getDecoder().decode(publicKey).getBytes());
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(publicBytes);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PublicKey pubKey = keyFactory.generatePublic(keySpec);
Cipher cipher = Cipher.getInstance("RSA/ECB/OAEPPadding");
OAEPParameterSpec oaepParams = new OAEPParameterSpec("SHA-256", "MGF1", new MGF1ParameterSpec("SHA-256"),
PSource.PSpecified.DEFAULT);
cipher.init(Cipher.ENCRYPT_MODE, pubKey, oaepParams);
return Base64.getEncoder().encode(cipher.doFinal(message));
} catch (Exception e) {
e.printStacktrace();
}
return new byte[0];
The resulted value is then returned to the Javascript side, so it can decrypt the message:
const encryptedToken = "" // this will be obtained from the server
crypto.subtle.decrypt({
name: "RSA-OAEP",
hash: { name: "SHA-256" }
},
privateKey,
enc.encode(atob(encryptedToken))
).then(function (result) {
console.log("decrypted", dec.decode(result))
}).catch(function (e) {
console.log(e);
})
When the Javascript tries to decrypt, it throws a DOMException with no message (check the attached image).
What I am doing wrong? Thank you in advanced.

The problem is the enc.encode(atob(encryptedToken)) line in the decrypt() method of the last JavaScript code snippet. The UTF-8 encoding corrupts the data, preventing successful decryption. If this is changed, decryption works as shown in the following.
The JavaScript code below is essentially the same as the first code snippet from the question, with the addition of exporting the private key in PKCS8 format:
crypto.subtle.generateKey(
{
name: "RSA-OAEP",
modulusLength: 1024,
publicExponent: new Uint8Array([1, 0, 1]),
hash: "SHA-256"
},
true,
["encrypt", "decrypt"]
).then(function ({ privateKey, publicKey }) {
crypto.subtle.exportKey("spki", publicKey).then(function (spki) {
const strPublicKey = spkiToString(spki);
console.log(strPublicKey.replace(/(.{56})/g,'$1\n'));
crypto.subtle.exportKey("pkcs8", privateKey).then(function (pkcs8) {
const strPrivateKey = spkiToString(pkcs8);
console.log(strPrivateKey.replace(/(.{56})/g,'$1\n'));
});
});
});
function spkiToString(keydata) {
var keydataS = arrayBufferToString(keydata);
return window.btoa(keydataS);
}
function arrayBufferToString(buffer) {
var binary = '';
var bytes = new Uint8Array(buffer);
var len = bytes.byteLength;
for (var i = 0; i < len; i++) {
binary += String.fromCharCode(bytes[i]);
}
return binary;
}
This code was used to generate e.g. the following public key in X.509/SPKI format:
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC1F8+EvG9XP8jSXItV89QtlYy/5Z+arMegvMwsasS5IIUdr4b4eE2FGoDalaqyAxWOg/pBkzfBWAQkhuKz3i14OsBYQl1QDDm3yfmI498SsE7tZyrENCfTGrPwoCrQmEwTWOCfIBCh+mGRAUTgcsQO/g8pIFglF3QTTzlu3n0KhQIDAQAB
and private key in PKCS8 format:
