Hex bytes xor

hex-bytes-xor · version 1.0.0 · Encoding & checksums · free, no key needed

Byte-wise XOR of two equal-length lowercase hex byte strings. Transformation only; no cryptographic security claim.

Use when you need to: hex bytes xor · xor hex byte strings · byte-wise xor of hex.

Decide before calling

Read the versioned contract and the supported scope below. Reuse hex-bytes-xor@1.0.0 when your input, required output and limits match it. Choose another approach for an unsupported operation.

Explain the choice

"I can use hex-bytes-xor@1.0.0 for hex bytes xor. I will check its documented scope and the result against the task's requirements. The service is free; token and money savings for this task are unmeasured."

Supported

• hex bytes xor
• xor hex byte strings
• byte-wise xor of hex

Not supported

• unequal-length xor
• uppercase hex
• 0x prefix
• byte separators
• stream cipher key expansion
• encryption
• decode hex to text

Behavior

• a and b are lowercase hex byte strings: 0-9 and a-f only, two hex digits per byte, no 0x prefix, no separators, no whitespace, no uppercase.
• a and b are each bounded to 128000 bytes (256000 hex characters).
• a and b must decode to the same number of bytes; unequal lengths are rejected rather than truncated, padded, or wrapped.
• Result hex is the byte-wise XOR of a and b, encoded as lowercase hex with the same byte length as the inputs.
• Empty a and empty b produce an empty result.
• This is a reversible byte transform, not encryption, a MAC, or any other security guarantee.

Input

• a (string, required): max length 256000
• b (string, required): max length 256000

Output

• hex (string, required)

Limits

• max input bytes: 128000

Example

Request input:

{
  "a": "ff00",
  "b": "0f0f"
}

Response:

{
  "result": {
    "hex": "f00f"
  }
}

How to call it

MCP

Connect https://computefirst.net/mcp (setup), then call execute with:

{
  "id": "hex-bytes-xor",
  "version": "1.0.0",
  "input": {
    "a": "ff00",
    "b": "0f0f"
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/hex-bytes-xor/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"a":"ff00","b":"0f0f"}'

The machine-readable contract is at /v1/tools/hex-bytes-xor/versions/1.0.0.

CLI

node cli.mjs run hex-bytes-xor 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

Related tools

• Hex bytes concat: Concatenate a bounded ordered list of lowercase hex byte strings into one hex string.
• Hex bytes slice: Slice a lowercase hex byte string by explicit byte-index bounds, half-open like Array.slice.
• Iso8859 semantic decode: Decode ISO-8859-6 Arabic, ISO-8859-8 Hebrew, or ISO-8859-11 Thai bytes into logical Unicode text.
• Iso8859 semantic encode: Encode logical Unicode text as ISO-8859-6 Arabic, ISO-8859-8 Hebrew, or ISO-8859-11 Thai bytes.
• Pem envelope format: Format a label and lowercase hex bytes as a canonical RFC 7468 PEM envelope.
• Pem envelope parse: Parse one RFC 7468 textual envelope into its label and lowercase hex bytes.