Blake2b-512 Security-Focused API Documentation
Version: 1.0
Last Updated: 2025-07-05
**Security Classification: PUBLIC
Author: Phantom (phantom@metamui.id)
Overview
BLAKE2b-512 is a cryptographic hash function that produces 512-bit (64-byte) hash values. It’s the full-output variant of BLAKE2b, offering maximum security with performance exceeding MD5, SHA-1, SHA-2, and SHA-3. BLAKE2b supports keyed hashing (MAC), salting, and personalization, making it versatile for various cryptographic applications.
Security Level: 256-bit collision resistance, 512-bit preimage resistance
Output Size: 64 bytes (512 bits)
Block Size: 128 bytes
Key Size: 0-64 bytes (optional)
Salt/Personalization: 16 bytes each (optional)
Security Warnings ⚠️
- Maximum Security: Provides highest security level of BLAKE2b family
- No Length Extension: Immune to length extension attacks
- Side-Channel Resistant: Designed for constant-time implementation
- Key Size Limit: Keys > 64 bytes are hashed first
- Quantum Resistance: ~256-bit security against Grover’s algorithm
API Functions
blake2b512(message: bytes, key: bytes = b"", salt: bytes = b"", person: bytes = b"") -> bytes[64]
Security Contract:
- Preconditions:
messagecan be any length (0 to 2^128 bytes)keymust be 0-64 bytes (optional for MAC mode)saltmust be exactly 16 bytes if providedpersonmust be exactly 16 bytes if provided
- Postconditions:
- Returns exactly 64 bytes of hash output
- Same inputs always produce same output
- Keyed mode provides MAC functionality
Attack Resistance: | Attack Type | Protected | Notes | |————-|———–|——-| | Collision | ✅ | 2^256 expected attempts | | Preimage | ✅ | 2^512 expected attempts | | Second Preimage | ✅ | 2^512 expected attempts | | Length Extension | ✅ | HAIFA construction prevents | | Side-Channel | ✅ | Constant-time design | | Quantum (Grover’s) | ✅ | ~256-bit effective security |
Security Requirements:
- Use random salt for each application domain
- Personalization provides domain separation
- Keys should be high entropy for MAC usage
- Consider tree mode for large data
Secure Usage Example:
import hashlib
import secrets
import time
import struct
from typing import Dict, Optional, List, Union, Tuple
from dataclasses import dataclass
@dataclass
class Blake2b512Result:
hash_value: bytes
hex_digest: str
algorithm: str = "BLAKE2b-512"
computation_time: float = 0.0
class SecureBLAKE2b512:
"""Secure BLAKE2b-512 implementation with comprehensive features"""
def __init__(self, default_person: bytes = b""):
self.default_person = self._pad_personalization(default_person)
self.operation_count = 0
self.performance_metrics = {
'total_bytes': 0,
'total_time': 0.0
}
def hash_with_full_params(
self,
data: Union[bytes, str],
key: Optional[bytes] = None,
salt: Optional[bytes] = None,
person: Optional[bytes] = None,
context: Optional[str] = None
) -> Dict:
"""Hash with all BLAKE2b parameters"""
# Convert string to bytes if needed
if isinstance(data, str):
data = data.encode('utf-8')
# Validate and prepare parameters
if key and len(key) > 64:
raise ValueError("Key must be 0-64 bytes")
salt = self._pad_salt(salt) if salt else b'\x00' * 16
person = self._pad_personalization(person) if person else self.default_person
# Add context to personalization if provided
if context:
context_bytes = context.encode('utf-8')[:8]
person = self._merge_context(person, context_bytes)
start_time = time.perf_counter()
# Create BLAKE2b hasher
if key:
hasher = hashlib.blake2b(
data,
digest_size=64,
key=key,
salt=salt,
person=person
)
else:
hasher = hashlib.blake2b(
data,
digest_size=64,
salt=salt,
person=person
)
hash_value = hasher.digest()
end_time = time.perf_counter()
computation_time = end_time - start_time
self.operation_count += 1
self.performance_metrics['total_bytes'] += len(data)
self.performance_metrics['total_time'] += computation_time
return {
'hash': hash_value.hex(),
'algorithm': 'BLAKE2b-512',
'key_mode': bool(key),
'salt': salt.hex() if salt != b'\x00' * 16 else None,
'personalization': person.hex() if person != b'\x00' * 16 else None,
'context': context,
'input_size': len(data),
'computation_time': computation_time,
'operations_count': self.operation_count
}
def create_mac(
self,
key: bytes,
message: bytes,
domain: Optional[str] = None
) -> Dict:
