LegacyEncryption

Legacy encryption utilities for backward compatibility.

This module provides deprecated encryption functionality maintained for backward compatibility with older versions of the SDK. For new implementations, use the human_protocol_sdk.encryption module instead.

Warning

This module is deprecated and will be removed in a future version. Please migrate to human_protocol_sdk.encryption.Encryption and human_protocol_sdk.encryption.EncryptionUtils.

Example

# Deprecated - for backward compatibility only
from human_protocol_sdk.legacy_encryption import LegacyEncryption

# Recommended - use this instead
from human_protocol_sdk.encryption import Encryption

DecryptionError

Bases: Exception

Exception raised when a message could not be decrypted.

Encryption

Encryption class specialized in encrypting and decrypting byte strings using ECIES.

This class implements Elliptic Curve Integrated Encryption Scheme (ECIES) using SECP256K1 elliptic curve, AES256 cipher, and HMAC-SHA-256-32.

Attributes:

Name	Type	Description
ELLIPTIC_CURVE	EllipticCurve	SECP256K1 elliptic curve definition.
KEY_LEN	int	Key length for ECIES (32 bytes for AES256 and HMAC-SHA-256-32).
CIPHER		AES cipher algorithm definition.
MODE		CTR cipher mode definition.
PUBLIC_KEY_LEN	int	Length of public keys in uncompressed form (64 bytes).

decrypt

decrypt(data, private_key, shared_mac_data=b'')

Decrypt data using ECIES method with the given private key.

The decryption process follows these steps: 1. Extract ephemeral public key R from message 2. Generate shared secret using ECDH: ecdhAgree(privateKey, R) 3. Derive encryption and MAC keys from shared secret 4. Verify authentication tag 5. Decrypt ciphertext using AES256-CTR

Parameters:

Name	Type	Description	Default
data	bytes	Encrypted message in ECIES format.	required
private_key	PrivateKey	Private key to decrypt the data.	required
shared_mac_data	bytes	Additional data used in MAC computation. Defaults to empty bytes.	b''

Returns:

Type	Description
bytes	Decrypted plaintext data.

Raises:

Type	Description
DecryptionError	If ECIES header is invalid, tag verification fails, key exchange fails, or decryption fails.

Example

from human_protocol_sdk.legacy_encryption import Encryption
from eth_keys import datatypes

private_key_hex = "9822f95dd945e373300f8c8459a831846eda97f314689e01f7cf5b8f1c2298b3"
encrypted_hex = "0402f48d28d29ae3d681e4cbbe499be0803c2a9d94534d0a4501ab79fd531183fbd837a021c1c117f47737e71c430b9d33915615f68c8dcb5e2f4e4dda4c9415d20a8b5fad9770b14067f2dd31a141a8a8da1f56eb2577715409dbf3c39b9bfa7b90c1acd838fe147c95f0e1ca9359a4cfd52367a73a6d6c548b492faa"

private_key = datatypes.PrivateKey(bytes.fromhex(private_key_hex))
encryption = Encryption()
decrypted = encryption.decrypt(bytes.fromhex(encrypted_hex), private_key)

encrypt

encrypt(data, public_key, shared_mac_data=b'')

Encrypt data using ECIES method with the given public key.

The encryption process follows these steps: 1. Generate random ephemeral private key r 2. Generate shared secret using ECDH key agreement 3. Derive encryption and MAC keys from shared secret 4. Generate ephemeral public key R = r*G 5. Encrypt data using AES256-CTR 6. Generate authentication tag using HMAC-SHA256 7. Return: 0x04 || R || IV || ciphertext || tag

Parameters:

Name	Type	Description	Default
data	bytes	Data to be encrypted.	required
public_key	PublicKey	Public key to encrypt data for.	required
shared_mac_data	bytes	Additional data to include in MAC computation. Defaults to empty bytes.	b''

Returns:

Type	Description
bytes	Encrypted message in ECIES format.

Raises:

Type	Description
DecryptionError	If key exchange fails or public key is invalid.

Example

from human_protocol_sdk.legacy_encryption import Encryption
from eth_keys import datatypes

public_key_hex = "0a1d228684bc8c8c7611df3264f04ebd823651acc46b28b3574d2e69900d5e34f04a26cf13237fa42ab23245b58060c239b356b0a276f57e8de1234c7100fcf9"
public_key = datatypes.PublicKey(bytes.fromhex(public_key_hex))

encryption = Encryption()
encrypted = encryption.encrypt(b'your message', public_key)

generate_private_key

generate_private_key()

Generate a new SECP256K1 private key.

Returns:

Type	Description
PrivateKey	Newly generated SECP256K1 private key.

Example

from human_protocol_sdk.legacy_encryption import Encryption

encryption = Encryption()
private_key = encryption.generate_private_key()

generate_public_key staticmethod

generate_public_key(private_key)

Generate a public key from the given private key.

Parameters:

Name	Type	Description	Default
private_key	bytes	Private key bytes to derive the public key from.	required

Returns:

Type	Description
PublicKey	Public key object corresponding to the private key.

Example

from human_protocol_sdk.legacy_encryption import Encryption

private_key_hex = "9822f95dd945e373300f8c8459a831846eda97f314689e01f7cf5b8f1c2298b3"
public_key = Encryption.generate_public_key(bytes.fromhex(private_key_hex))

is_encrypted staticmethod

is_encrypted(data)

Check whether data is already encrypted by verifying ECIES header.

Parameters:

Name	Type	Description	Default
data	bytes	Data to be checked for encryption.	required

Returns:

Type	Description
bool	True if data has valid ECIES header (starts with 0x04), False otherwise.

Example

from human_protocol_sdk.legacy_encryption import Encryption

encrypted_hex = "0402f48d28d29ae3d681e4cbbe499be0803c2a9d94534d0a4501ab79fd531183fbd837a021c1c117f47737e71c430b9d33915615f68c8dcb5e2f4e4dda4c9415d20a8b5fad9770b14067f2dd31a141a8a8da1f56eb2577715409dbf3c39b9bfa7b90c1acd838fe147c95f0e1ca9359a4cfd52367a73a6d6c548b492faa"
is_encrypted = Encryption.is_encrypted(bytes.fromhex(encrypted_hex))

InvalidPublicKey

Bases: Exception

Exception raised when converting bytes into an elliptic curve public key fails.