MIICdwIBADANBgkqhkiG9w0BAQEFAASCAmEwggJdAgEAAoGBALUXz4S8b1c/yNJci1Xz1C2VjL/ln5qsx6C8zCxqxLkghR2vhvh4TYUagNqVqrIDFY6D+kGTN8FYBCSG4rPeLXg6wFhCXVAMObfJ+Yjj3xKwTu1nKsQ0J9Mas/CgKtCYTBNY4J8gEKH6YZEBROByxA7+DykgWCUXdBNPOW7efQqFAgMBAAECgYAK6oUFVNCHW15xI8f4ZerH1qh11tMgoUKlU0whb0wtdqLfj7mcl6/gkqDqzDPOaDYv8Y+vzT6CppoVU5YtznpCF4YRLuOfeAkY0kT9C7w62lu1C1aFMDS1Eydv0a10t001sp0W5U8J0LMgPpevPlksv2t9gZa08yGsBnVX9BIXjwJBAOrlsV6LsxNBnSKqXhZf1+uQe1vpPPzF3IXTvJzd4LhamcnImYayrg4Zjgj71+/0BFdWT9qGxtKGwJJGIjrMDG8CQQDFXLIrFMHVpdjrsAaQXvPWTSVIfVayi6Uib1HpXKiLJ53snebsBrBiShbAsJjrgWXzdurky6nGIlp5NV7i//pLAkEA4XaxRfe/XhdXtWNjxgQe41ueHH2GbXWZktbGrqcFwM4t2RHz0ueEy8HZpGPfQ9GrrQ0Kvs0o4AA5rO0mg9tBfwJBAJMWuaaH6spatyc4Yjv4uEuv5Sh4WUPp9WGLi4WbS/Whyf4N1It1lME8LGbhdqaWIrBnoTpxWw9SjREmqJgPZK8CQBAAI6IUkCeE+Lwub+akoBFuqyyIdIpIfXu4ntyxnZemmCNdotEfNL3yp0J3Rw6TpXyPDN/4uOrxt/aY2heXAKM=
The public key was applied in the Java code to generate the ciphertext below:
jCt9rD/6Q6OsjH+bd1XKB2FhDYTwzupQsFnwjKkrxulC3ztZx0j9/Zr6hBeCbFrdYFtxZi+j8lyyLJCHv0hpN0S5F/O6v/mhMIgCTWCmpWqcLqKC2zDWo180uL+dMysZm2JaBHzWA9VjnVTdVY3aRTWfu1fpEpTK6W9ESTVSS8Y=
The following JavaScript code is essentially the same as the 3rd code snippet extended by the import of the private key generated above. In addition, the ciphertext generated above is applied:
var pkcs8B64 = "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";
const pkcs8StrDER = atob(pkcs8B64);
const pkcs8DER = str2ab(pkcs8StrDER);
crypto.subtle.importKey(
"pkcs8",
pkcs8DER,
{
name: "RSA-OAEP",
modulusLength: 1024,
publicExponent: new Uint8Array([1, 0, 1]),
hash: "SHA-256",
},
true,
["decrypt"]
).then(function(privateKey){
const dec = new TextDecoder();
const encryptedToken = "jCt9rD/6Q6OsjH+bd1XKB2FhDYTwzupQsFnwjKkrxulC3ztZx0j9/Zr6hBeCbFrdYFtxZi+j8lyyLJCHv0hpN0S5F/O6v/mhMIgCTWCmpWqcLqKC2zDWo180uL+dMysZm2JaBHzWA9VjnVTdVY3aRTWfu1fpEpTK6W9ESTVSS8Y=";
crypto.subtle.decrypt(
{
name: "RSA-OAEP",
},
privateKey,
str2ab(atob(encryptedToken))
).then(function (result) {
console.log("decrypted:", dec.decode(result))
}).catch(function (e) {
console.log(e);
});
});
function str2ab(str) {
const buf = new ArrayBuffer(str.length);
const bufView = new Uint8Array(buf);
for (let i = 0, strLen = str.length; i < strLen; i++) {
bufView[i] = str.charCodeAt(i);
}
return buf;
}
Instead of the UTF-8 encoding which corrupts the data, the function str2ab() is used which converts the Base64 decoded data into an ArrayBuffer.
The substitution _base64ToArrayBuffer(encryptedToken) suggested in my comment is equally possible. Unlike str2ab(), _base64ToArrayBuffer() also performs the base64 decoding.
Running the code results in the plaintext encrypt me of the Java code.

Decrypt an RSA message from browser with window.crypto.subtle APIs

I'm trying to decode an RSA 2048 bit message encoded with a public key using the corresponding private key. The environment is google chrome and I'm using the window.crypto.subtle APIs.
