NAME

nano - Tcl bindings for Nano

SYNOPSIS

nano::
address::
toPublicKey address ?-hex|-binary? ?-verify|-no-verify?

fromPublicKey pubKey ?-xrb|-nano?

fromPrivateKey privateKey ?-xrb|-nano?

key::
newSeed ?-hex|-binary?

newKey ?-hex|-binary?

fromSeed seed ?index? ?-hex|-binary?

publicKeyFromPrivateKey privateKey ?-hex|-binary?

block::
json::toBlock blockJSON

json::fromDict blockDict

json::fromBlock blockData ?-xrb|-nano? ? -type=blockType ? ? -signKey=privateKey ?

json::sign blockJSON privateKey ?-update|-signature ?-hex|binary??

json::verifySignature blockJSON

json::work blockJSON ?-update|-work ?-hex|-binary??

json::validateWork blockJSON

json::filter blockJSON

dict::toBlock blockDict

dict::fromJSON blockJSON

dict::fromBlock blockData ?-xrb|-nano? ? -type=blockType ? ? -signKey=privateKey ?

dict::sign blockDict privateKey ?-update|-signature ?-hex|binary??

dict::verifySignature blockDict

dict::work blockDict ?-update|-work ?-hex|-binary??

dict::validateWork blockDict

hash blockData ?-hex|-binary?

signBlockHash blockHash privateKey ?-hex|-binary?

sign blockData privateKey ?-hex|-binary?

verifyBlockHash blockHash signature publicKey

verify blockData signature publicKey

create::send args

create::receive args

create::setRepresentative args

work::
fromWorkData blockHashOrPublicKey ?-hex|-binary?

fromBlock blockData

validate workData work

account::
setFrontier account frontierHash balance representative

getFrontier account

getFrontier account ?frontierHash|balance|representative?

addPending account blockHash amount

getPending account ?blockHash?

clearPending account ?blockHash?

receive account blockHash privateKey

receiveAllPending account privateKey

send fromAccount toAccount amount privateKey

setRepresentative account representative privateKey

INTRODUCTION

Nano is a low-latency payment platform that requires minimal resources, relying on a peer-to-peer network to distribute "blocks", which are cryptographically signed transactions. This package provides bindings for interacting with the Nano network from Tcl. Nano uses Ed25519 with Blake2b as the cryptographic hashing primitive for digital signatures, rather than the common construction of Ed25519 with the SHA2-512 cryptographic hashing function. Nano implements a "blockchain", which is a cryptographic linked-list, by identifying every "block" by its cryptographic hash and providing a pointer from every block to its predecessor in the "chain" as part of the hashed data. This predecessors is referred to here as the "previous" block. In Nano, each account has its own blockchain and they reference each other using a data structure referred to as "block lattice", where the individual chains contain blocks that reference blocks in other chains to tie them together. The field within blocks that reference other blocks on a different blockchain is referred to as either the "link" field or "source block hash". Each Nano block also encapsulates the full state of the account, containing, at a minimum, a tuple of (account, balance, representative, previous). Since Nano blocks are signed by independent actors, who may, for their own gain, generate multiple valid blocks referring to the same predecessor (previous) block, an arbitration mechanism is employed by the Nano network to decide which blocks are valid within a given chain. This arbitration mechanism operates on the principles of consensus. Each account holder has a stake in the network operating nominally, otherwise the balance represented by an account is not useful for a transfer of value. In Nano the stake an account has in the network is equal to the account's balance. The larger the stake an account has the more incentivized the account-holder is to ensure the network is operating nominally and not accepting multiple blocks that reference the same predecessor. Nano utilizes a mechanism called voting to determine which blocks are valid and which blocks are not valid. Each stakeholder votes their stake upon seeing a new subordinate block (i.e., a block with a unique previous value). Since voting is an active and on-going process that occurs on the Nano peer-to-peer network, participants must be online to vote their stake. As this is often inconvenient or impossible, stakeholders may select another stakeholder to vote their share of the network. This delegate is referred to as a representative. Representatives should be chosen carefully by stakeholders since malicious representatives may attempt to gather voting power and destabilize the Nano network by altering decisions made by consensus previously. Nano accounts are referred to by address. A Nano address starts with the prefix "nano_" or "xrb_". A Nano address is actually the public portion of a private/public keypair, plus the prefix, and a checksum to ensure that no digits are mistyped by users when communicating them. Nano public keys are 256-bit keys in the Ed25519 algorithm. A user may have many accounts. To simplify the process of maintaining the private/public keypairs for all the accounts, Nano supports the concept of a wallet. A wallet is a conceptual entity that is used to refer to a seed, which is a random 256-bit number that can be used to derive multiple private/public keypairs from. Balances in Nano are stored in a 128-bit integer value. There are various units for representing the balance, the smallest and base unit is called "raw". The most common unit for users to use is called "Nano", one of which is equal to 1e30 raw.