"""Create BLAKE2b MAC with domain separation"""
if not key:
raise ValueError("Key required for MAC mode")
if len(key) < 16:
raise ValueError("Key should be at least 16 bytes for security")
# Use domain as personalization
person = f"MAC:{domain}".encode('utf-8')[:16] if domain else b"BLAKE2b-MAC-v1.0"
result = self.hash_with_full_params(
data=message,
key=key,
person=person,
context=f"MAC_{domain}" if domain else "MAC"
)
result['mac_domain'] = domain
return result
def verify_mac(
self,
key: bytes,
message: bytes,
expected_mac: Union[str, bytes],
domain: Optional[str] = None
) -> Tuple[bool, Dict]:
"""Verify BLAKE2b MAC with constant-time comparison"""
# Compute MAC
computed = self.create_mac(key, message, domain)
# Convert expected MAC to hex if needed
if isinstance(expected_mac, bytes):
expected_mac = expected_mac.hex()
# Constant-time comparison
import hmac
is_valid = hmac.compare_digest(
computed['hash'],
expected_mac.lower()
)
return is_valid, {
'valid': is_valid,
'computed_mac': computed['hash'],
'expected_mac': expected_mac,
'domain': domain,
'verified_at': time.time()
}
def hash_with_key_derivation(
self,
password: Union[str, bytes],
salt: Optional[bytes] = None,
iterations: int = 1000,
derived_key_length: int = 64
) -> Dict:
"""BLAKE2b-based key derivation (simple PBKDF2-like)"""
if isinstance(password, str):
password = password.encode('utf-8')
if salt is None:
salt = secrets.token_bytes(16)
else:
salt = self._pad_salt(salt)
# Initial hash with salt
current = self.hash_with_full_params(
data=password,
salt=salt,
person=b"BLAKE2b-KDF-v1.0"
)['hash']
current = bytes.fromhex(current)
# Iterate
for i in range(1, iterations):
current = hashlib.blake2b(
current + struct.pack('>I', i),
digest_size=64,
salt=salt,
person=b"BLAKE2b-KDF-v1.0"
).digest()
# Derive final key
if derived_key_length <= 64:
derived_key = current[:derived_key_length]
else:
# Need multiple blocks
derived_key = bytearray()
block_count = (derived_key_length + 63) // 64
for i in range(block_count):
block = hashlib.blake2b(
current + struct.pack('>I', i),
digest_size=64
).digest()
derived_key.extend(block)
derived_key = bytes(derived_key[:derived_key_length])
return {
'derived_key': derived_key.hex(),
'salt': salt.hex(),
'iterations': iterations,
'key_length': derived_key_length,
'algorithm': 'BLAKE2b-KDF',
'warning': 'Use Argon2 for password hashing in production'
}
def create_hash_tree(
self,
data_blocks: List[bytes],
fanout: int = 2,
max_depth: int = 255
) -> Dict:
"""Create BLAKE2b hash tree for parallel hashing"""
if not data_blocks:
raise ValueError("No data blocks provided")
# Hash leaf nodes
leaf_hashes = []
for i, block in enumerate(data_blocks):
leaf_hash = hashlib.blake2b(
block,
digest_size=64,
fanout=fanout,
depth=0,
leaf_size=len(block),
node_offset=i,
node_depth=0,
inner_size=64,
last_node=(i == len(data_blocks) - 1)
).digest()
leaf_hashes.append(leaf_hash)
# Build tree
tree_levels = [leaf_hashes]
current_level = leaf_hashes
depth = 1
while len(current_level) > 1 and depth < max_depth:
next_level = []
for i in range(0, len(current_level), fanout):
# Combine up to 'fanout' nodes
nodes_to_hash = current_level[i:i+fanout]
combined = b''.join(nodes_to_hash)
node_hash = hashlib.blake2b(
combined,
digest_size=64,
fanout=fanout,
depth=depth,
node_depth=depth,
inner_size=64,
last_node=(i + fanout >= len(current_level))
).digest()
next_level.append(node_hash)
tree_levels.append(next_level)
current_level = next_level
depth += 1
root_hash = current_level[0]
return {
'root_hash': root_hash.hex(),
'tree_depth': len(tree_levels),
'leaf_count': len(data_blocks),
'fanout': fanout,
'algorithm': 'BLAKE2b-Tree',
'total_nodes': sum(len(level) for level in tree_levels)
}
def _pad_salt(self, salt: Optional[bytes]) -> bytes:
"""Pad or truncate salt to 16 bytes"""
if not salt:
return b'\x00' * 16
if len(salt) < 16:
return salt + b'\x00' * (16 - len(salt))
elif len(salt) > 16:
return salt[:16]
return salt
def _pad_personalization(self, person: Optional[bytes]) -> bytes:
"""Pad or truncate personalization to 16 bytes"""
if not person:
return b'\x00' * 16
if len(person) < 16:
return person + b'\x00' * (16 - len(person))
elif len(person) > 16:
return person[:16]
return person
def _merge_context(self, person: bytes, context: bytes) -> bytes:
"""Merge context into personalization"""
