BLAKE2s HASH

32-bit Optimized High-Performance Hash Function

Security Level 128 bit
Standardization RFC 7693
Performance ⭐⭐⭐⭐⭐
Quantum Safe ⚠️ Partial

🎯 Overview

BLAKE2s is the 32-bit optimized variant of BLAKE2, specifically designed for embedded systems, mobile devices, and 32-bit platforms. It delivers exceptional performance while maintaining strong cryptographic security, making it ideal for resource-constrained environments.

✨ Key Features

📱

32-bit Optimized

Designed specifically for embedded systems and 32-bit platforms

🔧

Variable Output

Configurable digest size from 1 to 32 bytes

🔑

Built-in MAC Mode

Native keyed hashing with up to 32-byte keys

Small Footprint

Minimal RAM and code size requirements

🌐

Domain Separation

Salt and personalization for different contexts

🌳

Tree Hashing

Supports parallel and tree hashing modes

🎯 Common Use Cases

🔌 Embedded Systems

IoT devices, microcontrollers, and resource-constrained platforms

📱 Mobile Applications

Efficient hashing on mobile devices and ARM processors

⛏️ Proof of Work

Cryptocurrency mining optimized for GPU architectures

✅ Fast Checksums

Rapid integrity checking with compact digest sizes

🔑 Lightweight KDF

Key derivation for constrained devices and protocols

✍️ Embedded Signatures

Hash function for signature schemes in embedded systems

🔧 Algorithm Parameters

Output Size

Range: 1-32 bytes

Default: 32 bytes (256 bits)

Common: 16 bytes (128 bits)

Key Size (MAC Mode)

Range: 0-32 bytes

Recommended: 16+ bytes

Purpose: Message authentication

Salt

Size: 8 bytes

Default: All zeros

Use: Randomization and uniqueness

Personalization

Size: 8 bytes

Default: All zeros

Use: Domain separation

Tree Parameters

Fanout: 0-255 (default: 1)

Depth: 0-255 (default: 1)

Use: Parallel processing

Node Parameters

Offset: 0-2^48

Depth: 0-255

Use: Tree structure

🔒 Security Properties

💥

Collision Resistance

2^128 for 32-byte output, 2^64 for 16-byte output

🔍

Preimage Resistance

2^256 for 32-byte output, 2^128 for 16-byte output

🔐

Second Preimage

2^256 resistance for maximum security

🔑

Keyed Mode Security

2^128 security for MAC usage with proper keys

🎲

Indifferentiability

Proven indifferentiable from random oracle

🛡️

Length Extension

Immune to length extension attacks by design

  • Second Preimage Resistance: 2^256
  • Keyed Mode Security: 2^128 for MAC usage
  • Side-Channel Resistance: No data-dependent operations

Implementation

Python Example

from metamui_crypto import BLAKE2s
import os

# Basic hashing
blake2s = BLAKE2s()
hash_value = blake2s.hash(b"Hello, World!")
print(f"BLAKE2s hash: {hash_value.hex()}")

# Custom digest size
blake2s_128 = BLAKE2s(digest_size=16)  # 128-bit output
hash_128 = blake2s_128.hash(b"Hello, World!")
print(f"BLAKE2s-128: {hash_128.hex()}")

# Keyed hashing (MAC mode)
key = os.urandom(32)
blake2s_mac = BLAKE2s(key=key)
mac = blake2s_mac.hash(b"Authenticated message")
print(f"BLAKE2s MAC: {mac.hex()}")

# Incremental hashing
hasher = BLAKE2s()
hasher.update(b"Hello, ")
hasher.update(b"World!")
final_hash = hasher.finalize()

# Personalization for domain separation
blake2s_iot = BLAKE2s(personalization=b"IoTAuth1")
blake2s_mobile = BLAKE2s(personalization=b"MobileAp")

# Salt for randomization
salt = os.urandom(8)
blake2s_salted = BLAKE2s(salt=salt)
salted_hash = blake2s_salted.hash(b"Data to hash")

Advanced Usage

# Embedded system authentication
class EmbeddedAuth:
    def __init__(self, device_key: bytes):
        self.device_key = device_key
        self.hasher = BLAKE2s(key=device_key, digest_size=16)
    
    def generate_token(self, timestamp: int, nonce: bytes) -> bytes:
        """Generate compact authentication token"""
        message = timestamp.to_bytes(4, 'little') + nonce
        return self.hasher.hash(message)
    
    def verify_token(self, token: bytes, timestamp: int, nonce: bytes) -> bool:
        """Verify authentication token"""
        expected = self.generate_token(timestamp, nonce)
        return token == expected