Addresses

Nano addresses are composed of a prefix (either "nano_" or "xrb_") and 300 bits of base32 encoded data. The 300-bits of base32 encoded data produce a string that is 60 characters long using the base32 alphabet 13456789abcdefghijkmnopqrstuwxyz. The format of these 300 bits are

   struct {
       uint4_t padding = 0000b;
       uint256_t publicKey;
       uint40_t  checksum;
   }

The checksum is computed as a 5 byte (40 bit) Blake2b hash of the 256-bit public key (in binary format), followed by reversing the bytes. For example the public key DC1512154EB72112B8CC230D7B8C7DD467DA78E4763182D6CAFAADB14855A5E8 which has a 5-byte Blake2b hash of {0x18, 0x74, 0xA3, 0x46, 0x9C} would be encoded as 0000.DC1512154EB72112B8CC230D7B8C7DD467DA78E4763182D6CAFAADB14855A5E8.9C46A37418 which when encoded in base32 and the prefix added produces the address nano_3q1o4acnxfs34cwerarfhg89uo59ubwgaxjjiddeoyofp767dbhamj5c8x1r.

Network

The Nano network consists of two different peer-to-peer networks. One for real-time block updates over UDP, and another for bulk ledger updates over TCP (bootstrapping). The real-time network is a broadcast style network where every message sent over it are relayed to all other nodes. The customary and default port for the real-time/UDP network is 7075/udp, while the default port for the bootstrapping/TCP network is 7075/tcp. The format of the messages on both networks is the same, however not every type of message may be used on either network. The keepalive message type is invalid on the TCP (bootstrapping) network and the bulk_pull message type is invalid on the UDP (real-time) network. The format of message are an 8 byte header consisting of:

   struct {
       uint8_t magicProtocol = 0x52;
       uint8_t magicNetwork  = 0x41/0x42/0x43;
       uint8_t versionMax;
       uint8_t version;
       uint8_t versionMin;
       uint8_t messageType;
       uint16_t extensions;
   };

Where the magicProtocol field must be the value 0x52 (which is ASCII 'R') and the magicNetwork field must be one of 0x41, 0x42, or 0x43 corresponding to one of the three Nano networks. A value of 0x41 (ASCII 'A') represents the Test network; A value of 0x42 (ASCII 'B') represents the Beta network; A value of 0x43 (ASCII 'C') represents the Main network. The various version fields control the relaying of the message to nodes running various versions of the Nano network protocol (distinct from the Nano reference implementation version). The versionMax and versionMin fields indicate the inclusive range of acceptable versions to relay or broadcast this message to. The version field indicates what version of the Nano protocol this node is using. The messageType field indicates what type of message is being relayed, and must conform to the following enumeration

messageType	Name	On Bootstrap	On Realtime	Version
0x00	Invalid	Yes	Yes	1+
0x01	Not_A_Type	Yes	Yes	1+
0x02	Keepalive	No	Yes	1+
0x03	Publish	No	Yes	1+
0x04	Confirm_Req	No	Yes	1+
0x05	Confirm_Ack	No	Yes	1+
0x06	Bulk_Pull	Yes	No	1+
0x07	Bulk_Push	Yes	No	1+
0x08	Frontier_Req	Yes	No	1+
0x09	Bulk_Pull_Blocks	Yes	No	Deprecated
0x0A	Node_ID_Handshake	Yes	No	12+
0x0B	Bulk_Pull_Account	Yes	No	12+

Extensions

The following message types have extension bits used as flags: Node_ID_Handshake, Bulk_Pull.

The following message types encode a block type in the extension bits: Publish, Confirm_Req, and Confirm_Ack. The block type is encoded in the lower 4 bits of the first byte of the extensions field (i.e., (extensions & 0x0f00 >> 8)).

Payload

Following the message header comes the payload for the particular message type.

Invalid

TODOC

Not_A_Type

TODOC

Keepalive

The Keepalive message serves as an introduction and beaconing mechanism for the Nano real-time network. The Keepalive message requires exactly 8 IPv6 address and port number tuples to be sent as its payload. The IPv6 addresses are each 128-bits (16-bytes) long and the port numbers are 16-bit integers sent in little endian byte order. The payload for the Keepalive message type is 144 bytes in size.

