winternitz package¶

Submodules¶

winternitz.signatures module¶

class winternitz.signatures.AbstractOTS[source]¶

Bases: object

OTS base class

Every class implementing OTS schemes in this package should implement the functions defined in this base class

sign() → dict[source]¶

Sign a message

This function will create a valid signature for a message on success

Parameters: message – Encoded message to sign

Returns:

A dictionary containing the fingerprint of the message, which was created using the hash function that was specified during initialization of this object, the signature and a public key to verify the signature. Structure:

{
    "w":            winternitz parameter (Type: int),
    "fingerprint":  message hash (Type: bytes),
    "hashalgo":     hash algorithm (Type: str),
    "digestsize":   hash byte count (Type: int),
    "pubkey":       public key (Type: List[bytes]),
    "signature":    signature (Type: List[bytes])
}

verify(signature: List[bytes]) → bool[source]¶

Verify a message

Verify whether a signature is valid for a message

Parameters:	message – Encoded message to verify signature – Signature that will be used to verify the message
Returns:	Whether the verification succeded

class winternitz.signatures.WOTS(w: int = 16, hashfunction: Callable = <function openssl_sha512>, digestsize: int = 512, privkey: Optional[List[bytes]] = None, pubkey: Optional[List[bytes]] = None)[source]¶

Bases: winternitz.signatures.AbstractOTS

Winternitz One-Time-Signature

Fully configurable class in regards to Winternitz paramter, hash function, private key and public key

__init__(w: int = 16, hashfunction: Callable = <function openssl_sha512>, digestsize: int = 512, privkey: Optional[List[bytes]] = None, pubkey: Optional[List[bytes]] = None) → None[source]¶

Initialize WOTS object

Define the parameters required to sign and verify a message

Parameters:

w – The Winternitz parameter. A higher value reduces the space complexity, but increases the time complexity. It must be greater than 1 but less or equal than \(2^{digestsize}\). To get the best space to time complexity ratio, choose a value that is a power of two.
hashfunction – The hashfunction which will be used to derive signatures and public keys. Specify a function which takes bytes as an argument and returns bytes that represent the hash.
digestsize – The number of bits that will be emitted by the specified hash function.
privkey – The private key to be used for signing operations. Leave None if it should be generated. In this case it will be generated when it is required.
pubkey – The public key to be used for verifying signatures. Do not specify it if a private key was specified or if it should be derived. It will be derived when it is required.

digestsize¶

Digest size getter

Get the digest size of the hash function

Returns:	Digest size of the hash function

hashfunction¶

Hash function getter

Get a reference to the current hash function

Returns:	Reference to hash function

privkey¶

Private key getter

Get a copy of the private key

Returns:	Copy of the private key

pubkey¶

Public key getter

Get a copy of the public key

Returns:	Copy of the public key

sign(message: bytes) → dict[source]¶

Sign a message

This function will create a valid signature for a message on success

Parameters: message – Encoded message to sign

Returns:

A dictionary containing the fingerprint of the message, which was created using the hash function that was specified during initialization of this object, the signature and a public key to verify the signature. Structure:

{
    "w":            winternitz parameter (Type: int),
    "fingerprint":  message hash (Type: bytes),
    "hashalgo":     hash algorithm (Type: str),
    "digestsize":   hash byte count (Type: int),
    "pubkey":       public key (Type: List[bytes]),
    "signature":    signature (Type: List[bytes])
}

slots = ['__weakref__', '__w', '__hashfunction', '__digestsize', '__privkey', '__pubkey', '__msg_key_count', '__cs_key_count', '__key_count']¶

verify(message: bytes, signature: List[bytes]) → bool[source]¶

Verify a message

Verify whether a signature is valid for a message

Parameters:	message – Encoded message to verify signature – Signature that will be used to verify the message
Returns:	Whether the verification succeded

w¶

Winternitz parameter getter

Get the Winternitz parameter

Returns:	Winternitz parameter

class winternitz.signatures.WOTSPLUS(w: int = 16, hashfunction: Callable = <function openssl_sha256>, prf: Callable = <function hmac_openssl_sha256>, digestsize: int = 256, seed: Optional[bytes] = None, privkey: Optional[List[bytes]] = None, pubkey: Optional[List[bytes]] = None)[source]¶