# Lightweight file integrity
class CompactIntegrity:
    def __init__(self):
        self.hasher = BLAKE2s(digest_size=16)  # 128-bit checksums
    
    def checksum_file(self, filepath: str) -> bytes:
        """Compute compact file checksum"""
        hasher = BLAKE2s(digest_size=16)
        
        with open(filepath, 'rb') as f:
            # Small chunks for embedded systems
            while chunk := f.read(512):
                hasher.update(chunk)
        
        return hasher.finalize()
    
    def verify_file(self, filepath: str, expected: bytes) -> bool:
        """Verify file integrity"""
        actual = self.checksum_file(filepath)
        return actual == expected

# IoT sensor data signing
class SensorSigner:
    def __init__(self, sensor_id: str, secret: bytes):
        self.sensor_id = sensor_id
        self.secret = secret
        personalization = f"SENS{sensor_id[:4]}".encode()[:8]
        self.hasher = BLAKE2s(key=secret, personalization=personalization)
    
    def sign_reading(self, temperature: float, humidity: float, 
                    timestamp: int) -> dict:
        """Sign sensor reading"""
        # Pack data efficiently
        data = struct.pack('<ffI', temperature, humidity, timestamp)
        signature = self.hasher.hash(data)
        
        return {
            'sensor_id': self.sensor_id,
            'temperature': temperature,
            'humidity': humidity,
            'timestamp': timestamp,
            'signature': signature.hex()
        }
    
    def verify_reading(self, reading: dict) -> bool:
        """Verify signed reading"""
        data = struct.pack('<ffI', 
                          reading['temperature'],
                          reading['humidity'], 
                          reading['timestamp'])
        expected = self.hasher.hash(data)
        return expected.hex() == reading['signature']

# Memory-constrained password hashing
class LightweightPassword:
    def __init__(self, iterations=1000):
        self.iterations = iterations
    
    def hash_password(self, password: str, salt: bytes = None) -> tuple:
        """Lightweight password hashing for embedded systems"""
        if salt is None:
            salt = os.urandom(8)
        
        # Initial hash with salt
        hasher = BLAKE2s(salt=salt, personalization=b"Password")
        current = hasher.hash(password.encode())
        
        # Simple iteration (less memory than PBKDF2/Argon2)
        for i in range(self.iterations):
            hasher = BLAKE2s(key=current[:32])
            current = hasher.hash(salt + i.to_bytes(2, 'little'))
        
        return current, salt

# Merkle tree for embedded systems
class CompactMerkleTree:
    def __init__(self):
        self.hasher = BLAKE2s(digest_size=16)  # 128-bit nodes
    
    def hash_leaf(self, data: bytes) -> bytes:
        """Hash leaf node"""
        return self.hasher.hash(b"\x00" + data)
    
    def hash_internal(self, left: bytes, right: bytes) -> bytes:
        """Hash internal node"""
        return self.hasher.hash(b"\x01" + left + right)
    
    def compute_root(self, leaves: list) -> bytes:
        """Compute Merkle root with minimal memory"""
        if not leaves:
            return self.hasher.hash(b"")
        
        # Hash leaves
        current_level = [self.hash_leaf(leaf) for leaf in leaves]
        
        # Build tree level by level
        while len(current_level) > 1:
            next_level = []
            
            # Process pairs
            for i in range(0, len(current_level) - 1, 2):
                parent = self.hash_internal(
                    current_level[i], 
                    current_level[i + 1]
                )
                next_level.append(parent)
            
            # Handle odd leaf
            if len(current_level) % 2 == 1:
                next_level.append(current_level[-1])
            
            current_level = next_level
        
        return current_level[0]

