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Quickstart

Get started with qcrypto in 5 minutes.

Install

pip install qcrypto

Generate Your First Keypair

qcrypto gen-key

Output: 

Generated Kyber768 keypair:
  Public key:  /home/user/.qcrypto/kem/public.key
  Fingerprint: a1b2c3d4e5f67890...
  Private key: /home/user/.qcrypto/kem/private.key


from qcrypto import KyberKEM, key_fingerprint

kem = KyberKEM("Kyber768")
keys = kem.generate_keypair()

print(f"Fingerprint: {key_fingerprint(keys.public_key)}")

Encrypt a Message

# Create a test file
echo "Secret message" > message.txt

# Encrypt it
qcrypto encrypt --in message.txt --out message.enc

from qcrypto import KyberKEM, encrypt

# Load the public key
pub = KyberKEM.load_public_key("~/.qcrypto/kem/public.key")

# Encrypt
plaintext = b"Secret message"
ciphertext = encrypt(pub, plaintext)

print(f"Ciphertext size: {len(ciphertext)} bytes")

Decrypt the Message

qcrypto decrypt --in message.enc --out message.dec.txt
cat message.dec.txt
# Secret message

from qcrypto import KyberKEM, decrypt

# Load the private key
priv = KyberKEM.load_private_key("~/.qcrypto/kem/private.key")

# Decrypt
plaintext = decrypt(priv, ciphertext)
print(plaintext.decode())  # "Secret message"

Sign a Document

# Generate signature keys
qcrypto sig-gen-key --alg Dilithium3

# Sign
qcrypto sign --in document.pdf --out document.sig

# Verify
qcrypto verify --in document.pdf --sig document.sig
# OK: signature valid

from qcrypto import SignatureScheme

# Create scheme and keys
scheme = SignatureScheme("Dilithium3")
keys = scheme.generate_keypair()

# Sign
document = open("document.pdf", "rb").read()
signature = scheme.sign(keys.secret_key, document)

# Verify
valid = scheme.verify(keys.public_key, document, signature)
print(f"Valid: {valid}")  # True

Protect Keys with a Passphrase

# Generate passphrase-protected keys
qcrypto gen-key --pass

# The CLI prompts for passphrase
# Passphrase: ********

# Decrypt requires the passphrase
qcrypto decrypt --pass --in secret.enc --out secret.txt

Use ASCII-Armored Keys

Armored keys are human-readable and safe for copy/paste:

qcrypto gen-key --armored
cat ~/.qcrypto/kem/public.key

Output: 

-----BEGIN QCRYPTO PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA...
(base64 content)
-----END QCRYPTO PUBLIC KEY-----

Next Steps