Bases: winternitz.signatures.WOTS

Winternitz One-Time-Signature Plus

Fully configurable class in regards to Winternitz paramter, hash function, pseudo random function, seed, private key and public key

__init__(w: int = 16, hashfunction: Callable = <function openssl_sha256>, prf: Callable = <function hmac_openssl_sha256>, digestsize: int = 256, seed: Optional[bytes] = None, privkey: Optional[List[bytes]] = None, pubkey: Optional[List[bytes]] = None)[source]¶

Initialize WOTS object

Define under which circumstances a message should be signed or verified

Parameters:

w – The Winternitz parameter. A higher value reduces the space complexity, but increases the time complexity. It must be greater than 1 but less than :math: 2^{digestsize}. To get the best space to time complexity ratio, choose a value that is a power of two.
hashfunction – The hashfunction which will be used to derive signatures and public keys. Specify a function which takes bytes as an argument and returns bytes that represent the hash.
digestsize – The number of bits that will be emitted by the specified hash function.
privkey – The private key to be used for signing operations. Leave None if it should be generated. In this case it will be generated when it is required.
pubkey – The public key to be used for verifying signatures. Do not specify it if a private key was specified or if it should be derived. It will be derived when it is required.
seed – Seed which is used in the pseudo random function to generate bitmasks.
prf – Pseudo random function which is used to generate the bitmasks.

prf¶

Pseudo random function getter

Get the pseudo random function. It is used to generate the bitmasks.

Returns:	Reference to the pseudo random function

seed¶

Seed getter

Get the seed which is used in the pseudo random function to generate the bitmasks.

Returns:	Seed for pseudo random function

sign(message: bytes) → dict[source]¶

Sign a message

This function will create a valid signature for a message on success

Parameters: message – Encoded message to sign

Returns:

A dictionary containing the fingerprint of the message, which was created using the hash function that was specified during initialization of this object, the signature and a public key to verify the signature. Structure:

{
    "w":            winternitz parameter (Type: int),
    "fingerprint":  message hash (Type: bytes),
    "hashalgo":     hash algorithm (Type: str),
    "digestsize":   hash byte count (Type: int),
    "pubkey":       public key (Type: List[bytes]),
    "prf":          pseudo random function (Type: str),
    "seed":         Seed used in prf (Type: bytes),
    "signature":    signature (Type: List[bytes])
}

slots = ['__weakref__', '__seed', '__prf']¶

verify(message: bytes, signature: List[bytes]) → bool[source]¶

Verify a message

Verify whether a signature is valid for a message

Parameters:	message – Encoded message to verify signature – Signature that will be used to verify the message
Returns:	Whether the verification succeded

winternitz.signatures.hmac_openssl_sha256(message: bytes, key: bytes) → bytes[source]¶

Peudo random function for key and bitmask generation

This functions wraps a pseudo random function in a way that it takes a byte-sequence as an argument and returns a value which can be used for further generation of keys.

Parameters:	message – Byte-sequence to be hashed key – key to be used
Returns:	HMAC-sha256 hash

winternitz.signatures.openssl_sha256(message: bytes) → bytes[source]¶

Hash function for signature and public key generation

This functions wraps a hashfunction in a way that it takes a byte-sequence as an argument and returns the hash of that byte-sequence

Parameters:	message – Byte-sequence to be hashed
Returns:	Sha256 hash

winternitz.signatures.openssl_sha512(message: bytes) → bytes[source]¶

Hash function for signature and public key generation

This functions wraps a hashfunction in a way that it takes a byte-sequence as an argument and returns the hash of that byte-sequence

Parameters:	message – Byte-sequence to be hashed
Returns:	Sha512 hash

winternitz package¶

Submodules¶

winternitz.signatures module¶

Module contents¶