Box Focused Guard Script Framework

Guard scripts determines whether a box is spendable in a transaction. This design focuses on the component within a box and allow the components written down to guide the ErgoScript implementation of the Guard Script.

List out
1. Value
2. Tokens
3. Registers
4. Actions

Framework + Example

Value: 0.1 Ergs

Token List:

Sample NFT Name
1. Identification NFT - 1

Registers:

R4 → Personal Details

DataType - Coll[Coll[Byte]]
Data List
1. First Name
2. Last Name
3. Address

R5 → Age, HOB and Grades

DataType - Coll[Long]
Data List
1. Age
2. HOB (Height of Birth)
3. Math Score

R6 → Joined DeCo

DataType - Boolean
1. Took DeCo Layman Course

R7 → Records

Last Recorded Height

Actions List:

Grows Older Every Year
INPUTS Position: 0
Trigger Condition:
1. When all other conditions fail (an else condition)
Contract Conditions:
1. Condition 1: Everything stays the same other than the age
2. Condition 2: Can only increment by n, where n = ((Current Height - HOB)/(Height in a year)) - Age
3. Condition 3: Self reproducing box in OUTPUTS(0)
Math Score changed after tests
INPUTS Position: 0
Trigger Condition:
1. Test Score Identification Token in INPUTS (1)
Contract Conditions:
1. Condition 1: Everything stays the same other than the Math Score
2. Condition 2: Math score is from Test Score Box R4[Long]
3. Condition 3: Self reproducing box in OUTPUTS(0)
Decided to take DeCo Layman Course
INPUTS Position: 0
Trigger Condition:
1. If DeCo award NFT is in INPUTS(1)
Contract Conditions:
1. Condition 1: Math Score >= 98
2. Condition 3: Self reproducing box in OUTPUTS(0)

Box Conditions:

Persisted data

Identification Token
Personal details

Other Conditions:

Records updated for every Tx

Building the ErgoScript

After forming the framework. Take the actions and refer to its components to design the ErgoScript for the Guard Script.

Fill the Box Conditions

{
    val persistIdentificationToken = allOf(Coll(
        // ._1 == Id, ._2 == quantity
        SELF._tokens(0)._1 == OUTPUTS(0)._tokens(0)._1,
        SELF._tokens(0)._2 == OUTPUTS(0)._tokens(0)._2
    ))

    val persistPersonalDetails =
        SELF.R4[Coll[Coll[Byte]] == OUTPUTS(0).R4[Coll[Coll[Byte]]

    val recordsUpdated =
        OUTPUTS(0).R7 == HEIGHT

    val boxConditionsCheck = allOf(Coll(
        persistIdentificationToken,
        persistPersonalDetails,
        recordsUpdated))

    val ageNHOBCheck = allOf(Coll(
        SELF.R5[Coll[Long]].get(0) == OUTPUTS(0).R5[Coll[Long]].get(0),
        SELF.R5[Coll[Long]].get(1) == OUTPUTS(0).R5[Coll[Long]].get(1)
    ))

    val mathScoreCheck =
        SELF.R5[Coll[Long]].get(2) == OUTPUTS(0).R5[Coll[Long]].get(2)

    val deCoAwardCheck =
        SELF.R6[Boolean].get == OUTPUTS(0).R5[Boolean].get

    if (INPUTS(1)._tokens(0)._1 == deCoNFTAwardToken) {
        sigmaProp(allOf(Coll(
            boxConditionsCheck,
            ageNHOBCheck,
            SELF.R5[Coll[Long]].get(2) >= 98
        )))
    } else if (INPUTS(1)._tokens(0)._1 ==  testScoreIdentification) {
        sigmaProp(allOf(Coll(
            boxConditionCheck,
            ageNHOBCheck,
            OUTPUTS(0).R5[Coll[Long]].get(2) == INPUTS(1).R4[Long].get
        ))
    } else {
        val maxAge = (HEIGHT - SELF.R5[Coll[Long]].get(1))/(heightInAYear)
        val ageNotExceedMaxAge = OUTPUTS(0).R5[Coll[Long]].get(0) <= maxAge

        sigmaProp(allOf(Coll(
            boxConditionsCheck,
            deCoAwardCheck,
            mathScoreCheck,
            ageNotExceedMaxAge
        ))
    }
}

Blank Guard Script Framework

Value: {insert} Ergs

Token List:

Sample NFT Name
1. Identification NFT - 1

Registers:

R4 →

DataType -
Data List

R5 →

DataType -
Data List

R6 →

DataType -

R7 →

DataType -

Actions List:

{Action}
INPUTS Position:
OUTPUTS Position:
Trigger Condition:
Contract Conditions:
1. Condition 1:
{Action}
INPUTS Position:
OUTPUTS Position:
Trigger Condition:
Contract Conditions:
1. Condition 1:
{Action}
INPUTS Position:
OUTPUTS Position:
Trigger Condition:
Contract Conditions:
1. Condition 1:

Box Conditions:

Persisted data

Other Conditions

PinLock Contract Guard Script Framework

Value: X (Depends on what the user put in) Ergs

Registers:

R4 → Pin of the box (Hashed)

DataType - Coll[Byte]

R5 → TimeFrame for Pin to be changed (If block height is Larger than this height, then pin cannot be changed)

DataType - Long

Actions List:

Box can be spent only if the Output box pin is the same as the current box
INPUTS Position: 0
Trigger Conditions:
1. Proposition Byte is not the same → Pin Lock is being spent to become a user box
  1. Therefore, the propositionBytes is not the same
Contract Conditions:
1. Condition 1: R4 of self (Hashed Pin) == Hashed R4 of OUTPUTS(0)
Pin of the box can be changed within a certain height (timeframe)
INPUTS Position: 0
Triggering Condition:
Anything else other than 1
Contract Conditions:
1. Condition 1: Block Height cannot be larger than R5’s Height
  1. Code: HEIGHT < SELF.R5[Long].get
2. Condition 2: Pin has to be different
  1. Comparing against OUTPUTS(0) → Newly Generated PinLock Box
  2. Code: SELF.R4[Coll[Byte]].get ≠ OUTPUTS(0).R4[Coll[Byte]].get

Box Conditions:

Persisted data

Pin Change Expiry Height cannot be changed

Comparing against OUTPUTS(0) → Newly Generated PinLock Box
Code: SELF.R5[Long].get == OUTPUTS(0).R5[Long].get

{

        // Triggering condition for Scenario 1
        val isPinLockBoxRedeemed = SELF.propositionBytes != OUTPUTS(0).propositionBytes

        if (isPinLockBoxRedeemed) {
            // Redeem PinLock Box
            val isPinCorrect = SELF.R4[Coll[Byte]].get == black2b256(OUTPUTS(0).R4[Coll[Byte]].get)
            sigmaProp(isPinCorrect)
        } else {
            // Change Pin
            val isExpiryHeightSame = SELF.R5[Long].get == OUTPUTS(0).R5[Long].get
            val isExpiryTimePassed = HEIGHT < SELF.R5[Long.get
            val isPinDifferent = SELF.R4[Coll[Byte]].get != OUTPUTS(0).R4[Coll[Byte]].get

            sigmaProp(allOf(Coll(
                isExpiryHeightSame,
                isExpiryTimePassed,
                isPinDifferent)))
        }
}

Box Focused Guard Script Framework

Framework + Example​

Building the ErgoScript​

Blank Guard Script Framework​

PinLock Contract Guard Script Framework​

Framework + Example

Building the ErgoScript

Blank Guard Script Framework

PinLock Contract Guard Script Framework