# XOR context into last 8 bytes of personalization
result = bytearray(person)
context_len = min(len(context), 8)
for i in range(context_len):
result[8 + i] ^= context[i]
return bytes(result)
# SECURE: File integrity with BLAKE2b
class Blake2bFileIntegrity:
"""File integrity verification using BLAKE2b-512"""
def __init__(self, master_key: Optional[bytes] = None):
self.blake2b = SecureBLAKE2b512()
self.master_key = master_key
self.manifest_version = "1.0"
def hash_file_with_metadata(
self,
file_path: str,
include_metadata: bool = True,
chunk_size: int = 1024 * 1024 # 1MB chunks
) -> Dict:
"""Hash file with optional metadata"""
import os
if not os.path.exists(file_path):
raise FileNotFoundError(f"File not found: {file_path}")
# Get file metadata
stat_info = os.stat(file_path)
# Create file-specific salt from metadata
if include_metadata:
salt_data = f"{stat_info.st_size}:{int(stat_info.st_mtime)}".encode()
salt = hashlib.sha256(salt_data).digest()[:16]
else:
salt = None
# Hash file content
hasher = hashlib.blake2b(
digest_size=64,
key=self.master_key if self.master_key else b"",
salt=salt if salt else b"\x00" * 16,
person=b"FileIntegrity1.0"
)
bytes_processed = 0
start_time = time.time()
with open(file_path, 'rb') as f:
while True:
chunk = f.read(chunk_size)
if not chunk:
break
hasher.update(chunk)
bytes_processed += len(chunk)
file_hash = hasher.digest()
end_time = time.time()
result = {
'file_path': file_path,
'hash': file_hash.hex(),
'algorithm': 'BLAKE2b-512',
'file_size': stat_info.st_size,
'bytes_processed': bytes_processed,
'processing_time': end_time - start_time,
'throughput_mbps': (bytes_processed / (1024 * 1024)) / (end_time - start_time),
'keyed': bool(self.master_key)
}
if include_metadata:
result['metadata'] = {
'size': stat_info.st_size,
'mtime': stat_info.st_mtime,
'mode': stat_info.st_mode,
'salt': salt.hex()
}
return result
def create_manifest(
self,
directory_path: str,
output_path: str,
recursive: bool = True
) -> Dict:
"""Create integrity manifest for directory"""
import os
manifest = {
'version': self.manifest_version,
'algorithm': 'BLAKE2b-512',
'created_at': time.time(),
'directory': directory_path,
'files': {}
}
files_processed = 0
for root, dirs, files in os.walk(directory_path):
if not recursive:
dirs.clear() # Don't recurse
for filename in files:
file_path = os.path.join(root, filename)
relative_path = os.path.relpath(file_path, directory_path)
try:
file_result = self.hash_file_with_metadata(file_path)
manifest['files'][relative_path] = {
'hash': file_result['hash'],
'size': file_result['file_size'],
'metadata': file_result.get('metadata', {})
}
files_processed += 1
except Exception as e:
manifest['files'][relative_path] = {
'error': str(e)
}
# Save manifest
import json
with open(output_path, 'w') as f:
json.dump(manifest, f, indent=2)
return {
'manifest_path': output_path,
'files_processed': files_processed,
'manifest_size': os.path.getsize(output_path)
}
def verify_manifest(
self,
manifest_path: str,
directory_path: str
) -> Dict:
"""Verify files against manifest"""
import json
with open(manifest_path, 'r') as f:
manifest = json.load(f)
verification_results = {
'valid_files': 0,
'invalid_files': 0,
'missing_files': 0,
'new_files': 0,
'details': []
}
# Check each file in manifest
for relative_path, expected in manifest['files'].items():
file_path = os.path.join(directory_path, relative_path)
if 'error' in expected:
continue
if not os.path.exists(file_path):
verification_results['missing_files'] += 1
verification_results['details'].append({
'file': relative_path,
'status': 'missing'
})
continue
try:
current = self.hash_file_with_metadata(file_path)
if current['hash'] == expected['hash']:
verification_results['valid_files'] += 1
status = 'valid'
else:
verification_results['invalid_files'] += 1
status = 'modified'
verification_results['details'].append({
'file': relative_path,
'status': status,
'expected_hash': expected['hash'],
'current_hash': current['hash']
})
except Exception as e:
verification_results['invalid_files'] += 1
verification_results['details'].append({
'file': relative_path,
'status': 'error',
'error': str(e)
})
return verification_results
Common Mistakes:
# INSECURE: Using truncated output
hash_value = blake2b(data).digest()[:16] # Only 128 bits!