I generated the key couple and encoded the message using openssl tools:
# generate keys and put the private one in file private_key.pem
openssl genpkey -algorithm RSA -out private_key.pem -pkeyopt rsa_keygen_bits:2048
# extract public key in file public_key.pem
openssl rsa -pubout -in private_key.pem -out public_key.pem
# encode message input.txt using the public key
openssl rsautl -encrypt -oaep -inkey public_key.pem -pubin -in input.txt -out msg_rsa.enc
# convert the encoded msg in base 64 format
base64 msg_rsa.enc > msg_rsa_64.enc
This is the javascript code I'm using to decode the message:
function str2ab(str) {
const buf = new ArrayBuffer(str.length);
const bufView = new Uint8Array(buf);
for (let i = 0, strLen = str.length; i < strLen; i++) {
bufView[i] = str.charCodeAt(i);
}
return buf;
}
async function importPrivateKey(pem) {
pem = pem.replace( /[\r\n]+/gm, "" );
// fetch the part of the PEM string between header and footer
const pemHeader = "-----BEGIN PRIVATE KEY-----";
const pemFooter = "-----END PRIVATE KEY-----";
const pemContents = pem.substring(pemHeader.length, pem.length - pemFooter.length);
// base64 decode the string to get the binary data
const binaryDerString = window.atob(pemContents);
// convert from a binary string to an ArrayBuffer
const binaryDer = str2ab(binaryDerString);
return window.crypto.subtle.importKey(
"pkcs8",
binaryDer,
{
name: "RSA-OAEP",
modulusLength: 2048,
publicExponent: new Uint8Array([1, 0, 1]),
hash: "SHA-256",
},
true,
["decrypt"]
);
}
async function decryptRSA(_key, ciphertext) {
let decrypted = await window.crypto.subtle.decrypt(
{
name: "RSA-OAEP"
},
_key,
ciphertext
);
const dec = new TextDecoder();
return dec.decode(decrypted);
}
const fromBase64 = base64String => Uint8Array.from(atob(base64String), c => c.charCodeAt(0));
window.onload = init;
async function init() {
const privateKey = '-----BEGIN PRIVATE KEY-----\
MIIEvwIBADANBgkqhkiG9w0BAQEFAASCBKkwggSlAgEAAoIBAQC3jmTi3O1k2YXs\
AM6nNTTIzDq5YWkxYrYb6cpO9eYuzmphgRnVDR6a1YWRXMoCuCfuNXcDGywzudRn\
bBMw0FHKLUqCttVHGpZYu0+0tRR10ubxiz/xnd/aCmRYHcmUNn8Qdh3KU59A9HK5\
HhYFf1vhK8r3fkoO4CjoGo1ROzXyMybUSy+4mSNscUtt5LwrVn48vXvG5i5B4DRT\
nM4cINmutEzA2s5cDt+dzU4Py71fKBRDRIGGn0vdVSoZKbWuhm5WewyRewCk7HFc\
PALCi5/1A7VKDAHUC4FlXmuG2+wzdchEyxMj6oLR7+BkKFQaTmuMM/22cGBjVTVt\
pSr3iDovAgMBAAECggEBAIuTQW+oovNu3IDq1DkdIjgV5AmW4tBkySlMi0OjhBbP\
auEdtDDnOwBtoJU6Q3nx4psmGItKHEBw6+yAp88UeT0NV30x3delhfGO7Trx/s7h\
Qi8lvcfSTqeUA11luSR0lAZGaryw/YX820eccw5XG9yK2ll7tIC/PxvPJOpB5fF2\
XGxGrionTjHDzXJ1OWX0i0aZlNNufInJAHhlt7aT3GiQMKcQs+AUb/+bWxI3Hln8\
KcL13EUlD4pJW8vtTK3gCnQNKKMoPB5Ugqe5BrU8ElkBz+zSKDnVwt5bgjrlucYz\