Implementation Details

# BLAKE2s core operations (simplified)
class BLAKE2sCore:
    def __init__(self):
        self.h = [  # Initial hash values (32-bit)
            0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a,
            0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19
        ]
        self.t = [0, 0]  # Counter (64-bit as two 32-bit)
        self.f = [0, 0]  # Finalization flags
        
    def G(self, v, a, b, c, d, x, y):
        """BLAKE2s G function (32-bit operations)"""
        v[a] = (v[a] + v[b] + x) & 0xFFFFFFFF
        v[d] = self.rotr32(v[d] ^ v[a], 16)
        v[c] = (v[c] + v[d]) & 0xFFFFFFFF
        v[b] = self.rotr32(v[b] ^ v[c], 12)
        v[a] = (v[a] + v[b] + y) & 0xFFFFFFFF
        v[d] = self.rotr32(v[d] ^ v[a], 8)
        v[c] = (v[c] + v[d]) & 0xFFFFFFFF
        v[b] = self.rotr32(v[b] ^ v[c], 7)
    
    def compress(self, block, last=False):
        """Compression function for 32-bit words"""
        v = self.h[:] + [
            0x6a09e667, 0xbb67ae85,
            0x3c6ef372, 0xa54ff53a
        ]
        
        v[12] ^= self.t[0]
        v[13] ^= self.t[1]
        
        if last:
            v[14] ^= 0xFFFFFFFF
        
        # 10 rounds of mixing (vs 12 for BLAKE2b)
        for round in range(10):
            # Column step
            self.G(v, 0, 4, 8, 12, m[sigma[round][0]], m[sigma[round][1]])
            self.G(v, 1, 5, 9, 13, m[sigma[round][2]], m[sigma[round][3]])
            self.G(v, 2, 6, 10, 14, m[sigma[round][4]], m[sigma[round][5]])
            self.G(v, 3, 7, 11, 15, m[sigma[round][6]], m[sigma[round][7]])
            # Diagonal step
            self.G(v, 0, 5, 10, 15, m[sigma[round][8]], m[sigma[round][9]])
            self.G(v, 1, 6, 11, 12, m[sigma[round][10]], m[sigma[round][11]])
            self.G(v, 2, 7, 8, 13, m[sigma[round][12]], m[sigma[round][13]])
            self.G(v, 3, 4, 9, 14, m[sigma[round][14]], m[sigma[round][15]])
        
        # Update hash values
        for i in range(8):
            self.h[i] ^= v[i] ^ v[i + 8]
    
    def rotr32(self, x, n):
        """32-bit rotate right"""
        return ((x >> n) | (x << (32 - n))) & 0xFFFFFFFF

Security Considerations

Best Practices

  1. Output Size Selection
    • Use full 256-bit output for maximum security
    • 128-bit output acceptable for non-critical uses
    • Avoid outputs smaller than 128 bits for security
  2. Key Management
    • Generate keys using secure random source
    • Use different keys for different purposes
    • Rotate keys regularly in long-running systems
  3. Embedded Security
    • Clear sensitive data from memory after use
    • Use constant-time comparisons for MACs
    • Implement rate limiting for authentication
  4. Resource Constraints
    • Balance security with available resources
    • Consider power analysis attacks on embedded devices
    • Use appropriate iteration counts for password hashing

Common Pitfalls

# DON'T: Use very short outputs for security
blake2s_weak = BLAKE2s(digest_size=8)  # Only 64 bits!
# WRONG: Birthday attack in 2^32 operations
weak_mac = blake2s_weak.hash(data)

# DO: Use adequate output size
blake2s_secure = BLAKE2s(digest_size=16)  # 128 bits minimum
secure_mac = blake2s_secure.hash(data)

# DON'T: Use predictable personalization
device_id = "12345"
# WRONG: Predictable personalization
blake2s = BLAKE2s(personalization=device_id.encode()[:8])

# DO: Use properly formatted personalization
blake2s = BLAKE2s(personalization=b"DEV12345")  # Fixed 8 bytes

# DON'T: Ignore timing attacks in embedded systems
def verify_mac(computed, expected):
    # WRONG: Early return leaks timing information
    for i in range(len(computed)):
        if computed[i] != expected[i]:
            return False
    return True

# DO: Use constant-time comparison
def verify_mac_secure(computed, expected):
    if len(computed) != len(expected):
        return False
    result = 0
    for x, y in zip(computed, expected):
        result |= x ^ y
    return result == 0