Publish

The Publish message serves as a mechanism to introduce new blocks into the Nano real-time network. The block type is encoded in the Extensions field as described above. The payload is the contents of the block.

Confirm_Req

The Confirm_Req message requests that all online representatives "vote" on a block. The block type is encoded in the Extensions field as described above. The payload is the contents of the block to be voted on.

Confirm_Ack

The Confirm_Ack message is sent in response to either a new block being observed by a representative or in response to an explicit Confirm_Req. The block type is encoded in the Extensions field as described above. If the block type is specified as Not_A_Block then the payload is a sequence of hashes. Due to IPv4 fragment size limits this typically does not exceed 12 hashes. If the block type is something other than Not_A_Block then the payload is the contents of the block that is being voted on.

Bulk_Pull

The Bulk_Pull message is used to pull the entire chain for an account, down to its beginning or to a given block. It takes 2 arguments, both of them 256-bit. The first argument is the account, so its 256-bit public key should be encoded as binary in big-endian notation. The second argument is the block hash to stop sending at, or 256 bits of 0s to indicate that the entire chain should be sent. The payload for Bulk_Pull messages is 64 bytes in size.

The response from a Bulk_Pull request will be a stream of tuples, each containing a 8-bit block type identifier, and a block message. When no more blocks are available the response is terminated by sending the block type identifier for not_a_block and no block message follows.

Bulk_Push

TODOC

Frontier_Req

The Frontier_Req message is used to pull a list of accounts from a remote node for the purpose of bootstrapping. It requires 3 arguments: The 256-bit public key of an account to start with, a 32-bit integer denoting the age of accounts to return, and a 32-bit integer denoting the number of records to return. If the age parameter is 0xffffffff then all records are returned, regardless of age. If the count parameter is 0xffffffff then all records are returned and no limit is imposed.

The response from a Frontier_Req is a 256-bit public key, and the 256-bit block hash that corresponds to the frontier (most recent block) for that account's blockchain from the node where the response was generated.

Bulk_Pull_Blocks

TODOC

Node_ID_Handshake

TODOC

Bulk_Pull_Account

TODOC

PROCEDURES

Addresses

::nano::address::toPublicKey

address ?-hex|-binary? ?-verify|-no-verify? -> publicKey

Converts a Nano address to a public key. The -hex option indicates that the public key should be returned in hexadecimal form. The -binary option indicates that the public key should be returned in binary form. The -verify option verifies the checksum embedded in the Nano address before returning. The -no-verify option inhibits verifying the checksum embedded in the Nano address.

::nano::address::fromPublicKey

pubKey ?-xrb|-nano? -> address

Converts a public key to a Nano address. The -xrb option specifies that the returned address should be prefixed with the old-style "xrb_" prefix, where the -nano option specifies that the returned address should be prefixed with the new-style "nano_" prefix.

::nano::address::fromPrivateKey

privateKey ?-xrb|-nano? -> address

Converts a private key to a Nano address. It accepts the same arguments as fromPublicKey.

Key Management

::nano::key::newSeed

?-hex|-binary? -> seed

Generates a new seed. A seed is a 256-bit bit-field which, along with a 32-bit index, is used to derive enumerated keys from a single point of entropy. See the fromSeed procedure. The -hex and -binary options determine the formatting of the result.

::nano::key::newKey

?-hex|-binary? -> privateKey

Generates a new private key. A private key can be used to sign transactions, which can then be verified with its corresponding public key (see publicKeyFromPrivateKey). This procedure is normally not used, but rather private keys are derived from a seed and index pair using the fromSeed procedure. The -hex and -binary options determine the formatting of the result.

::nano::key::fromSeed

seed ?index? ?-hex|-binary? -> privateKey

Derive a private key from the seed specified as seed and the index indicated. This procedure is deterministic (i.e., the same seed and index will always give you the same private key). This procedure is used to derive many keypairs from a single user-managed piece of data, so the user does not have to manage multiple private keys. If the index is not specified it defaults to 0. The -hex and -binary options determine the formatting of the result.

::nano::key::publicKeyFromPrivateKey

privateKey ?-hex|-binary? -> publicKey

Converts a private key into its corresponding public key. Normally Ed25519 private keys are a concatenation of the private and public keys, however in this package they are each treated separately. The -hex and -binary options determine the formatting of the result.

Low-level Block

::nano::block::representation::toBlock

blockRepresentation -> blockData

Converts from one of the internal representations (either Tcl dictionary or JSON) to a Nano block. The representation portion of the command name may be one of dict or json.