rKJxWr6/qTRZkzmvkhaJeNzzepfwkFsQ/eHcxYrtuDECgYEA8OXkQ2SqYDZwizCd\
SuVkx2zHm3zXYRSlRtnXYoUdJyTyuZ4k2GvXBrlwRsOJ14emVkHKyR5enmNjwrW5\
dcD2tbBzavcqOYAMiHcKklcS/gWgPx0X5QFHU33vr8u51BQWCz75lxddWNKxVAN/\
cUTugONtS4+EP4dSZhuxHt6RscsCgYEAwxA9QmZrI54hjMkIyqwmviRmIk42S5kk\
OxbhxBbt5qVueLRB092JyGmCR2kYiqdHCYkGFDOE4kni6Bsszq5CSJvhiATFeZeX\
ldFQeZqAiRY2rAd7xD1upMug/cK3ODA8k3k/e72CtyxtBTR01q29SnPx5p/57MrI\
3ogddHlGvK0CgYEA3VqhELwjQh1D9OJK5lM683SlRd7FGdOauyvYmhKu4xU0ZBNI\
0ATnpKoo3R04P+/JjGEQMRXS4794H6ZUMDuLdxAYPiW3ivZ6jbq04BtavEf3I4dc\
OXWfULzbzbFpo9KBHvxS4974S3Hut8AvDqnEbnKML25EmwuBT4oKis8BGVkCgYEA\
nusPDZbFeNou+TUbzYrdcZHUB+TyhTq58s4clxYbMgrbaslozAQ0aavT8Pvle6j2\
zgTth+3FOFr72x+wrJ358I/W+Wrxu7NOU0eZqci/KXCIkDT0l5d5GhewDK3jeYqK\
/5cLqnNmGHfARjpLak9X5V162erBwjIf3nTEkozvnW0CgYB6L1CX3DkTFH3OBcJe\
SvV18RDUfNI8MpUKcpofmwwvgER3GrehSZHRVxVwNbnJOqbh/oiwmmNJieKrFsk9\
EzCRBVWdZByHHYW2js+gCrAp+ghnl1QEAeCU7YTxCJ2fZIAmfB9X4u/7ARtVxnZY\
mOWlm65KUYr5lf2Ws5plL4pCRA==\
-----END PRIVATE KEY-----';
const ciphertext = 'F6/NwENdUZSl+vrgpWVkyWPQuYaTGDNZPIvj4KmIRHVx4qybxN24LPIgk0Rl84KHcLFadZWCjNpM\
vg3l826OaKZAtwvIp9IxVrMbvtNOymY6A1koKvC9ema92SR4DC9hmTtMxhUB6r3XgACtRLFqMfg+\
zYSHfFqQEGJg3yZ43hfzIq/gCfHPk5sZXASq5WY5b9yd4gRonn5D4OCD6xna/r5ovHfrpO/Fwe8N\
eeY2gqTAdtzvtmOw/HLQhGANejpJYr1IriQbepM7jLjBkJX+uCn38O1MxpQb7s5RXTvGvoEoofWV\
Cq8gNFhgnVFuurdZUiY0bn58UwaVFdwzEfDSUQ==';
try {
const key = await importPrivateKey(privateKey);
const decoded = await decryptRSA(key, fromBase64(ciphertext));
console.log(decoded);
} catch(error) {
console.log(error);
}
}
Running the code, I got an exception in window.crypto.subtle.decrypt with the rather useless message "DOMException".
What am I doing wrong?
Thanks

There's only one flaw: The posted code currently uses OAEP with SHA256. The ciphertext can be decrypted with the posted key if OAEP with SHA1 is applied as padding.
In addition, the function fromBase64 can be used to Base64 decode the key into a TypedArray, so the function str2ab is actually not needed (but of course this is not an error, just redundant).
const fromBase64 = base64String => Uint8Array.from(atob(base64String), c => c.charCodeAt(0));
const getPkcs8Der = pkcs8Pem => {
pkcs8Pem = pkcs8Pem.replace( /[\r\n]+/gm, "" );
const pkcs8PemHeader = "-----BEGIN PRIVATE KEY-----";
const pkcs8PemFooter = "-----END PRIVATE KEY-----";
pkcs8Pem = pkcs8Pem.substring(pkcs8PemHeader.length, pkcs8Pem.length - pkcs8PemFooter.length);
return fromBase64(pkcs8Pem);
}
async function importPrivateKey(pkcs8Pem) {
return await window.crypto.subtle.importKey(
"pkcs8",
getPkcs8Der(pkcs8Pem),
{
name: "RSA-OAEP",
hash: "SHA-1", // Replace SHA-256 with SHA-1
},
true,