# INSECURE: Weak key for MAC
mac = blake2b(message, key=b"1234") # Key too short and weak!
# INSECURE: No domain separation
mac1 = blake2b(msg1, key=key)
mac2 = blake2b(msg2, key=key) # Same key, no personalization
# INSECURE: Reusing salt
FIXED_SALT = b"app_salt_123456" # Salt should be unique per use
# INSECURE: Not using tree mode for large data
# Processing gigabytes sequentially instead of parallel tree mode
blake2b512_init(key: bytes = b"", salt: bytes = b"", person: bytes = b"") -> Blake2b512Context
Security Contract:
- Preconditions:
keymust be 0-64 bytessaltmust be 16 bytes if providedpersonmust be 16 bytes if provided
- Postconditions:
- Returns initialized BLAKE2b context
- Ready for update() calls
- Parameters locked after initialization
Security Notes:
- Context maintains state securely
- Can process data incrementally
- Tree parameters set at initialization
Secure Usage Example:
use blake2::{Blake2b512, Blake2bMac, Digest};
use blake2::digest::{KeyInit, FixedOutput, Update, Mac};
use std::io::{Read, BufReader};
/// Secure BLAKE2b-512 wrapper with safety features
pub struct SecureBlake2b512 {
personalization: [u8; 16],
operation_count: u64,
}
impl SecureBlake2b512 {
pub fn new(domain: &str) -> Self {
let mut personalization = [0u8; 16];
let domain_bytes = domain.as_bytes();
let copy_len = std::cmp::min(domain_bytes.len(), 16);
personalization[..copy_len].copy_from_slice(&domain_bytes[..copy_len]);
Self {
personalization,
operation_count: 0,
}
}
pub fn hash_with_params(
&mut self,
data: &[u8],
salt: Option<[u8; 16]>,
) -> Blake2b512Result {
use blake2::digest::crypto_common::BlockSizeUser;
let salt = salt.unwrap_or([0u8; 16]);
// Create hasher with parameters
let mut params = blake2::Params::new();
params.hash_length(64);
params.personal(&self.personalization);
params.salt(&salt);
let mut hasher = params.to_state();
hasher.update(data);
let result = hasher.finalize();
self.operation_count += 1;
Blake2b512Result {
hash: result.into(),
personalization: self.personalization,
salt,
operation_count: self.operation_count,
}
}
pub fn create_mac(
&mut self,
key: &[u8],
message: &[u8],
) -> Result<Blake2bMacResult, CryptoError> {
if key.is_empty() || key.len() > 64 {
return Err(CryptoError::InvalidKeySize);
}
type Blake2b512Mac = blake2::Blake2bMac<U64>;
let mut mac = Blake2b512Mac::new_from_slice(key)
.map_err(|_| CryptoError::MacCreationFailed)?;
mac.update(message);
let result = mac.finalize();
self.operation_count += 1;
Ok(Blake2bMacResult {
mac: result.into_bytes().into(),
key_size: key.len(),
})
}
pub fn verify_mac(
&self,
key: &[u8],
message: &[u8],
expected_mac: &[u8; 64],
) -> Result<bool, CryptoError> {
type Blake2b512Mac = blake2::Blake2bMac<U64>;
let mut mac = Blake2b512Mac::new_from_slice(key)
.map_err(|_| CryptoError::MacCreationFailed)?;
mac.update(message);
// Constant-time verification
mac.verify_slice(expected_mac)
.map(|_| true)
.map_err(|_| CryptoError::MacVerificationFailed)
}
}
#[derive(Debug)]
pub struct Blake2b512Result {
pub hash: [u8; 64],
pub personalization: [u8; 16],
pub salt: [u8; 16],
pub operation_count: u64,
}
#[derive(Debug)]
pub struct Blake2bMacResult {
pub mac: [u8; 64],
pub key_size: usize,
}
/// Streaming BLAKE2b for large files
pub struct StreamingBlake2b512 {
hasher: Blake2b512,
bytes_processed: u64,
chunks_processed: u32,
}
impl StreamingBlake2b512 {
pub fn new() -> Self {
Self {
hasher: Blake2b512::new(),
bytes_processed: 0,
chunks_processed: 0,
}
}
pub fn new_keyed(key: &[u8]) -> Result<Self, CryptoError> {
if key.len() > 64 {
return Err(CryptoError::InvalidKeySize);
}
let mut params = blake2::Params::new();
params.hash_length(64);
params.key(key);
Ok(Self {
hasher: params.to_state(),
bytes_processed: 0,
chunks_processed: 0,
})
}
pub fn update(&mut self, data: &[u8]) {
self.hasher.update(data);
self.bytes_processed += data.len() as u64;
self.chunks_processed += 1;