::nano::block::json::fromDict

blockDict -> blockJSON

Converts from a Tcl dictionary representation to a JSON representation of a block.

::nano::block::json::filter

blockJSON -> blockJSON

Filters out JSON object attributes which are not suitable for using with other implementations, such as _comment, _workData, and _blockHash.

::nano::block::dict::fromJSON

blockJSON -> blockDict

Converts from a JSON object representation to a Tcl dictionary representation of a block.

::nano::block::representation::fromBlock

blockData ?-xrb|-nano? ? -type=blockType ? ? -signKey=privateKey ? -> blockRepresentation

Parses a Nano block and returns either a Tcl dictionary or a JSON object. The -xrb option causes all parsed addresses to be prefixed with the old-style "xrb_" address prefix, while the -nano option causes them to be prefixed with the new-style "nano_prefix". The representation portion of the command name may be one of dict or json.

::nano::block::representation::sign

blockRepresentation privateKey ?-update|-signature ?-hex|binary?? -> signature|blockJSON

Sign a block, in either Tcl dictionary or JSON representation, with the specified privateKey. If the -update option is used, return the object with the updated attribute. If the -signature option is used, return just the signature. The -hex and -binary options determine the formatting of the result. The representation portion of the command name may be one of dict or json.

::nano::block::representation::verifySignature

blockRepresentation -> boolean

Verify the signature on a block, in either Tcl dictionary or JSON representation, matches the public key specified in the account attribute of that object. This may not work correctly for old-style blocks unless you manually add the account attribute. The representation portion of the command name may be one of dict or json.

::nano::block::representation::work

blockRepresentation ?-update|-work ?-hex|binary?? -> work|blockRepresentation

Generate proof-of-work (PoW) required to submit a given block to the network. Nano uses PoW to increase the cost of submitting blocks to the network to cut down on spam. The work that is computed is based on the hash of the previous block on this chain, or if there is no previous block on this chain (i.e., because it is the first block on an account) the public key of the account. If the -update option is used, return the object with the updated attribute. If the -work option is used, just return the work. The -hex and -binary options determine the formatting of the result. The representation portion of the command name may be one of dict or json.

::nano::block::representation::validateWork

blockRepresentation -> boolean

Validate the proof-of-work (PoW) in the object specified as blockRepresentation with the attribute work is valid for the block passed in. The representation portion of the command name may be one of dict or json.

::nano::block::signBlockHash

blockHash privateKey ?-hex|-binary? -> signature

Compute an Ed25519-with-Blake2b signature of a given block hash specified as blockHash with the private key specified as privateKey. In Nano, signed blocks are signed by signing the block's hash thus all that is needed to sign a block is its hash and the private key that corresponds to the account. NOTE: Ensure that the privateKey specified matches the account the block belongs to. The -hex and -binary options determine the formatting of the result.

::nano::block::verifyBlockHash

blockHash signature publicKey -> boolean

Verify that a block hash (blockHash) was signed (signature) by an account holding the private key that corresponds to the public key specified as publicKey.

::nano::block::create::send

from address to address previous blockHash representative address previousBalance integer amount integer ? -json boolean ? -> blockJSON|blockDict

This is a low-level interface for creating blocks which correspond to sending Nano from one account to another. It constructs a block which sends the amount specified from the from address to the destination (to). The previous block's hash must be specified as the blockHash following previous. Additionally the balance of the account at the previous block must be supplied as the integer argument to previousBalance. All balance amounts are in units of raw. If the optional -json argument is used and specified as true the result is a JSON representation, otherwise a Tcl dict representation is used.

::nano::block::create::receive

to address sourceBlock blockHash previous blockHash representative address previousBalance integer amount integer ? -json boolean ? -> blockJSON|blockDict

This is a low-level interface for creating blocks which correspond to receiving (pocketing) Nano previously sent from another account to the account specified as the address supplied to the to argument. It constructs a block which receives the amount of Nano specified as the amount argument. The block hash (blockHash) of the send block which was used to send the Nano to this account must be specified as the argument to the sourceBlock option. The previous block's hash must be specified as the blockHash following previous. Additionally the balance of the account at the previous block must be supplied as the integer argument to previousBalance. All balance amounts are in units of raw. If the optional -json argument is used and specified as true the result is a JSON representation, otherwise a Tcl dict representation is used.

