Cryptography

What Is Cryptography?

Cryptography is the science of protecting information by converting it into a form that only authorized parties can read, using mathematical techniques and computation. It also verifies that data has not been altered.

In a basic encryption process, plaintext (readable data) is transformed into ciphertext (unreadable output). Only someone holding the right decryption key can reverse the process, which allows sensitive data to travel safely even over unsecured networks. The strength of the protection depends on what the data requires, and securing a cryptocurrency network demands far more than protecting an everyday file.

The Building Blocks of Modern Cryptography

Modern cryptography covers several major areas of study. 

• Symmetric encryption: uses a single shared key to both encrypt and decrypt data, which makes it fast but requires a secure way to share that key. 
• Asymmetric encryption: uses a matched pair of keys. This comprises a public key that anyone can see and a private key that only the owner knows. 
• Hash functions: produce a fixed fingerprint of any input, so even a small change to the data produces a completely different result.

For example, if Alice sends two bitcoins to Bob, she creates a transaction that unlocks her unspent funds and assigns them to Bob's address. She can only do so by providing a valid digital signature, which proves she authorizes the movement of the funds. This allows the network to validate the transfer and prevents those same coins from being double-spent.

Cryptography in Bitcoin and Blockchain Networks

Quantum Computing and the Future of Cryptography

Organizations worldwide are now planning gradual migrations so that today's encrypted data stays secure as quantum hardware matures.

Regulators are watching this transition closely. In September 2026, the Joint Committee of the European Supervisory Authorities (EBA, EIOPA, and ESMA) warned that quantum computing could threaten the cryptography protecting blockchains, communications, and databases, potentially before commercially viable quantum computers even exist. No quantum machine capable of breaking Bitcoin cryptography is known to exist today, but the field treats the migration as a long-term priority.

What Cryptography Means for Users