}
pub fn finalize(self) -> StreamingResult {
let hash = self.hasher.finalize();
StreamingResult {
hash: hash.into(),
bytes_processed: self.bytes_processed,
chunks_processed: self.chunks_processed,
}
}
pub fn hash_file(file_path: &str) -> Result<StreamingResult, std::io::Error> {
let file = std::fs::File::open(file_path)?;
let mut reader = BufReader::new(file);
let mut hasher = Self::new();
let mut buffer = [0u8; 8192];
loop {
let bytes_read = reader.read(&mut buffer)?;
if bytes_read == 0 {
break;
}
hasher.update(&buffer[..bytes_read]);
}
Ok(hasher.finalize())
}
}
#[derive(Debug)]
pub struct StreamingResult {
pub hash: [u8; 64],
pub bytes_processed: u64,
pub chunks_processed: u32,
}
/// BLAKE2b tree mode for parallel hashing
pub struct Blake2bTree {
fanout: u8,
max_depth: u8,
leaf_size: u32,
inner_hash_size: u8,
}
impl Blake2bTree {
pub fn new(fanout: u8, max_depth: u8) -> Self {
Self {
fanout: fanout.max(2),
max_depth: max_depth.max(2),
leaf_size: 0, // 0 means default
inner_hash_size: 64,
}
}
pub fn hash_parallel<T: AsRef<[u8]>>(
&self,
blocks: &[T],
) -> Result<[u8; 64], CryptoError> {
if blocks.is_empty() {
return Err(CryptoError::EmptyInput);
}
// Hash leaf nodes
let mut leaf_hashes: Vec<[u8; 64]> = blocks
.iter()
.enumerate()
.map(|(i, block)| self.hash_leaf(block.as_ref(), i))
.collect();
// Build tree bottom-up
let mut depth = 1;
while leaf_hashes.len() > 1 && depth < self.max_depth {
let mut next_level = Vec::new();
for chunk in leaf_hashes.chunks(self.fanout as usize) {
let inner_hash = self.hash_inner(chunk, depth);
next_level.push(inner_hash);
}
leaf_hashes = next_level;
depth += 1;
}
Ok(leaf_hashes[0])
}
fn hash_leaf(&self, data: &[u8], index: usize) -> [u8; 64] {
let mut params = blake2::Params::new();
params.hash_length(64);
params.fanout(self.fanout);
params.max_depth(self.max_depth);
params.node_depth(0);
params.node_offset(index as u64);
params.inner_hash_length(self.inner_hash_size);
let mut hasher = params.to_state();
hasher.update(data);
hasher.finalize().into()
}
fn hash_inner(&self, nodes: &[[u8; 64]], depth: u8) -> [u8; 64] {
let mut params = blake2::Params::new();
params.hash_length(64);
params.fanout(self.fanout);
params.max_depth(self.max_depth);
params.node_depth(depth);
params.inner_hash_length(self.inner_hash_size);
let mut hasher = params.to_state();
for node in nodes {
hasher.update(node);
}
hasher.finalize().into()
}
}
/// Key derivation using BLAKE2b
pub struct Blake2bKDF {
master_key: [u8; 64],
domain: String,
}
impl Blake2bKDF {
pub fn new(master_key: [u8; 64], domain: &str) -> Self {
Self {
master_key,
domain: domain.to_string(),
}
}
pub fn derive_key(
&self,
info: &[u8],
output_len: usize,
) -> Result<Vec<u8>, CryptoError> {
if output_len == 0 || output_len > 65536 {
return Err(CryptoError::InvalidOutputLength);
}
let mut output = Vec::with_capacity(output_len);
let blocks_needed = (output_len + 63) / 64;
for i in 0..blocks_needed {
let mut params = blake2::Params::new();
params.hash_length(64);
params.key(&self.master_key);
params.personal(self.domain.as_bytes());
let mut hasher = params.to_state();
hasher.update(&(i as u32).to_be_bytes());
hasher.update(info);
let block = hasher.finalize();
output.extend_from_slice(&block);
}
output.truncate(output_len);
Ok(output)
}
pub fn derive_subkeys(
&self,
labels: &[&str],
key_size: usize,
) -> Result<Vec<Vec<u8>>, CryptoError> {
let mut subkeys = Vec::new();
for label in labels {
let info = format!("{}:{}", self.domain, label);
let subkey = self.derive_key(info.as_bytes(), key_size)?;
subkeys.push(subkey);
}
Ok(subkeys)
}
}
use generic_array::typenum::U64;
#[derive(Debug)]
pub enum CryptoError {
InvalidKeySize,
InvalidOutputLength,
MacCreationFailed,
MacVerificationFailed,
EmptyInput,
}
blake2b512_update(ctx: &mut Blake2b512Context, data: bytes)
Security Contract:
- Preconditions:
- Context must be initialized
- Can be called multiple times
