Generating Personalized Bitcoin Addresses and Altcoins

The Problem with Random Bitcoin Addresses

For those who have used Bitcoin, you might have noticed that Bitcoin addresses can be quite unwieldy – they’re difficult to remember and aesthetically unpleasing. A typical Bitcoin address looks like this:

1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa

While secure, such addresses present several challenges:

• Memorability: Impossible to remember for humans
• Verification: Easy to make copy-paste errors when sending funds
• Branding: Businesses cannot incorporate their brand into addresses
• Trust: Recipients cannot easily verify address authenticity

This article introduces vanity address generation – a method to create personalized Bitcoin addresses with custom prefixes like 1Love..., 1Bitcoin..., or 1YourName....

Understanding Bitcoin Address Generation

If you’re unfamiliar with how Bitcoin addresses are generated, here’s the technical sequence:

Standard Address Generation Process

graph TD
    A[Generate Random<br/>256-bit Private Key] -->|ECDSA secp256k1| B[Calculate Public Key<br/>PubKey = PrivKey × G]
    B -->|SHA-256| C[Hash Public Key<br/>256-bit output]
    C -->|RIPEMD-160| D[Public Key Hash<br/>20 bytes]
    D -->|Add Version Byte 0x00| E[Versioned Hash<br/>21 bytes]
    E -->|Double SHA-256<br/>Take first 4 bytes| F[Add Checksum<br/>25 bytes total]
    F -->|Base58 Encode| G[Bitcoin Address<br/>1A1zP1eP5Q...]

    style A fill:#4CAF50
    style B fill:#2196F3
    style C fill:#FF9800
    style D fill:#FF9800
    style E fill:#9C27B0
    style F fill:#00BCD4
    style G fill:#4CAF50

Address Generation Steps:

1. Generate Random Number: Create a 256-bit random private key
2. Elliptic Curve Cryptography: Calculate public key using secp256k1 curve: Public Key = Private Key × G (where G is the generator point)
3. Hash Functions:
   • Apply SHA-256 to public key
   • Apply RIPEMD-160 to SHA-256 result
4. Add Version Byte: Prefix with 0x00 for mainnet
5. Checksum: Calculate double SHA-256 of versioned hash, append first 4 bytes
6. Base58 Encoding: Encode the result into human-readable format (26-35 characters starting with ‘1’)

Critical Property: A randomly generated private key corresponds to one unique address, which cannot be reverse-engineered. Given an address, it’s computationally infeasible to derive the private key (this is the foundation of Bitcoin’s security).

Vanity Address Generation with Vanitygen

To create special addresses, you can use the open-source tool vanitygen¹. This powerful software uses brute-force searching to find private keys that produce addresses with your desired prefix.

How Vanitygen Works

Vanitygen employs a simple but computationally intensive algorithm:

1. Generate Random Private Key: Create a random 256-bit number
2. Derive Address: Perform the full address generation sequence
3. Pattern Matching: Check if the resulting address starts with your desired prefix
4. Repeat: If no match, generate another random key and repeat

This is essentially a trial-and-error search through the vast space of possible private keys (2²⁵⁶ possibilities) until finding one that produces your desired address prefix.

Difficulty and Computation Time

The difficulty of generating a vanity address grows exponentially with each additional character:²

Note: Base58 alphabet excludes confusing characters (0, O, I, l), so there are 58 possible characters per position.

Example: Generating an address starting with “1Bitcoin” (7 characters after ‘1’) could take approximately 2-3 weeks using a high-end GPU or several years on CPU.

CPU vs GPU Performance

Vanitygen supports both CPU and GPU acceleration:

CPU Mode:

• Speed: ~100,000 - 500,000 keys/second (modern CPU)
• Pros: Available on any computer, no special setup
• Cons: 100-1000x slower than GPU

GPU Mode (using OpenCL/CUDA):

• Speed: ~50-200 million keys/second (high-end GPU)
• Pros: Massively parallel computation, 100-1000x faster
• Cons: Requires compatible GPU, higher power consumption

Performance Benchmark (approximate):

• Intel i7 CPU: ~400,000 keys/sec
• NVIDIA RTX 3080: ~150 million keys/sec
• AMD RX 6800: ~120 million keys/sec

Multi-Currency Support

Additionally, there was previously an advanced version called vanitygen-plus (formerly at exploitagency/vanitygen-plus, now archived), which was based on samr7/vanitygen and supported a wide range of cryptocurrencies:

• Bitcoin Family: Bitcoin, Bitcoin Testnet, Bitcoin Cash
• Altcoins: Litecoin, Dogecoin, Dash, Monacoin, Namecoin, Peercoin
• Privacy Coins: DeepOnion, Blackcoin
• Others: Many additional cryptocurrencies with similar address formats

For multi-currency support, users may find active forks by searching GitHub for “vanitygen” alternatives or exploring newer tools that support modern address formats (Bech32, SegWit).