Performance Characteristics

Benchmarks

Operation Data Size Platform Throughput Time
BLAKE2s-256 64 B ARM Cortex-M4 12.8 MB/s 5.0 μs
BLAKE2s-256 1 KB ARM Cortex-M4 45.2 MB/s 22.1 μs
BLAKE2s-256 64 B x86-32 89.6 MB/s 0.71 μs
BLAKE2s-256 1 KB x86-32 412 MB/s 2.43 μs
BLAKE2s-128 1 KB ARM Cortex-M4 46.8 MB/s 21.4 μs
Keyed Mode 1 KB ARM Cortex-M4 44.9 MB/s 22.3 μs

Memory Usage

Component RAM Usage Code Size
State Structure 64 bytes -
Working Variables 64 bytes -
Stack (typical) 128 bytes -
Code (ARM Thumb) - ~2 KB
Code (x86) - ~3 KB
Total Typical 256 bytes 2-3 KB

Performance vs Other Hash Functions

Algorithm ARM Cortex-M4 (1KB) Relative Speed
BLAKE2s 45.2 MB/s 1.00x (baseline)
SHA-256 18.7 MB/s 0.41x
SHA-1 24.3 MB/s 0.54x
MD5 31.2 MB/s 0.69x
BLAKE2b 28.9 MB/s 0.64x

Optimization Strategies

# Efficient batch processing for embedded systems
class BatchProcessor:
    def __init__(self, batch_size=16):
        self.batch_size = batch_size
        self.hasher = BLAKE2s(digest_size=16)
    
    def process_batch(self, items):
        """Process items in batches to reduce overhead"""
        results = []
        
        for i in range(0, len(items), self.batch_size):
            batch = items[i:i + self.batch_size]
            batch_hash = self.hasher.hash(b''.join(batch))
            results.append(batch_hash)
        
        return results

# Memory-efficient streaming for large data
def hash_stream_embedded(stream, chunk_size=256):
    """Hash stream with minimal memory usage"""
    hasher = BLAKE2s()
    total_bytes = 0
    
    while True:
        chunk = stream.read(chunk_size)
        if not chunk:
            break
        
        hasher.update(chunk)
        total_bytes += len(chunk)
        
        # Yield progress for UI updates
        yield total_bytes
    
    yield hasher.finalize()

# Power-efficient hashing with sleep
class PowerEfficientHasher:
    def __init__(self, power_mode='balanced'):
        self.hasher = BLAKE2s()
        self.sleep_ms = {
            'low_power': 10,
            'balanced': 1,
            'performance': 0
        }[power_mode]
    
    def hash_with_throttle(self, data, chunk_size=1024):
        """Hash data with power throttling"""
        import time
        
        for i in range(0, len(data), chunk_size):
            chunk = data[i:i + chunk_size]
            self.hasher.update(chunk)
            
            if self.sleep_ms > 0:
                time.sleep(self.sleep_ms / 1000)
        
        return self.hasher.finalize()

Use Cases

1. IoT Device Authentication

class IoTDeviceAuth:
    def __init__(self, device_secret: bytes):
        self.secret = device_secret
        self.counter = 0
    
    def generate_auth_packet(self, data: bytes) -> bytes:
        """Generate authenticated packet for IoT communication"""
        # Increment counter for replay protection
        self.counter += 1
        
        # Pack header efficiently
        header = struct.pack('<HI', 
                           0x1234,  # Protocol version
                           self.counter)
        
        # Compute MAC
        hasher = BLAKE2s(key=self.secret, digest_size=16)
        hasher.update(header)
        hasher.update(data)
        mac = hasher.finalize()
        
        # Return packet: header + data + mac
        return header + data + mac
    
    def verify_auth_packet(self, packet: bytes) -> tuple:
        """Verify and extract authenticated packet"""
        if len(packet) < 22:  # 6 (header) + 16 (MAC)
            return False, None
        
        header = packet[:6]
        data = packet[6:-16]
        mac = packet[-16:]
        
        # Verify protocol version
        version, counter = struct.unpack('<HI', header)
        if version != 0x1234:
            return False, None
        
        # Verify counter (prevent replay)
        if counter <= self.counter:
            return False, None
        
        # Verify MAC
        hasher = BLAKE2s(key=self.secret, digest_size=16)
        hasher.update(header)
        hasher.update(data)
        expected_mac = hasher.finalize()
        
        if not constant_time_compare(mac, expected_mac):
            return False, None
        
        # Update counter
        self.counter = counter
        return True, data

2. Firmware Verification

class FirmwareVerifier:
    def __init__(self, public_key: bytes):
        self.public_key = public_key
        self.chunk_size = 512  # Small chunks for embedded
    
    def compute_firmware_hash(self, firmware: bytes) -> bytes:
        """Compute firmware hash with metadata"""
        hasher = BLAKE2s(personalization=b"FW_HASH1")
        