- No size limit per update
- Postconditions:
- Internal state updated securely
- Order of updates affects final hash
blake2b512_final(ctx: Blake2b512Context) -> bytes[64]
Security Contract:
- Preconditions:
- Context must be initialized
- May have zero or more updates
- Postconditions:
- Returns 64-byte final hash
- Context is consumed
Security Best Practices
Secure Parameter Usage
class Blake2bSecurityPatterns:
"""Security patterns for BLAKE2b-512 usage"""
@staticmethod
def create_domain_separated_hasher(domain: str) -> 'DomainHasher':
"""Create hasher with strong domain separation"""
class DomainHasher:
def __init__(self, domain: str):
# Use domain as personalization
self.person = f"Domain:{domain}".encode('utf-8')[:16]
self.person = self.person.ljust(16, b'\x00')
def hash(self, data: bytes, context: Optional[str] = None) -> bytes:
# Add context-specific salt if provided
if context:
salt = hashlib.sha256(f"{domain}:{context}".encode()).digest()[:16]
else:
salt = b'\x00' * 16
return hashlib.blake2b(
data,
digest_size=64,
salt=salt,
person=self.person
).digest()
def create_mac(self, key: bytes, message: bytes) -> bytes:
"""Create domain-specific MAC"""
return hashlib.blake2b(
message,
digest_size=64,
key=key,
person=self.person
).digest()
return DomainHasher(domain)
@staticmethod
def secure_password_hash(
password: str,
salt: Optional[bytes] = None,
time_cost: int = 3,
memory_cost: int = 64
) -> Dict:
"""BLAKE2b-based password hashing (demonstration)"""
# Note: Use Argon2 for production password hashing
if salt is None:
salt = secrets.token_bytes(16)
# Simulate memory-hard function
memory_buffer = bytearray(memory_cost * 1024) # KB
# Initial hash
state = hashlib.blake2b(
password.encode('utf-8'),
digest_size=64,
salt=salt,
person=b"PasswordHash-v1"
).digest()
# Time-cost iterations
for t in range(time_cost):
# Fill memory buffer
for i in range(0, len(memory_buffer), 64):
block = hashlib.blake2b(
state + struct.pack('>II', t, i),
digest_size=64
).digest()
copy_len = min(64, len(memory_buffer) - i)
memory_buffer[i:i+copy_len] = block[:copy_len]
# Mix with memory buffer
state = hashlib.blake2b(
state + bytes(memory_buffer),
digest_size=64,
salt=salt
).digest()
return {
'hash': state.hex(),
'salt': salt.hex(),
'time_cost': time_cost,
'memory_cost': memory_cost,
'algorithm': 'BLAKE2b-PasswordHash',
'warning': 'Use Argon2 for production'
}
@staticmethod
def create_commitment_scheme() -> 'CommitmentScheme':
"""Cryptographic commitment using BLAKE2b"""
class CommitmentScheme:
def commit(self, value: bytes, randomness: Optional[bytes] = None) -> Tuple[bytes, bytes]:
"""Create commitment to value"""
if randomness is None:
randomness = secrets.token_bytes(32)
# Commitment = BLAKE2b(randomness || value)
commitment = hashlib.blake2b(
randomness + value,
digest_size=64,
person=b"Commitment-v1.0"
).digest()
return commitment, randomness
def verify(self, commitment: bytes, value: bytes, randomness: bytes) -> bool:
"""Verify commitment"""
expected = hashlib.blake2b(
randomness + value,
digest_size=64,
person=b"Commitment-v1.0"
).digest()
import hmac
return hmac.compare_digest(commitment, expected)
def create_vector_commitment(self, values: List[bytes]) -> Dict:
"""Commit to multiple values efficiently"""
# Build Merkle tree with BLAKE2b
tree = []
# Leaf commitments
leaves = []
for i, value in enumerate(values):
leaf = hashlib.blake2b(
struct.pack('>I', i) + value,
digest_size=64,
person=b"VectorCommit-v1"
).digest()
leaves.append(leaf)
tree.append(leaves)
# Build tree
current_level = leaves
while len(current_level) > 1:
next_level = []
for i in range(0, len(current_level), 2):
if i + 1 < len(current_level):
combined = current_level[i] + current_level[i+1]
else:
combined = current_level[i]
parent = hashlib.blake2b(
combined,
digest_size=64,
person=b"VectorCommit-v1"
).digest()
next_level.append(parent)