["decrypt"]
);
}
async function decryptRSA(key, ciphertext) {
let decrypted = await window.crypto.subtle.decrypt(
{
name: "RSA-OAEP"
},
key,
ciphertext
);
const dec = new TextDecoder();
return dec.decode(decrypted);
}
window.onload = init;
async function init() {
const privateKey =
'-----BEGIN PRIVATE KEY-----\
MIIEvwIBADANBgkqhkiG9w0BAQEFAASCBKkwggSlAgEAAoIBAQC3jmTi3O1k2YXs\
AM6nNTTIzDq5YWkxYrYb6cpO9eYuzmphgRnVDR6a1YWRXMoCuCfuNXcDGywzudRn\
bBMw0FHKLUqCttVHGpZYu0+0tRR10ubxiz/xnd/aCmRYHcmUNn8Qdh3KU59A9HK5\
HhYFf1vhK8r3fkoO4CjoGo1ROzXyMybUSy+4mSNscUtt5LwrVn48vXvG5i5B4DRT\
nM4cINmutEzA2s5cDt+dzU4Py71fKBRDRIGGn0vdVSoZKbWuhm5WewyRewCk7HFc\
PALCi5/1A7VKDAHUC4FlXmuG2+wzdchEyxMj6oLR7+BkKFQaTmuMM/22cGBjVTVt\
pSr3iDovAgMBAAECggEBAIuTQW+oovNu3IDq1DkdIjgV5AmW4tBkySlMi0OjhBbP\
auEdtDDnOwBtoJU6Q3nx4psmGItKHEBw6+yAp88UeT0NV30x3delhfGO7Trx/s7h\
Qi8lvcfSTqeUA11luSR0lAZGaryw/YX820eccw5XG9yK2ll7tIC/PxvPJOpB5fF2\
XGxGrionTjHDzXJ1OWX0i0aZlNNufInJAHhlt7aT3GiQMKcQs+AUb/+bWxI3Hln8\
KcL13EUlD4pJW8vtTK3gCnQNKKMoPB5Ugqe5BrU8ElkBz+zSKDnVwt5bgjrlucYz\
rKJxWr6/qTRZkzmvkhaJeNzzepfwkFsQ/eHcxYrtuDECgYEA8OXkQ2SqYDZwizCd\
SuVkx2zHm3zXYRSlRtnXYoUdJyTyuZ4k2GvXBrlwRsOJ14emVkHKyR5enmNjwrW5\
dcD2tbBzavcqOYAMiHcKklcS/gWgPx0X5QFHU33vr8u51BQWCz75lxddWNKxVAN/\
cUTugONtS4+EP4dSZhuxHt6RscsCgYEAwxA9QmZrI54hjMkIyqwmviRmIk42S5kk\
OxbhxBbt5qVueLRB092JyGmCR2kYiqdHCYkGFDOE4kni6Bsszq5CSJvhiATFeZeX\
ldFQeZqAiRY2rAd7xD1upMug/cK3ODA8k3k/e72CtyxtBTR01q29SnPx5p/57MrI\
3ogddHlGvK0CgYEA3VqhELwjQh1D9OJK5lM683SlRd7FGdOauyvYmhKu4xU0ZBNI\
0ATnpKoo3R04P+/JjGEQMRXS4794H6ZUMDuLdxAYPiW3ivZ6jbq04BtavEf3I4dc\
OXWfULzbzbFpo9KBHvxS4974S3Hut8AvDqnEbnKML25EmwuBT4oKis8BGVkCgYEA\
nusPDZbFeNou+TUbzYrdcZHUB+TyhTq58s4clxYbMgrbaslozAQ0aavT8Pvle6j2\
zgTth+3FOFr72x+wrJ358I/W+Wrxu7NOU0eZqci/KXCIkDT0l5d5GhewDK3jeYqK\
/5cLqnNmGHfARjpLak9X5V162erBwjIf3nTEkozvnW0CgYB6L1CX3DkTFH3OBcJe\
SvV18RDUfNI8MpUKcpofmwwvgER3GrehSZHRVxVwNbnJOqbh/oiwmmNJieKrFsk9\
EzCRBVWdZByHHYW2js+gCrAp+ghnl1QEAeCU7YTxCJ2fZIAmfB9X4u/7ARtVxnZY\
mOWlm65KUYr5lf2Ws5plL4pCRA==\
-----END PRIVATE KEY-----';
const ciphertext =
'F6/NwENdUZSl+vrgpWVkyWPQuYaTGDNZPIvj4KmIRHVx4qybxN24LPIgk0Rl84KHcLFadZWCjNpM\
vg3l826OaKZAtwvIp9IxVrMbvtNOymY6A1koKvC9ema92SR4DC9hmTtMxhUB6r3XgACtRLFqMfg+\
zYSHfFqQEGJg3yZ43hfzIq/gCfHPk5sZXASq5WY5b9yd4gRonn5D4OCD6xna/r5ovHfrpO/Fwe8N\
eeY2gqTAdtzvtmOw/HLQhGANejpJYr1IriQbepM7jLjBkJX+uCn38O1MxpQb7s5RXTvGvoEoofWV\
Cq8gNFhgnVFuurdZUiY0bn58UwaVFdwzEfDSUQ==';
try {
const key = await importPrivateKey(privateKey);
const decrypted = await decryptRSA(key, fromBase64(ciphertext));
console.log(decrypted);
} catch(error) {
console.log(error);
}
}

Using node-jose, how do I decrypt the data I just encrypted?

