Elliptic Curve Integrated Encryption Scheme for secp256k1/curve25519 in Python.

Other language versions:

• TypeScript
• Rust
• Golang
• WASM
• Java
• Dart

You can also check a web backend demo.

pip install eciespy

Or pip install 'eciespy[eth]' to install eth-keys as well.

>>> from ecies.keys import PrivateKey >>> from ecies import encrypt, decrypt >>> data = 'hello world🌍'.encode() >>> sk = PrivateKey('secp256k1') >>> sk_bytes = sk.secret # bytes >>> pk_bytes = sk.public_key.to_bytes(True) # bytes >>> decrypt(sk_bytes, encrypt(pk_bytes, data)).decode() 'hello world🌍' >>> sk_hex = sk.to_hex() # hex str >>> pk_hex = sk.public_key.to_hex(True) # hex str >>> decrypt(sk_hex, encrypt(pk_hex, data)).decode() 'hello world🌍'

>>> from ecies.keys import PrivateKey >>> from ecies import encrypt, decrypt >>> from ecies.config import ECIES_CONFIG >>> ECIES_CONFIG.elliptic_curve = 'x25519' # or 'ed25519' >>> data = 'hello world🌍'.encode() >>> sk = PrivateKey('x25519') # or 'ed25519' >>> decrypt(sk.secret, encrypt(sk.public_key.to_bytes(), data)).decode() 'hello world🌍'

Or just use a builtin command eciespy in your favorite command line.

Parameters:

• receiver_pk - Receiver's public key (hex str or bytes)
• data - Data to encrypt
• config - Optional configuration object

Returns: bytes

Parameters:

• receiver_sk - Receiver's private key (hex str or bytes)
• data - Data to decrypt
• config - Optional configuration object

Returns: bytes

$ eciespy -h usage: eciespy [-h] [-e] [-d] [-g] [-k KEY] [-c {secp256k1,x25519,ed25519}] [-D [DATA]] [-O [OUT]] Elliptic Curve Integrated Encryption Scheme for secp256k1/curve25519 in Python options:  -h, --help show this help message and exit  -e, --encrypt encrypt with public key, exclusive with -d  -d, --decrypt decrypt with private key, exclusive with -e  -g, --generate generate key pair, for secp256k1, ethereum public key and address will be printed  -k, --key KEY public or private key file  -c, --curve {secp256k1,x25519,ed25519}  elliptic curve, default: secp256k1  -D, --data [DATA] file to encrypt or decrypt, if not specified, it will read from stdin  -O, --out [OUT] encrypted or decrypted file, if not specified, it will write to stdout

$ eciespy -g Private: 0x95d3c5e483e9b1d4f5fc8e79b2deaf51362980de62dbb082a9a4257eef653d7d Public: 0x98afe4f150642cd05cc9d2fa36458ce0a58567daeaf5fde7333ba9b403011140a4e28911fcf83ab1f457a30b4959efc4b9306f514a4c3711a16a80e3b47eb58b Address: 0x47e801184B3a8ea8E6A4A7A4CFEfEcC76809Da72

$ echo '0x95d3c5e483e9b1d4f5fc8e79b2deaf51362980de62dbb082a9a4257eef653d7d' > sk $ echo '0x98afe4f150642cd05cc9d2fa36458ce0a58567daeaf5fde7333ba9b403011140a4e28911fcf83ab1f457a30b4959efc4b9306f514a4c3711a16a80e3b47eb58b' > pk $ echo 'hello ecies' | eciespy -e -k pk | eciespy -d -k sk hello ecies $ echo 'data to encrypt' > data $ eciespy -e -k pk -D data -O enc_data $ eciespy -d -k sk -D enc_data data to encrypt $ rm sk pk data enc_data

Following configurations are available.

• Elliptic curve: secp256k1 or curve25519 (x25519/ed25519)
• Ephemeral key format in the payload: compressed or uncompressed (only for secp256k1)
• Shared elliptic curve key format in the key derivation: compressed or uncompressed (only for secp256k1)
• Symmetric cipher algorithm: AES-256-GCM or XChaCha20-Poly1305
• Symmetric nonce length: 12 or 16 bytes (only for AES-256-GCM)

For compatibility, make sure different applications share the same configuration.

EllipticCurve = Literal["secp256k1", "x25519", "ed25519"] SymmetricAlgorithm = Literal["aes-256-gcm", "xchacha20"] NonceLength = Literal[12, 16] # only for aes-256-gcm, xchacha20 will always be 24 @dataclass() class Config: elliptic_curve: EllipticCurve = "secp256k1" is_ephemeral_key_compressed: bool = False is_hkdf_key_compressed: bool = False symmetric_algorithm: SymmetricAlgorithm = "aes-256-gcm" symmetric_nonce_length: NonceLength = 16 @property def ephemeral_key_size(self): if self.elliptic_curve == "secp256k1": return ( COMPRESSED_PUBLIC_KEY_SIZE if self.is_ephemeral_key_compressed else UNCOMPRESSED_PUBLIC_KEY_SIZE ) elif self.elliptic_curve in ("x25519", "ed25519"): return CURVE25519_PUBLIC_KEY_SIZE else: raise NotImplementedError ECIES_CONFIG = Config()

On ECIES_CONFIG.elliptic_curve = "x25519" or "ed25519", x25519 (key exchange function on curve25519) or ed25519 (signature algorithm on curve25519) will be used for key exchange instead of secp256k1.

In this case, the payload would always be: 32 Bytes + Ciphered.

If you don't know how to choose between x25519 and ed25519, just use the dedicated key exchange function x25519 for efficiency.

Because any 32-byte data is a valid curve25519 public key, the payload would seem random. This property is excellent for circumventing censorship by adversaries.

On is_ephemeral_key_compressed = True, the payload would be like: 33 Bytes + Ciphered instead of 65 Bytes + Ciphered.

On is_hkdf_key_compressed = True, the hkdf key would be derived from ephemeral public key (compressed) + shared public key (compressed) instead of ephemeral public key (uncompressed) + shared public key (uncompressed).

On symmetric_algorithm = "xchacha20", plaintext data would be encrypted with XChaCha20-Poly1305.

On symmetric_nonce_length = 12, then the nonce of AES-256-GCM would be 12 bytes. XChaCha20-Poly1305's nonce is always 24 bytes.

For compatibility with other ecies libraries, start with the default (secp256k1 with AES-256-GCM).

For speed and security, pick x25519 with XChaCha20-Poly1305.

See DETAILS.md.

See CHANGELOG.md.