Practice Arena

Python Coding Challenges

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925 challenges 556 easy 323 medium 46 hard
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Cryptography & Hashing easy

SHA256 Hash String

Write a function that returns the SHA256 hexadecimal digest of a given string.

hashing sha256 hashlib
+5 pts 5m
Cryptography & Hashing easy

Compute SHA-1 Hash String

Write a function that returns the SHA-1 hash of a string as a 40-character hex string.

sha1 hashlib hashing
+10 pts 15m
Cryptography & Hashing easy

Constant Time Compare

Write a function that compares two strings without leaking length or content via timing.

constant-time security comparison
+10 pts 15m
Cryptography & Hashing easy

Verify HMAC signature

Implement a function that verifies an HMAC-SHA256 signature for a message and key.

hmac hashlib security
+10 pts 15m
Cryptography & Hashing easy

Password Salt Hash

Implement a function that returns a secure salted SHA-256 password hash with a deterministic format.

hashlib sha256 security
+8 pts 12m
Cryptography & Hashing easy

SHA1 Hash String

Implement a function that returns the SHA1 hexadecimal digest of an input string.

sha1 hashlib hashing
+10 pts 15m
Cryptography & Hashing easy

XOR Cipher Encode

Implement the XOR cipher: encode a string by XORing each character with a key character.

xor encryption strings
+10 pts 10m
Cryptography & Hashing easy

Constant time compare

Write a function that compares two strings in constant time to avoid timing attacks.

timing-safe security strings
+8 pts 10m
Cryptography & Hashing easy

Compute SHA256 Hash String

Implement a function that returns the SHA-256 hex digest of a given input string.

sha256 hashing hashlib
+8 pts 10m
Cryptography & Hashing easy

Verify HMAC signature

Implement a function that verifies an HMAC-SHA256 signature for a given message and secret key.

hmac sha256 security
+10 pts 15m

Showing 1–10 of 10 challenges · Cryptography & Hashing

Cryptography & Hashing — Python coding challenges

What you will find here

This page lists cryptography & hashing challenges — real Python problems you solve in the browser IDE with instant test feedback. Each challenge includes a clear brief, starter code, and automated checks.

Challenges vs tutorials and quizzes

Challenges test what you can build under constraints. For guided teaching, use our Python tutorials. For quick checks, try quizzes or copy snippets from code samples.