Ethereum: How to generate keypair completely offline?
Generating a Complete Offline Keypair on Ethereum: A Step-by-Step Guide
In recent years, concerns about data security and online anonymity have led to an increased interest in offline cryptography. One such approach is generating a complete offline keypair using dice, calculators, paper, and pen. This article will delve into the procedure and formulas used to create an offline Ethereum keypair.
What is an Offline Keypair?
An offline keypair consists of two private keys: one for public use (or signing) and another for secure storage (or private use). In this context, generating a complete offline keypair means creating both the public and private keys that can be used without needing to transmit them online.
Offline Ethereum Keypair Generation
To generate an offline Ethereum keypair using dice, calculators, paper, and pen, follow these steps:
Step 1: Choose a Seed Phrase or Masterseed
A seed phrase is a sequence of words that contain private keys for your Ethereum wallet. To create an offline keypair, you’ll need to generate a masterseed (or masterphrase) from this seed phrase.
You can use any method to derive the seed phrase from another private key, such as:
- Using a paper and pen-based approach
- Using a random number generator (RNG)
- Using a cryptographically secure pseudorandom number generator (CSPRNG)
For this example, we’ll assume you have a pre-generated masterseed.
Step 2: Create an Offline Ethereum Address
To create an offline Ethereum address, you can use the following formula:
offlineAddress = "0x" + masterseed.slice(0, 4) + "..."
Replace ... with the actual seed phrase in base64-encoded format (e.g., "aV1c2Vy").
For example:
offlineAddress = "0x9e6bf3b7..."
Step 3: Derive the Private Key from the Offline Address
To derive the private key, use a cryptographic hash function such as SHA-256 or BLAKE2. Here’s an example using SHA-256:
privateKey = offlineAddress.split("0x")[1].replace("+", "")
Step 4: Derive the Private Key from the Offline Address and Seed Phrase
To derive the private key from the offline address, seed phrase, and a public key (not shown here), you can use a cryptographic hash function like SHA-256 or BLAKE2.
privateKey = offlineAddress.split("0x")[1].replace("+", "")
Step 5: Derive the Private Key from the Offline Address and Seed Phrase (continued)
To derive the private key from the offline address, seed phrase, a public key, and another hash function like SHA-256 or BLAKE2, use the following formula:
privateKey = offlineAddress.split("0x")[1].replace("+", "")
python
def derive_private_key(offline_address, seed_phrase):
masterseed = seed_phrase.replace(” “, “”)
private_key_derived_from_masterseed = offline_address[:4] + masterseed[:5]
private_key_derived_from_seedphrase = offline_address[6:]
Remove “0x” prefix
return derive_private_key_from_hash(private_key_derived_from_masterseed, private_key_derived_from_seedphrase)
def derive_private_key_from_hash(hash_value, seed_phrase):
hash_value_base64 = base64.b64encode(hash_value).decode(‘utf-8’)
masterseed = hash_value_base64[:4]
return offline_address[:4] + masterseed[:5]
offline_address = “0x9e6bf3b7…”
private_key = derive_private_key(offline_address, offline_address)
print(private_key)
Output: your private key in hexadecimal format
“`
Conclusion
Generating an offline Ethereum keypair using dice, calculators, paper, and pen is a feasible approach for achieving complete offline anonymity. By following the steps outlined above, you can create a secure offline Ethereum wallet that can be used without transmitting sensitive information online.