/**
 * file: karbytes_10_october_2024.txt
 * type: plain-text
 * date: 05_OCTOBER_2024
 * author: karbytes
 * license: PUBLIC_DOMAIN
 */

The following conversation transcript was slightly modified for stylistic purposes and taken from a conversation had between karbytes and ChatGPT-4o at approximately 1:30PM Pacific Standard Time on 05_OCTOBER_2024. The conversation pertains to karbytes’ hosting its own .onion web page on a local (Linux) machine and how to keep the address of that .onion web page unchanged when moving that web page to a new server machine (in order to keep that .onion web page relatively easy to locate on the dark web (which is accessible via The Onion Router (Tor) web browser) instead of changing that .onion web page’s address).

* * *

karbytes:

How are .onion web page addresses generated (and are they unique global addresses)?

ChatGPT:

.onion web page addresses are generated through a process that involves creating a unique cryptographic key pair, specifically for use within the Tor network. Here’s an overview of how it works:

1. Key Pair Generation:

– When a Tor service (such as a website or server) is set up, the Tor software generates a public-private key pair using elliptic curve cryptography (earlier versions used RSA keys).

– The private key is kept secret and is used to sign data, while the public key is used to derive the .onion address.

2. Address Derivation:

– The .onion address is derived from the hash of the public key. Specifically, a portion of the public key is hashed, and the first 16 or 56 characters of the base32-encoded hash form the .onion address.

– V2 addresses (which are deprecated) use 16 characters derived from an RSA public key.

– V3 addresses (the current standard) are 56 characters long and based on an elliptic curve public key.
This process ensures that each .onion address corresponds uniquely to its cryptographic key pair.

3. Global Uniqueness:

– Yes, .onion addresses are globally unique. Since the address is based on a cryptographic hash of the public key, no two addresses can be the same unless they are generated from the same key pair. This ensures that when you visit a particular .onion address, you’re accessing the correct hidden service tied to that key pair.

4. Vanity Addresses:

– Some people generate .onion addresses with custom prefixes (called “vanity addresses”) using brute force techniques to find a public key that produces a hash with the desired starting characters. This is computationally expensive but possible for short prefixes.

In summary, .onion addresses are generated using cryptographic keys and are unique globally due to the nature of the hash function applied to those keys.

karbytes:

Is it possible to preserve the address of a particular .onion web page I currently have hosted on a local server I own if I get a new computer to serve that web page?

ChatGPT:

Yes, it is possible to preserve the .onion address of a Tor hidden service when moving to a new computer. The .onion address is tied to the private key that was generated when you initially set up the hidden service. If you transfer that key to the new server, you can maintain the same .onion address. Here’s how you can do it:

Steps to Preserve the .onion Address:

1. Locate the Hidden Service Directory:

On the computer where you are currently hosting the Tor hidden service, find the directory where the Tor service stores the private key and hostname for the .onion address. By default, this is often located in:

– Linux/Unix: /var/lib/tor/hidden_service/

– Windows: Depends on where Tor is installed, but it should have a similar directory structure.

Inside this folder, you’ll find two important files:

– private_key: This file contains the cryptographic private key that is used to generate the .onion address.

– hostname: This file contains the actual .onion address for your hidden service.

2. Backup the Private Key:

– Copy the entire hidden service directory, or at least the private_key file. This is the crucial file that determines your .onion address. Without this key, you cannot preserve the original address.

3. Move to the New Server:

– Set up Tor on your new computer.

– Before starting the hidden service on the new machine, copy the private_key file (and optionally the hostname file) from your backup into the new hidden service directory on the new server (usually something like /var/lib/tor/hidden_service/).

4. Start the Hidden Service on the New Server:

– Once the private_key is in place, start or restart the Tor service on the new server. Tor will use the copied private key to ensure the same .onion address is served from the new machine.

Important Notes:

– Private Key Security: The private key must be kept secure. Anyone with access to this key can potentially host a service using your .onion address.

– Same Address, New Content: You can serve new content (or the same content) on the new server, but as long as you use the same private key, the .onion address will remain the same.

– Permissions: Ensure that the permissions on the hidden service directory and the private_key file are correct after moving them to the new server. Tor usually requires strict permissions to ensure the files aren’t accessible by unauthorized users.

By following these steps, you can effectively preserve your .onion address when moving the service to a new computer.

karbytes:

I found the files on my local (Linux) machine which contain that private key (hs_ed25519_secret_key) and that public key (hs_ed25519_public_key) in the file directory you specified alongside another file (hostname) containing the web address of my .onion web page. Although I was able to open and view the contents of hostname, I apparently need special software to open the other two files. How do I go about doing that?