::nano::block::create::setRepresentative

account address previous blockHash representative address ? -json boolean ? -> blockJSON|blockDict

This is a low-level interface for creating blocks which correspond to an explicit change of representative. Representatives in Nano are used as part of the Delegated Proof-of-Stake (dPoS) consensus mechanism which is used by the Nano network to determine which block (if any) out of many possible subordinate blocks in a chain are valid. So that every account holder does not have to be online to vote for valid transactions, an account may delegate another account to vote its stake on its behalf. That delegate is called a representative. An account may change its representative at any time by issuing a block with a new representative, such as a send or receive block, or by issuing an explicit change of representative block. This procedure creates an explicit change of representative block for the account specified. It changes to the delegate to the representative specified. Further, the blockHash of the previous block must be specified as the argument to previous. If the optional -json argument is used and specified as true the result is a JSON representation, otherwise a Tcl dict representation is used.

Work Generation

::nano::work::fromWorkData

blockHashOrPublicKey ?-hex|-binary? -> work

Create proof-of-work (PoW) from a block hash or public key. Which one is used depends on whether or not there are any other blocks in this account's chain. If this is the first block in this account's chain then the public key of the account is used, otherwise the hash of the blocks predecessor (previous) is used. The specific value needed should be accessible from the _workData member of a JSON object or Tcl dictionary. Note that this attribute (and all attributes that begin with an underscore) should be discarded when sending the block outside of the Tcl process. The -hex and -binary options determine the formatting of the result.

::nano::work::fromBlock

blockData -> work

This is a convenience procedure which computes work data (either a block hash or a public key) for a given block and then calls fromWorkData.

::nano::work::validate

workData work -> boolean

This procedure validates that the supplied work is valid for the supplied workData, which is either a block hash or an account public key. For more information see the description of fromWorkData.

High-level Account

:nano::account::setFrontier

account frontierHash balance representative

This procedure is used as part of the High-level Account interface. It sets the frontier, which is the block hash (frontierHash) and data (balance, representative) associated with that block that corresponds to the head of an account's chain.

:nano::account::getFrontier

account -> frontierInfo

This procedure is used as part of the High-level Account interface. It gets the Tcl dictionary associated with the frontier most recently set for the specified account.

:nano::account::getFrontier

account ?frontierHash|balance|representative? -> frontierHash|balance|representative

This procedure is used as part of the High-level Account interface. It gets a specific item from Tcl dictionary associated with the frontier most recently set for the specified account.

:nano::account::addPending

account blockHash amount

This procedure is used as part of the High-level Account interface. It is used to indicate than a given account has a receive block that they could create. The block hash of the corresponding send block should be supplied as the blockHash parameter. The amount of Nano that was sent in the send block should be specified as the amount parameter (in units of raw).

:nano::account::getPending

account ?blockHash? -> dict

This procedure is used as part of the High-level Account interface. It is used to retrieve information stored by addPending for a given account. If the blockHash parameter is supplied then a Tcl dictionary is returned with a key called amount which contains the amount stored previously. If the blockHash parameter is not supplied then a Tcl dictionary is returned with keys corresponding to each block hash pending for the specified account, and containing a subordinate Tcl dictionary with a key called amount as previously described.

::nano::account::clearPending

account ?blockHash?

This procedure is used as part of the High-level Account interface. It is used to clear (that is, remove from the conceptual state of "pending") entries created previously with addPending for a given account. If the blockHash parameter is supplied then only the entry corresponding to that blockhash is cleared, otherwise all entries for the specified account are cleared.

:nano::account::receive

account blockHash privateKey -> blockJSON|blockDict

This procedure is used as part of the High-level Account interface. It is used to generate a receive block. Its interface is subject to change and not considered stable.

:nano::account::receiveAllPending

account privateKey -> listOfBlockJSON|listOfBlockDict

This procedure is used as part of the High-level Account interface. It is used to generate receive blocks for every pending receive on a given account. Its interface is subject to change and not considered stable.

:nano::account::send

fromAccount toAccount amount privateKey -> blockJSON|blockDict

This procedure is used as part of the High-level Account interface. It is used to generate a send block. Its interface is subject to change and not considered stable.

::nano::account::setRepresentative

account representative privateKey -> blockJSON|blockDict

This procedure is used as part of the High-level Account interface. It is used to generate a block that changes the representative for the given account. Its interface is subject to change and not considered stable.

EXAMPLES

Example 1: Generate a new seed and derive 10 addresses from it

package require nano 1.1

set seed [::nano::key::newSeed -hex]
puts "Generated seed: $seed"

for {set index 0} {$index < 10} {incr index} {
	set accountPrivateKey [::nano::key::fromSeed $seed $index -hex]
	set accountAddress [::nano::address::fromPrivateKey $accountPrivateKey]
	puts "    - $index: $accountAddress"
}

AUTHOR

Roy Keene <rkeene@nano.org>