XOR with crypto’s randomBytes

I want to create a master key where I XOR 3 random keys (generated with crypto.randomBytes).

A,B,C = crypto.randomBytes(32)
MASTER_KEY = A ^ B ^ C;

JavaScript
​x
 
A,B,C = crypto.randomBytes(32)
MASTER_KEY = A ^ B ^ C;
​

I am not sure how to make this work in Javascript. randomBytes returns a Buffer. I’m not sure if I have to do a .toString() on it or just perform the XOR as a Buffer?

Answer

This should do:

const BUF_LEN = 32
const result = Buffer.alloc(BUF_LEN)

for (let i = 0; i < BUF_LEN; i++) {
  const [a, b, c] = [A.readUInt8(i), B.readUInt8(i), C.readUInt8(i)]
  result.writeUInt8(a ^ b ^ c, i)
}

console.log(result.toString('hex'))

JavaScript
 
const BUF_LEN = 32
const result = Buffer.alloc(BUF_LEN)
​
for (let i = 0; i < BUF_LEN; i++) {
  const [a, b, c] = [A.readUInt8(i), B.readUInt8(i), C.readUInt8(i)]
  result.writeUInt8(a ^ b ^ c, i)
}
​
console.log(result.toString('hex'))
​

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Answer