        # Add firmware metadata
        header = struct.pack('<III',
                           len(firmware),  # Size
                           0x01020304,     # Version
                           0x20240101)     # Build date
        hasher.update(header)
        
        # Hash firmware in chunks
        for i in range(0, len(firmware), self.chunk_size):
            chunk = firmware[i:i + self.chunk_size]
            hasher.update(chunk)
        
        return hasher.finalize()
    
    def verify_firmware(self, firmware: bytes, signature: bytes) -> bool:
        """Verify firmware signature"""
        # Compute hash
        fw_hash = self.compute_firmware_hash(firmware)
        
        # Verify signature (simplified - use real crypto)
        hasher = BLAKE2s(key=self.public_key)
        expected = hasher.hash(fw_hash)
        
        return expected[:16] == signature

class SecureBootloader:
    def __init__(self):
        self.trusted_hashes = {}  # Hash -> version mapping
    
    def add_trusted_firmware(self, version: str, firmware: bytes):
        """Add trusted firmware hash"""
        hasher = BLAKE2s(digest_size=16)  # Compact hashes
        fw_hash = hasher.hash(firmware)
        self.trusted_hashes[fw_hash] = version
    
    def verify_and_boot(self, firmware: bytes) -> bool:
        """Verify firmware before booting"""
        hasher = BLAKE2s(digest_size=16)
        fw_hash = hasher.hash(firmware)
        
        if fw_hash in self.trusted_hashes:
            version = self.trusted_hashes[fw_hash]
            print(f"Booting trusted firmware v{version}")
            return True
        
        print("Firmware verification failed!")
        return False

3. Sensor Network Security

class SensorNetwork:
    def __init__(self, network_key: bytes):
        self.network_key = network_key
        self.nodes = {}
    
    def register_node(self, node_id: str) -> bytes:
        """Register sensor node and derive its key"""
        # Derive node-specific key
        hasher = BLAKE2s(key=self.network_key)
        node_key = hasher.hash(f"NODE:{node_id}".encode())
        
        self.nodes[node_id] = {
            'key': node_key,
            'sequence': 0
        }
        
        return node_key
    
    def create_sensor_packet(self, node_id: str, sensor_data: dict) -> bytes:
        """Create authenticated sensor packet"""
        if node_id not in self.nodes:
            raise ValueError("Unknown node")
        
        node = self.nodes[node_id]
        node['sequence'] += 1
        
        # Pack sensor data efficiently
        packet = struct.pack('<H', node['sequence'])  # Sequence number
        packet += struct.pack('<f', sensor_data['temperature'])
        packet += struct.pack('<f', sensor_data['humidity'])
        packet += struct.pack('<I', sensor_data['timestamp'])
        
        # Add MAC
        hasher = BLAKE2s(key=node['key'], digest_size=8)  # Short MAC
        hasher.update(packet)
        mac = hasher.finalize()
        
        return node_id.encode()[:8] + packet + mac
    
    def verify_sensor_packet(self, packet: bytes) -> dict:
        """Verify and parse sensor packet"""
        if len(packet) < 26:  # 8 + 14 + 8
            raise ValueError("Invalid packet size")
        
        node_id = packet[:8].decode().strip('\x00')
        data = packet[8:-8]
        mac = packet[-8:]
        
        if node_id not in self.nodes:
            raise ValueError("Unknown node")
        
        # Verify MAC
        node = self.nodes[node_id]
        hasher = BLAKE2s(key=node['key'], digest_size=8)
        hasher.update(data)
        expected_mac = hasher.finalize()
        
        if mac != expected_mac:
            raise ValueError("MAC verification failed")
        
        # Parse data
        seq = struct.unpack('<H', data[0:2])[0]
        
        # Verify sequence (prevent replay)
        if seq <= node['sequence']:
            raise ValueError("Replay attack detected")
        
        node['sequence'] = seq
        
        return {
            'node_id': node_id,
            'sequence': seq,
            'temperature': struct.unpack('<f', data[2:6])[0],
            'humidity': struct.unpack('<f', data[6:10])[0],
            'timestamp': struct.unpack('<I', data[10:14])[0]
        }