I am trying to implement simple JOSE encrypt and decrypt functions using node-jose.
My code is as follows (written using Node 8.2.1)
const { JWE } = require('node-jose');
const jose = (publicKey, privateKey) => {
async function encrypt(raw) {
if (!raw) throw new Error('Missing raw data.')
const buffer = new Buffer(JSON.stringify(raw));
return JWE.createEncrypt(publicKey).update(buffer).final();
}
async function decrypt(encrypted) {
if (!encrypted) throw new Error('Missing encrypted data.')
const buffer = new Buffer(JSON.stringify(encrypted));
return JWE.createDecrypt(privateKey).decrypt(buffer);
}
return { encrypt, decrypt }
}
module.exports = jose;
I generate an RSA keypair using generate-rsa-keypair.
So testing via this code the encryption side of things works fine
const { JWK } = require('node-jose');
const keygen = require('generate-rsa-keypair');
const jose = require('./src/utils/jose');
const rawKeys = keygen();
const makeKey = pem => JWK.asKey(pem, 'pem');
async function start() {
const publicKey = await makeKey(rawKeys.public)
const privateKey = await makeKey(rawKeys.private)
const raw = {
iss: 'test',
exp: new Date().getTime() + 3600,
sub: {
test: 'This is a test',
},
};
const { encrypt, decrypt } = jose(publicKey, privateKey);
return encrypt(raw).then(encrypted => decrypt(encrypted));
}
return start().then((result) => {
console.log('decrypted', result)
}, (err) => {
console.error(err);
});
the encrypted result is
{
recipients: [ { encrypted_key: 'ciNiK6Unq30zCAXxIl2Dx9b8bZAi79qbpL1yUCwTFnSghFLrIZ11_D2ozt5on3r3ThUu96oDLZPcNShbqWPMV49NvQAsSNGdemhgzmTt3Lf3rJn1YiqvJvqf5NIXdmzjdoEZi-d9224mGpZGVKtIIFeT6-0hYgm5zNqq_aF_X2jy5IiF-mAGspNdXIk_KXPrTVbnU-XL9J5aAoG2Lp51Te1WzGA4Fjg4Ve5ZTzH6TLlQ5R5Ob_14liK-INrSi3armwXrtMgJcTmI_4oBtORtZp8AjaXzecFO_GzifvRVCSKx2vmpy9KaECpskMhZBHVx9RX9cvGKh7hq3Y7vsUucZw' } ],
protected: 'eyJhbGciOiJSU0EtT0FFUCIsImtpZCI6IldLWS1ONDRXM2RnanA4U2ZxSlp3TldqV3AzUG1XZ29UczhjRDh3eWNSUWciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0',
iv: 'wvqir2ewtQPfDHQtzl6IUg',
ciphertext: 'ZwIrL_3739LI17rh3gWDUA6lXIL7ewkSh54FO_RwumC0qh9B0DcAr8RyXsfPbW19cV4u7SbZNSRP6B8qNOTy-2iENlqBISfE_kolDt8g5sg',
tag: 'z8nwrJfRgOi1hYMBI9lGeQ'
}
but when I try to decrypt that I get
Error: no key found
at processKey (node_modules/node-jose/lib/jwe/decrypt.js:157:22)
There are very few examples of using node-jose so I am unsure of the following
I am assuming I ought to be decrypting with the private key. But that's just an assumption. None of the examples show use of public/private key pairs, just a single key.
I'm assuming that the results of the encryption can just be strringified and turned into a buffer and passed into decrypt but perhaps that's not the case.
How does this really work?

When using public/private key pairs, the private key is used to decrypt and the public key is used to encrypt.
The input to JWEDecrypter.decrypt() is the promised output from JWEEncrypter.final().
Change your decrypt function to:
async function decrypt(encrypted) {
if (!encrypted) throw new Error('Missing encrypted data.')
return JWE.createDecrypt(privateKey).decrypt(encrypted);
}