Practical Usage Guide

Basic Usage Examples

Generate address starting with “1Love”:

./vanitygen 1Love

Case-insensitive search (finds 1love, 1Love, 1LOVE, etc.):

./vanitygen -i 1love

Regular expression pattern (addresses ending with “xyz”):

./vanitygen 1.*xyz

GPU acceleration:

./oclvanitygen -D 0:0 1Love
# -D 0:0 specifies platform:device

Multiple patterns simultaneously:

./vanitygen 1Love 1Bitcoin 1Satoshi

Real-World Use Cases

1. Business Branding

• Exchanges: 1Binance..., 1Coinbase...
• Merchants: 1Shop..., 1Store...
• Services: 1Donate..., 1Tips...

2. Personal Identification

• Names: 1Alice..., 1Bob...
• Dates: 1Jan2024...
• Memorable words: 1Lucky..., 1Happy...

3. Enhanced Verification

• Donation addresses easily recognizable
• Reduces risk of address substitution attacks
• Visual confirmation for regular recipients

Critical Security Considerations

1. Randomness is Paramount

A crucial aspect to note is that the security of these generated addresses heavily relies on the randomness of the number generator used. It’s essential to verify the reliability of the random number generator in these tools:

Good Practices:

• Use reputable, open-source tools with audited code
• Ensure your system’s entropy pool is sufficient (/dev/random on Linux)
• Avoid online vanity address generators (they could steal private keys)

Bad Practices:

• ❌ Never use online “vanity address services” that generate keys for you
• ❌ Don’t trust closed-source tools
• ❌ Avoid tools with suspicious or unaudited random number generation

2. The 2013 Android Wallet Vulnerability Lesson

History provides a cautionary tale: In 2013, Android Bitcoin wallets suffered from weak random number generation, leading to duplicate private keys and theft of 55.82 BTC. This demonstrates that poor randomness = compromised security, regardless of cryptographic strength.

3. Split-Key Vanity Generation

For maximum security, consider split-key vanity generation:

1. Third-Party Generates Partial Key: An untrusted party searches for the vanity prefix
2. You Add Your Random Key: Combine their partial key with your own random private key
3. Result: Address with desired prefix, but the third party never had the full private key

This allows using faster third-party services without trusting them with fund access.

4. Verify Your Tools

Before using any vanity address generator:

• Check GitHub stars/forks (samr7/vanitygen has 2,000+ stars)
• Read source code or get security audit results
• Compile from source rather than downloading pre-built binaries
• Test with small amounts before using for significant funds

Advanced Tips and Tricks

Case Sensitivity Matters

Bitcoin addresses are case-sensitive. The difficulty difference is substantial:

• 1Love (specific case): Moderate difficulty
• -i 1love (any case): 58x easier due to case-insensitive matching

Regex Patterns for Creative Addresses

# Address ending with "end"
./vanitygen 1.*end$

# Address containing "love" anywhere
./vanitygen 1.*love

# Multiple words
./vanitygen "1.*(love|moon|star)"

Monitoring Generation Progress

Vanitygen displays real-time statistics:

Difficulty: 264104224
Pattern: 1Bitcoin
Address: 1BitcoinA8kS9fj3K2mP5zE6nQ7xR4yW
Pubkey: 04a1b2c3d4...
Privkey: 5Kb8kLf9zgWQnogidDA76MzPL6TsZZY36hWXMssSzNydYXYB9KF
[Current speed: 154.23 Mkey/s]

This helps estimate remaining time based on current hash rate.

Alternatives and Modern Developments

SegWit and Bech32 Addresses

Modern Bitcoin uses SegWit addresses (starting with “bc1”) which offer:

• Lower transaction fees
• Better error detection
• Native SegWit format

Generating vanity Bech32 addresses requires updated tools supporting the new format.

Risks of Vanity Addresses

While convenient, vanity addresses have trade-offs:

Pros:

• ✅ Memorable and brandable
• ✅ Easy verification for regular users
• ✅ Professional appearance for businesses

Cons:

• ❌ Reveals you spent computational resources (potential wealth signal)
• ❌ Longer prefixes are expensive to generate
• ❌ Increases attack surface if using untrusted generators

Conclusion: Balance Convenience with Security

Vanity Bitcoin addresses offer a practical way to make cryptocurrency more user-friendly while maintaining security—provided you follow best practices. The key takeaways:

1. Only use trusted, open-source tools like samr7/vanitygen
2. Never trust online generators with your private keys
3. Verify randomness of the generator
4. Start small with 4-5 character prefixes (reasonable generation time)
5. Use GPU acceleration for faster results on longer prefixes

For the technically inclined, vanity address generation demonstrates the elegant mathematics underlying Bitcoin’s cryptographic security while providing a tangible benefit: addresses that are easier to recognize, remember, and verify.

Whether you’re a business seeking brand recognition or an individual wanting a personalized touch to your Bitcoin address, vanitygen makes it possible—just remember that security comes first, and convenience second.

References