Crypto

BLS Cryptography

BLS signature implementation for Saline SDK.

This module provides BLS signature functionality using the BLS12-381 curve, following the IETF BLS signature standard draft v4 (basic scheme).

This implementation matches the implementation in Saline exactly: - Uses raw message bytes for signing (no pre-hashing) - Uses BLS_SIG_BLS12381G2_XMD:SHA-256_SSWU_RO_NUL_ as domain parameter - Follows the same serialization format

class saline_sdk.crypto.bls.BLS[source]

Bases: object

BLS signature implementation using the basic scheme.

class PrivateKey

Bases: pybind11_object

aggregate(self: List[blspy.PrivateKey]) → blspy.PrivateKey

from_bytes(self: buffer) → blspy.PrivateKey

get_g1(self: blspy.PrivateKey) → bls::G1Element

PRIVATE_KEY_SIZE = 32

static aggregate_signatures(signatures)[source]

Aggregate multiple BLS signatures.

Parameters:: signatures (list[bytes]) – List of signatures in compressed form
Return type:: bytes
Returns:: Aggregated signature in compressed form
Raises:: ValueError – If aggregation fails

static sign(sk, message, dst=None)[source]

Sign a message using BLS signature scheme.

Parameters:

sk (Union[bytes, PrivateKey]) – Private key (bytes or PrivateKey object)
message (bytes) – Message to sign (raw bytes, NOT pre-hashed)
dst (Optional[bytes]) – Domain separation tag (default: SALINE_DOMAIN)

Return type:

G2Element

Returns:

Signature in compressed form

Raises:

ValueError – If signing fails

Note

This matches the implementation exactly: - Signs raw message bytes directly (no pre-hashing) - Uses BLS_SIG_BLS12381G2_XMD:SHA-256_SSWU_RO_NUL_ domain parameter

static sk_to_pk(sk)[source]

Convert private key to public key bytes.

Parameters:: sk (Union[bytes, PrivateKey]) – Private key (bytes or PrivateKey object)
Returns:: Public key in compressed form
Return type:: bytes
Raises:: ValueError – If conversion fails

static verify(pk_bytes, message, signature_bytes)[source]

Verify a message signature using a public key.

Parameters:

pk_bytes (bytes) – Public key bytes to verify with
message (bytes) – Message that was signed
signature_bytes (bytes) – Signature to verify

Return type:

bool

Returns:

True if signature is valid, False otherwise

static verify_aggregate(signature, messages, public_keys)[source]

Verify an aggregate signature.

Parameters:

signature (bytes) – Aggregate signature in compressed form
messages (list[bytes]) – List of original messages (raw bytes, NOT pre-hashed)
public_keys (list[bytes]) – List of public keys in compressed form

Return type:

bool

Returns:

True if aggregate signature is valid

Note

BasicSchemeMPL.aggregate_verify() internally uses the domain parameter “BLS_SIG_BLS12381G2_XMD:SHA-256_SSWU_RO_NUL_” which matches Saline’s.

Key Derivation

saline_sdk.crypto.key_derivation.debug_print(*args, **kwargs)[source]: Helper function for debug printing

saline_sdk.crypto.key_derivation.derive_child_SK(parent_SK, index)[source]

Derive a child secret key from a parent secret key and index. parent_SK is in big-endian format (I2OSP).

Return type:

bytes

Parameters:

parent_SK (bytes)
index (int)

saline_sdk.crypto.key_derivation.derive_key_from_path(seed, path='m/0')[source]

Derive a key from a seed and path. Path format: “m/0” for first child of master key.

Return type:

bytes

Parameters:

seed (bytes)
path (str)

saline_sdk.crypto.key_derivation.derive_master_SK(seed)[source]

Derive master secret key from seed.

Return type:: bytes
Parameters:: seed (bytes)

saline_sdk.crypto.key_derivation.hkdf_expand(prk, info, length=32)[source]

HKDF-Expand (RFC5869) using SHA-256.