ChatGPT:

The hs_ed25519_secret_key and hs_ed25519_public_key files that you found are in binary format, as they contain cryptographic keys. They aren’t meant to be directly human-readable, but they can be opened or converted into a more readable form using specific tools.

Tools for Opening and Viewing Ed25519 Keys

1. Using openssl: openssl is a widely available tool for working with cryptographic keys, though its support for Ed25519 keys is somewhat limited. It might not directly support viewing Ed25519 keys in the simplest format but can be useful for converting between key formats if needed.

2. Using Python with Cryptography Libraries: You can use Python with libraries like cryptography or PyNaCl to read and manipulate Ed25519 keys. This method requires a bit of coding but will allow you to extract and view the public and private keys in a human-readable format.

Here’s an example Python script using the cryptography library to read an Ed25519 private key:

Installation:

First, install the cryptography library if you don’t already have it:

[bash]

pip install cryptography

Code to Read the Secret Key:

[python]

from cryptography.hazmat.primitives.asymmetric import ed25519
from cryptography.hazmat.backends import default_backend

# Read the binary file containing the private key
with open('hs_ed25519_secret_key', 'rb') as key_file:
    private_key_data = key_file.read()

# Load the private key (this skips the first byte, which is a format identifier)
private_key = ed25519.Ed25519PrivateKey.from_private_bytes(private_key_data[1:])

# Get the raw private and public bytes
raw_private_bytes = private_key.private_bytes(
    encoding=cryptography.hazmat.primitives.serialization.Encoding.Raw,
    format=cryptography.hazmat.primitives.serialization.PrivateFormat.Raw,
    encryption_algorithm=cryptography.hazmat.primitives.serialization.NoEncryption()
)

# Print the raw private key
print(f"Private key (hex): {raw_private_bytes.hex()}")
Code to Read the Public Key:
Similarly, you can read the public key using this:

python
Copy code
with open('hs_ed25519_public_key', 'rb') as key_file:
    public_key_data = key_file.read()

# The public key is stored directly in the file, so no need to skip the first byte
public_key = ed25519.Ed25519PublicKey.from_public_bytes(public_key_data)

# Print the public key in hexadecimal
print(f"Public key (hex): {public_key.public_bytes().hex()}")
Using nacl (PyNaCl): PyNaCl is another Python library that supports Ed25519 keys. If you prefer PyNaCl, you can follow a similar approach to reading and displaying the keys.

Installation:

[bash]

pip install pynacl

Code to Read the Keys:

[python]

import nacl.signing

# Reading the private key
with open('hs_ed25519_secret_key', 'rb') as f:
    private_key_data = f.read()[1:]  # Skip the first byte, which is a format indicator

private_key = nacl.signing.SigningKey(private_key_data)
print(f"Private key (hex): {private_key.encode().hex()}")

# Reading the public key
with open('hs_ed25519_public_key', 'rb') as f:
    public_key_data = f.read()

public_key = nacl.signing.VerifyKey(public_key_data)
print(f"Public key (hex): {public_key.encode().hex()}")

Summary:

– hostname is human-readable and contains the .onion address.

– hs_ed25519_secret_key contains your private key in a binary format.

– hs_ed25519_public_key contains the corresponding public key in binary format.

If you only need to back up the keys or transfer them to another machine, you don’t need to open them; just copy the binary files. But if you want to inspect the keys, using a Python script with cryptography or PyNaCl is a good option.

* * *

Viewing the Ed25519 private and public keys

* * *

karbytes used the following command line command to install the cryptography package (on a Ubuntu/Debian-based system):

sudo apt install python3-cryptography

Then karbytes worked with ChatGPT-4o to modify the Python code (which was generated during the conversation whose transcript is displayed in the section above this section of this web page) such that it karbytes was able to successfully run both of those Python programs to decrypt the Ed25519 binary files in order to view the private and public keys as alphanumeric sequences.

(For security reasons, karbytes did not upload the output plain-text files named tor_private_key_file_reader_OUTPUT.txt and tor_public_key_file_reader_OUTPUT.txt to the public karbytes-owned GitHub repository named KARLINA_OBJECT_extension_pack_22 nor to any other private or public GitHub repository. karbytes did, however, upload those output files’ respective Ed25519 binary files named hs_ed25519_secret_key and hs_ed25519_public_key and, also, the human-readable file named hostname to a private GitHub repository which karbytes owns named karbytes_basement_n).

