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The Desi Book

Crypto

Crypto Module¶

The crypto module provides cryptographic hashing, HMAC, token generation, and password hashing — all with zero external dependencies.

Import¶

import crypto

API Reference¶

Hashing¶

Function	Returns	Description
`sha256(data)`	`str`	SHA-256 hex digest
`sha512(data)`	`str`	SHA-512 hex digest
`md5(data)`	`str`	MD5 hex digest
`sha1(data)`	`str`	SHA-1 hex digest

HMAC¶

Function	Returns	Description
`hmac_sha256(key, msg)`	`str`	HMAC-SHA256 hex digest

Comparison¶

Function	Returns	Description
`constant_time_equal(a, b)`	`bool`	Timing-safe string comparison

Token Generation¶

Function	Returns	Description
`token_hex(n)`	`str`	Generate `n` random hex bytes (2n chars)

Password Hashing¶

Function	Returns	Description
`hash_password(password)`	`str`	Hash password with random salt (SHA-256)
`verify_password(password, hash)`	`bool`	Verify password against stored hash

Usage Examples¶

Basic Hashing¶

import crypto

def main() -> int:
    let data = "Hello, Desi!"

    print(f"SHA-256: {crypto.sha256(data)}")
    print(f"SHA-512: {crypto.sha512(data)}")
    print(f"MD5: {crypto.md5(data)}")
    print(f"SHA-1: {crypto.sha1(data)}")
    0

API Authentication¶

import crypto

def sign_request(secret: str, payload: str) -> str:
    return crypto.hmac_sha256(secret, payload)

def verify_signature(secret: str, payload: str, signature: str) -> bool:
    let expected = crypto.hmac_sha256(secret, payload)
    return crypto.constant_time_equal(expected, signature)

Session Tokens¶

import crypto

# Generate a 32-byte (64-character) random token
let session_token = crypto.token_hex(32)
print(f"Session: {session_token}")

Password Storage¶

import crypto

# Registration: hash the password
let hashed = crypto.hash_password("mypassword123")
# Store `hashed` in database

# Login: verify the password
let valid = crypto.verify_password("mypassword123", hashed)
if valid:
    print("Login successful!")

[!WARNING] The md5() and sha1() functions are provided for compatibility only. For security-sensitive applications, always use sha256() or sha512().

[!NOTE] Password hashing uses SHA-256 with a random salt. The hash format is salt:hash where both are hex-encoded.

See Also¶

Hash Module — Lower-level hash functions
UUID Module — UUID generation