Return type:

bytes

Parameters:

prk (bytes)
info (bytes)
length (int)

saline_sdk.crypto.key_derivation.hkdf_extract(salt, ikm)[source]

HKDF-Extract (RFC5869) using SHA-256.

Return type:

bytes

Parameters:

salt (bytes)
ikm (bytes)

saline_sdk.crypto.key_derivation.main()[source]

saline_sdk.crypto.key_derivation.parent_SK_to_lamport_PK(parent_SK, index)[source]

Generate compressed Lamport public key from parent SK.

Return type:

bytes

Parameters:

parent_SK (bytes)
index (int)

Crypto Module Interface

Saline SDK Crypto Module

This module provides cryptographic functionality for the Saline SDK, including: - BLS key derivation (EIP-2333) - BLS signatures - Signature verification - Signature aggregation - Public key operations

class saline_sdk.crypto.BLS[source]

Bases: object

BLS signature implementation using the basic scheme.

class PrivateKey

Bases: pybind11_object

aggregate(self: List[blspy.PrivateKey]) → blspy.PrivateKey

from_bytes(self: buffer) → blspy.PrivateKey

get_g1(self: blspy.PrivateKey) → bls::G1Element

PRIVATE_KEY_SIZE = 32

static aggregate_signatures(signatures)[source]

Aggregate multiple BLS signatures.

Parameters:: signatures (list[bytes]) – List of signatures in compressed form
Return type:: bytes
Returns:: Aggregated signature in compressed form
Raises:: ValueError – If aggregation fails

static sign(sk, message, dst=None)[source]

Sign a message using BLS signature scheme.

Parameters:

sk (Union[bytes, PrivateKey]) – Private key (bytes or PrivateKey object)
message (bytes) – Message to sign (raw bytes, NOT pre-hashed)
dst (Optional[bytes]) – Domain separation tag (default: SALINE_DOMAIN)

Return type:

G2Element

Returns:

Signature in compressed form

Raises:

ValueError – If signing fails

Note

This matches the implementation exactly: - Signs raw message bytes directly (no pre-hashing) - Uses BLS_SIG_BLS12381G2_XMD:SHA-256_SSWU_RO_NUL_ domain parameter

static sk_to_pk(sk)[source]

Convert private key to public key bytes.

Parameters:: sk (Union[bytes, PrivateKey]) – Private key (bytes or PrivateKey object)
Returns:: Public key in compressed form
Return type:: bytes
Raises:: ValueError – If conversion fails

static verify(pk_bytes, message, signature_bytes)[source]

Verify a message signature using a public key.

Parameters:

pk_bytes (bytes) – Public key bytes to verify with
message (bytes) – Message that was signed
signature_bytes (bytes) – Signature to verify

Return type:

bool

Returns:

True if signature is valid, False otherwise

static verify_aggregate(signature, messages, public_keys)[source]

Verify an aggregate signature.

Parameters:

signature (bytes) – Aggregate signature in compressed form
messages (list[bytes]) – List of original messages (raw bytes, NOT pre-hashed)
public_keys (list[bytes]) – List of public keys in compressed form

Return type:

bool

Returns:

True if aggregate signature is valid

Note

BasicSchemeMPL.aggregate_verify() internally uses the domain parameter “BLS_SIG_BLS12381G2_XMD:SHA-256_SSWU_RO_NUL_” which matches Saline’s.

saline_sdk.crypto.derive_child_SK(parent_SK, index)[source]

Derive a child secret key from a parent secret key and index. parent_SK is in big-endian format (I2OSP).

Return type:

bytes

Parameters:

parent_SK (bytes)
index (int)

saline_sdk.crypto.derive_key_from_path(seed, path='m/0')[source]

Derive a key from a seed and path. Path format: “m/0” for first child of master key.

Return type:

bytes

Parameters:

seed (bytes)
path (str)

saline_sdk.crypto.derive_master_SK(seed)[source]

Derive master secret key from seed.

Return type:: bytes
Parameters:: seed (bytes)