4. Lightweight Blockchain

class LightBlock:
    def __init__(self, index, timestamp, data, previous_hash):
        self.index = index
        self.timestamp = timestamp
        self.data = data
        self.previous_hash = previous_hash
        self.nonce = 0
        self.hash = None
    
    def compute_hash(self):
        """Compute block hash using BLAKE2s"""
        hasher = BLAKE2s(digest_size=16)  # 128-bit hashes
        
        # Pack block data
        hasher.update(struct.pack('<I', self.index))
        hasher.update(struct.pack('<I', self.timestamp))
        hasher.update(self.previous_hash)
        hasher.update(self.data.encode() if isinstance(self.data, str) else self.data)
        hasher.update(struct.pack('<I', self.nonce))
        
        return hasher.finalize()
    
    def mine_block(self, difficulty=2):
        """Simple proof of work"""
        target = b'\x00' * difficulty
        
        while True:
            self.hash = self.compute_hash()
            if self.hash[:difficulty] == target:
                break
            self.nonce += 1
            
            # Yield periodically for cooperative multitasking
            if self.nonce % 1000 == 0:
                yield self.nonce
        
        yield self.hash

class LightBlockchain:
    def __init__(self):
        self.chain = []
        self.difficulty = 2
        
        # Create genesis block
        genesis = LightBlock(0, 0, "Genesis", b'\x00' * 16)
        genesis.hash = genesis.compute_hash()
        self.chain.append(genesis)
    
    def add_block(self, data):
        """Add new block to chain"""
        previous = self.chain[-1]
        block = LightBlock(
            len(self.chain),
            int(time.time()),
            data,
            previous.hash
        )
        
        # Mine block
        for progress in block.mine_block(self.difficulty):
            if isinstance(progress, int):
                print(f"Mining... {progress} hashes")
            else:
                block.hash = progress
                break
        
        self.chain.append(block)
        return block
    
    def verify_chain(self):
        """Verify blockchain integrity"""
        for i in range(1, len(self.chain)):
            current = self.chain[i]
            previous = self.chain[i-1]
            
            # Verify hash
            if current.compute_hash() != current.hash:
                return False
            
            # Verify link
            if current.previous_hash != previous.hash:
                return False
            
            # Verify proof of work
            if current.hash[:self.difficulty] != b'\x00' * self.difficulty:
                return False
        
        return True

Comparison with Other Hash Functions

BLAKE2s vs BLAKE2b

Feature BLAKE2s BLAKE2b
Word Size 32-bit 64-bit
Output Size 1-32 bytes 1-64 bytes
Block Size 64 bytes 128 bytes
Rounds 10 12
Best Platform 32-bit, embedded 64-bit servers

BLAKE2s vs SHA-256 (Embedded)

Feature BLAKE2s SHA-256
Speed (Cortex-M4) 45.2 MB/s 18.7 MB/s
Code Size ~2 KB ~3 KB
RAM Usage 256 bytes 320 bytes
Keyed Mode Native Needs HMAC
Flexibility High Low

When to Use BLAKE2s

# Use BLAKE2s for embedded/32-bit systems
if platform == "embedded" or architecture == "32-bit":
    hasher = BLAKE2s()  # Optimized for platform

# Use BLAKE2b for servers/64-bit systems  
elif platform == "server" or architecture == "64-bit":
    hasher = BLAKE2b()  # Better performance

# Use BLAKE2s for small digests
if required_size <= 32:
    hasher = BLAKE2s(digest_size=required_size)

# Use BLAKE2s for memory-constrained environments
if available_ram < 1024:  # Less than 1KB RAM
    hasher = BLAKE2s()  # Smaller working set

Migration Guide

From MD5 (Embedded Systems)

# Before: MD5 on embedded system
import hashlib
checksum = hashlib.md5(data).digest()  # 128-bit, insecure

# After: BLAKE2s with same output size
from metamui_crypto import BLAKE2s
hasher = BLAKE2s(digest_size=16)  # 128-bit, secure
checksum = hasher.hash(data)

# Migration wrapper for gradual transition
class HashMigrator:
    def __init__(self, use_blake2s=True):
        self.use_blake2s = use_blake2s
    
    def compute_checksum(self, data):
        if self.use_blake2s:
            return BLAKE2s(digest_size=16).hash(data)
        else:
            return hashlib.md5(data).digest()

