When you use the sui keytool generate command, the output is indeed in a Base64 format. The .key file generated contains Base64 encoded information, including the keypair. You typically don't need to extract Base64 from it separately unless you have specific needs for the Base64 string itself.

A .key file usually stores your private key in raw bytes or hex format, not Base64. To convert it to Base64 (or extract Base64 if already encoded), you first need to inspect its format: • If it’s hex‑encoded (common for Sui keys): Convert hex → raw bytes → Base64. • If it’s already Base64 (starts with MIIB… or has = padding): You can use it directly without conversion. • If it’s raw binary: Encode the bytes directly to Base64.

Example using Node.js:

const fs = require('fs');

// Read .key file const keyData = fs.readFileSync('mykey.key', 'utf8').trim();

// If hex → convert to Base64 const base64Key = Buffer.from(keyData, 'hex').toString('base64'); console.log(base64Key);

Example using Python:

import base64

with open('mykey.key', 'r') as f: hex_data = f.read().strip()

base64_key = base64.b64encode(bytes.fromhex(hex_data)).decode() print(base64_key)

Once you have the Base64 string, you can import it into tools or SDKs that require Base64 keys (e.g., for Sui wallet operations).

If your key file was created using a tool like sui keytool, the entire content should be Base64 encoded. However, if you want to confirm or use it as a Base64 string elsewhere, you can read the file content as you would any text file, as it's already in a Base64 formatted string.

When you use the sui keytool generate command, the output is indeed in a Base64 format. The .key file generated contains Base64 encoded information, including the keypair. You typically don't need to extract Base64 from it separately unless you have specific needs for the Base64 string itself.