Hashing vs Encryption vs Encoding

Subtitle: Three words. Three jobs.

• Left column - HASHING:
• One way. No key. No undo.
• Same input, same digest
• Fixed length output
• Verify, never recover
• SHA-256, bcrypt, Argon2id

• Middle column - ENCRYPTION:
• Two way. Needs a key.
• Same input, new ciphertext
• Undo only with the key
• Hide data from others
• AES-GCM, RSA, ChaCha20

• Right column - ENCODING:
• Two way. No key at all.
• Not security. Just format.
• Anyone can reverse it
• Move data safely
• Base64, URL, hex, UTF-8

• Simple difference:
• Hash = a fingerprint
• Encrypt = a locked box
• Encode = a new alphabet

Use it when - HASHING: passwords, file integrity, signatures

Use it when - ENCRYPTION: secrets in transit or at rest Use it when - ENCODING: binary in JSON, URLs, email

Sticky note - Common beginner mistake:

Base64 is not encryption. It hides nothing; anyone decodes it in one line. And never encrypt a password when you only need to verify it - hash it.