From SHA-1 (IoT Devices)

# Before: SHA-1 for IoT authentication
import hashlib
import hmac
mac = hmac.new(key, data, hashlib.sha1).digest()  # 160-bit

# After: BLAKE2s keyed mode
from metamui_crypto import BLAKE2s
hasher = BLAKE2s(key=key, digest_size=20)  # 160-bit compatible
mac = hasher.hash(data)

# Backward compatible implementation
def compute_mac(key, data, algorithm='blake2s'):
    if algorithm == 'blake2s':
        return BLAKE2s(key=key, digest_size=20).hash(data)
    elif algorithm == 'hmac-sha1':
        return hmac.new(key, data, hashlib.sha1).digest()

From CRC32 (Checksums)

# Before: CRC32 for file checksums
import zlib
crc = zlib.crc32(data)  # 32-bit, non-cryptographic

# After: BLAKE2s for secure checksums
from metamui_crypto import BLAKE2s
hasher = BLAKE2s(digest_size=4)  # 32-bit output
checksum = hasher.hash(data)

# Or use longer output for better security
hasher = BLAKE2s(digest_size=8)  # 64-bit, much more secure
checksum = hasher.hash(data)

Test Vectors

BLAKE2s-256 Test Vectors

# Test Vector 1: Empty input
blake2s = BLAKE2s()
assert blake2s.hash(b"").hex() == "69217a3079908094e11121d042354a7c1f55b6482ca1a51e1b250dfd1ed0eef9"

# Test Vector 2: "abc"
assert blake2s.hash(b"abc").hex() == "508c5e8c327c14e2e1a72ba34eeb452f37458b209ed63a294d999b4c86675982"

# Test Vector 3: One million 'a's
data = b"a" * 1000000
assert blake2s.hash(data).hex() == "bec0c0e6cde5b67acb73b81f79a67a4079ae1c60dac9d2661af18e9f8b50dfa5"

# Test Vector 4: "The quick brown fox jumps over the lazy dog"
message = b"The quick brown fox jumps over the lazy dog"
assert blake2s.hash(message).hex() == "606beeec743ccbeff6cbcdf5d5302aa855c256c29b88c8ed331ea1a6bf3c8812"

BLAKE2s Keyed Mode Test Vectors

# Test Vector 5: Keyed hashing
key = bytes.fromhex("000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f")
blake2s_keyed = BLAKE2s(key=key)

# Empty input with key
assert blake2s_keyed.hash(b"").hex() == "48a8997da407876b3d79c0d92325ad3b89cbb754d86ab71aee047ad345fd2c49"

# "abc" with key
assert blake2s_keyed.hash(b"abc").hex() == "c19012cc2aaf0dc3d8e5c45a1b79114d2df42abb2a410bf54be09e891af06ff8"

BLAKE2s-128 Test Vectors

# Test Vector 6: BLAKE2s-128
blake2s_128 = BLAKE2s(digest_size=16)

# Empty input
assert blake2s_128.hash(b"").hex() == "64550d6ffe2c0a01a14aba1eade0200c"

# "abc"
assert blake2s_128.hash(b"abc").hex() == "aa4938119b1dc7b87cbad0ffd200d0ae"

# With personalization
blake2s_personal = BLAKE2s(digest_size=16, personalization=b"ZcashSig")
assert blake2s_personal.hash(b"").hex() == "f9a8a6843a5ba3db2a7977f9e112f8e8"

Incremental Hashing Test

# Test Vector 7: Incremental vs one-shot
data = b"The quick brown fox jumps over the lazy dog"

# One-shot
blake2s = BLAKE2s()
one_shot = blake2s.hash(data)

# Incremental
hasher = BLAKE2s()
hasher.update(b"The quick brown ")
hasher.update(b"fox jumps over ")
hasher.update(b"the lazy dog")
incremental = hasher.finalize()

assert one_shot == incremental

📋 Standards & References

🏛️ RFC 7693

The BLAKE2 Cryptographic Hash and MAC - Official specification

📄 BLAKE2 Paper

Original academic specification and cryptanalysis

💾 Reference Code

Official BLAKE2 reference implementations

🔒 CBOR Security

RFC 8152 - CBOR Object Signing uses BLAKE2