tree.append(next_level)
current_level = next_level
return {
'root': current_level[0].hex(),
'tree_height': len(tree),
'leaf_count': len(values)
}
return CommitmentScheme()
Integration with Cryptographic Protocols
def blake2b_protocol_integration():
"""BLAKE2b in cryptographic protocols"""
class ProtocolSuite:
def __init__(self, shared_secret: bytes):
self.shared_secret = shared_secret
def key_exchange_confirmation(
self,
my_public: bytes,
peer_public: bytes,
transcript: bytes
) -> bytes:
"""Confirm key exchange using BLAKE2b"""
# Key confirmation tag
confirmation = hashlib.blake2b(
my_public + peer_public + transcript,
digest_size=64,
key=self.shared_secret,
person=b"KeyConfirm-v1.0"
).digest()
return confirmation[:32] # Return 256 bits
def derive_session_keys(
self,
handshake_hash: bytes,
key_count: int = 4
) -> Dict[str, bytes]:
"""Derive multiple session keys"""
keys = {}
labels = ['client_write', 'server_write', 'client_mac', 'server_mac']
for i, label in enumerate(labels[:key_count]):
key = hashlib.blake2b(
handshake_hash + struct.pack('>I', i),
digest_size=64,
key=self.shared_secret,
salt=label.encode('utf-8')[:16].ljust(16, b'\x00'),
person=b"SessionKeys-v1.0"
).digest()
keys[label] = key[:32] # 256-bit keys
return keys
def create_transcript_hash(
self,
messages: List[bytes]
) -> bytes:
"""Hash protocol transcript"""
hasher = hashlib.blake2b(
digest_size=64,
person=b"Transcript-v1.0"
)
for i, message in enumerate(messages):
# Add message with length prefix
hasher.update(struct.pack('>I', len(message)))
hasher.update(message)
# Add sequence number
hasher.update(struct.pack('>I', i))
return hasher.digest()
Common Integration Patterns
Blockchain and Cryptocurrency
def blake2b_blockchain_integration():
"""BLAKE2b in blockchain applications"""
class BlockchainHasher:
def __init__(self, chain_id: str):
self.chain_id = chain_id
self.blake2b = SecureBLAKE2b512()
def hash_block(
self,
block_data: Dict,
previous_hash: bytes,
nonce: int
) -> Dict:
"""Hash block with BLAKE2b"""
# Serialize block data
block_bytes = json.dumps(block_data, sort_keys=True).encode()
# Create block hash
block_input = (
previous_hash +
struct.pack('>Q', nonce) +
block_bytes
)
block_hash = hashlib.blake2b(
block_input,
digest_size=64,
salt=self.chain_id.encode('utf-8')[:16].ljust(16, b'\x00'),
person=b"BlockHash-v1.0"
).digest()
return {
'block_hash': block_hash.hex(),
'previous_hash': previous_hash.hex(),
'nonce': nonce,
'data_size': len(block_bytes),
'algorithm': 'BLAKE2b-512'
}
def mine_block(
self,
block_data: Dict,
previous_hash: bytes,
difficulty: int
) -> Dict:
"""Mine block with proof-of-work"""
target = '0' * difficulty
nonce = 0
while True:
result = self.hash_block(block_data, previous_hash, nonce)
if result['block_hash'].startswith(target):
result['mining_attempts'] = nonce + 1
result['difficulty'] = difficulty
return result
nonce += 1
if nonce > 2**32:
raise ValueError("Mining failed - nonce space exhausted")
def create_merkle_root(self, transactions: List[Dict]) -> str:
"""Create Merkle root of transactions"""
if not transactions:
return '0' * 128
# Hash transactions
tx_hashes = []
for tx in transactions:
tx_bytes = json.dumps(tx, sort_keys=True).encode()
tx_hash = hashlib.blake2b(
tx_bytes,
digest_size=64,
person=b"Transaction-v1"
).digest()
tx_hashes.append(tx_hash)
# Build Merkle tree
while len(tx_hashes) > 1:
next_level = []
for i in range(0, len(tx_hashes), 2):
if i + 1 < len(tx_hashes):
combined = tx_hashes[i] + tx_hashes[i + 1]
else:
combined = tx_hashes[i] + tx_hashes[i]
parent = hashlib.blake2b(
combined,
digest_size=64,
person=b"MerkleNode-v1"
).digest()
next_level.append(parent)
tx_hashes = next_level
return tx_hashes[0].hex()
Digital Signatures Enhancement
def blake2b_signature_enhancement():
"""Enhance digital signatures with BLAKE2b"""
class EnhancedSigner:
def __init__(self, signing_key: bytes):
self.signing_key = signing_key