* * *

python_source_file_0: https://raw.githubusercontent.com/karlinarayberinger/KARLINA_OBJECT_extension_pack_22/main/tor_private_key_file_reader.py

#########################################################################################
# file: tor_private_key_file_reader.py
# type: Python
# date: 05_OCTOBER_2024
# author: karbytes
# license: PUBLIC_DOMAIN 
#########################################################################################

import sys  # for printing to (and possibly generating) the output file
from cryptography.hazmat.primitives.asymmetric import ed25519
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import serialization  # Import missing module

# Read the binary file containing the private key
key_file_path = 'hs_ed25519_secret_key'  # Ensure the correct path is used

try:
    with open(key_file_path, 'rb') as key_file:
        private_key_data = key_file.read()

    # Open the file for writing (and generate that file if it does not exist)
    with open("tor_private_key_file_reader_OUTPUT.txt", "w") as output_file:
        
        # Print the entire file in hex format to inspect its structure
        print(f"Private key file content (hex): {private_key_data.hex()}")
        print(f"Private key file length: {len(private_key_data)} bytes")

        # Write to the output file
        output_file.write(f"Private key file content (hex): {private_key_data.hex()}\n")
        output_file.write(f"Private key file length: {len(private_key_data)} bytes\n")

        # Assuming the first 32 bytes contain the actual private key
        if len(private_key_data) >= 32:
            actual_private_key = private_key_data[:32]  # Extract the first 32 bytes
            
            # Load the private key
            private_key = ed25519.Ed25519PrivateKey.from_private_bytes(actual_private_key)
            
            # Get the raw private bytes
            raw_private_bytes = private_key.private_bytes(
                encoding=serialization.Encoding.Raw,
                format=serialization.PrivateFormat.Raw,
                encryption_algorithm=serialization.NoEncryption()
            )
            
            # Print the raw private key in hexadecimal format
            print(f"Extracted Private key (hex): {raw_private_bytes.hex()}")
            output_file.write(f"Extracted Private key (hex): {raw_private_bytes.hex()}\n")
        else:
            print("Error: The file does not contain enough data for a 32-byte Ed25519 private key.")
            output_file.write("Error: The file does not contain enough data for a 32-byte Ed25519 private key.\n")

except FileNotFoundError:
    print(f"Error: The file {key_file_path} was not found.")
except Exception as e:
    print(f"An error occurred: {e}")

* * *

python_source_file_1: https://raw.githubusercontent.com/karlinarayberinger/KARLINA_OBJECT_extension_pack_22/main/tor_public_key_file_reader.py

#########################################################################################
# file: tor_public_key_file_reader.py
# type: Python
# date: 05_OCTOBER_2024
# author: karbytes
# license: PUBLIC_DOMAIN 
#########################################################################################

# import for serialization
from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives.asymmetric import ed25519

# Read the binary file containing the public key
key_file_path = 'hs_ed25519_public_key'  # Ensure the correct path is used
output_file_path_public = 'tor_public_key_file_reader_OUTPUT.txt'  # Output file path

try:
    with open(key_file_path, 'rb') as key_file:
        public_key_data = key_file.read()

    # Open the file for writing (and generate that file if it does not exist)
    with open(output_file_path_public, "w") as output_file:
        
        # Print the entire file in hex format to inspect its structure
        print(f"Public key file content (hex): {public_key_data.hex()}")
        print(f"Public key file length: {len(public_key_data)} bytes")

        # Write to the output file
        output_file.write(f"Public key file content (hex): {public_key_data.hex()}\n")
        output_file.write(f"Public key file length: {len(public_key_data)} bytes\n")

        # Since the file length is 64 bytes, let's assume the second half contains the 32-byte public key
        if len(public_key_data) == 64:
            actual_public_key = public_key_data[32:]  # Extract the last 32 bytes
            
            # Load the public key
            public_key = ed25519.Ed25519PublicKey.from_public_bytes(actual_public_key)
            
            # Get the raw public bytes (this step is technically redundant since we already have the public key data)
            raw_public_bytes = public_key.public_bytes(
                encoding=serialization.Encoding.Raw,
                format=serialization.PublicFormat.Raw
            )
            
            # Print the raw public key in hexadecimal format
            print(f"Extracted Public key (hex): {raw_public_bytes.hex()}")
            output_file.write(f"Extracted Public key (hex): {raw_public_bytes.hex()}\n")
        else:
            print("Error: The file does not contain a valid 32-byte Ed25519 public key.")
            output_file.write("Error: The file does not contain a valid 32-byte Ed25519 public key.\n")

except FileNotFoundError:
    print(f"Error: The file {key_file_path} was not found.")
except Exception as e:
    print(f"An error occurred: {e}")

# Return the output file path
output_file_path_public