self.blake2b = SecureBLAKE2b512()
def create_deterministic_nonce(
self,
message: bytes,
counter: int = 0
) -> bytes:
"""Create deterministic nonce for signatures"""
# RFC 6979-like deterministic nonce
nonce_input = (
self.signing_key +
message +
struct.pack('>Q', counter)
)
nonce = hashlib.blake2b(
nonce_input,
digest_size=64,
person=b"SigNonce-v1.0"
).digest()
return nonce[:32] # Return 256 bits
def hash_message_for_signing(
self,
message: bytes,
context: str,
timestamp: Optional[int] = None
) -> bytes:
"""Hash message with context for signing"""
# Build signing input
if timestamp is None:
timestamp = int(time.time())
context_bytes = context.encode('utf-8')
# Create structured hash
hasher = hashlib.blake2b(
digest_size=64,
person=b"MessageSign-v1.0"
)
# Add components with length prefixes
hasher.update(struct.pack('>I', len(context_bytes)))
hasher.update(context_bytes)
hasher.update(struct.pack('>Q', timestamp))
hasher.update(struct.pack('>I', len(message)))
hasher.update(message)
return hasher.digest()
Performance Considerations
| Operation | Speed (MB/s) | Notes |
|---|---|---|
| BLAKE2b-512 Hash | 500-1000 | Single-threaded |
| BLAKE2b-512 MAC | 450-950 | With key |
| BLAKE2b Tree Mode | 2000-4000 | Parallel processing |
| vs SHA-512 | 3-5x faster | Similar security |
| vs SHA3-512 | 5-10x faster | Different design |
Optimization Strategies
- Use tree mode for large files (>10MB)
- Leverage SIMD instructions when available
- Process data in aligned chunks
- Use streaming API for memory efficiency
- Consider BLAKE2bp for parallel processing
Security Auditing
Implementation Checklist
- Using full 512-bit output for maximum security
- Keys are high entropy and appropriate length
- Salt/personalization used for domain separation
- Tree mode parameters chosen correctly
- Constant-time operations for MAC verification
- No truncation below security requirements
- Proper parameter padding/validation
Common Vulnerabilities
# AUDIT: Look for these patterns
# ❌ Truncated output
short_hash = blake2b(data).digest()[:8] # Only 64 bits!
# ❌ Weak or missing key
mac = blake2b(message, key=b"") # No key!
mac = blake2b(message, key=b"key") # Weak key!
# ❌ No domain separation
hash1 = blake2b(data1)
hash2 = blake2b(data2) # Could collide across domains
# ❌ Missing salt for similar inputs
for user in users:
password_hash = blake2b(user.password) # No salt!
# ❌ Improper tree mode usage
# Using sequential mode for multi-GB files
Comparison with Alternatives
BLAKE2b-512 vs Other Hash Functions
| Feature | BLAKE2b-512 | SHA-512 | SHA3-512 | BLAKE3 | |———|————-|———|———-|———| | Speed | Excellent | Good | Fair | Best | | Security | 256-bit collision | 256-bit collision | 256-bit collision | 128-bit collision | | Keyed Mode | Native | HMAC needed | Native | Native | | Parallelizable | Tree mode | No | No | Always | | Standardization | RFC 7693 | FIPS 180-4 | FIPS 202 | Not yet |
When to Use BLAKE2b-512
- Need maximum security with good performance
- Require built-in MAC functionality
- Want flexibility (salt, personalization, tree mode)
- Replacing SHA-512 in existing systems
- Need proven security (cryptanalysis since 2012)
Security Analysis
Threat Model: BLAKE2b Threat Model
The comprehensive threat analysis covers:
- Algorithm-specific attack vectors
- Implementation vulnerabilities
- Side-channel considerations
- Quantum resistance analysis (where applicable)
- Deployment recommendations
For complete security analysis and risk assessment, see the dedicated threat model documentation.
References
- RFC 7693 - The BLAKE2 Cryptographic Hash and MAC
- BLAKE2 Official Website
- BLAKE2: simpler, smaller, fast as MD5
Support
Security Issues: security@metamui.id
Documentation Updates: phantom@metamui.id
Vulnerability Disclosure: See SECURITY.md
Document Version: 1.0
Review Cycle: Quarterly
Next Review: 2025-04-05
Classification: PUBLIC