# What is the 122 cbor tag

**URL:** <https://forum.cardano.org/t/what-is-the-122-cbor-tag/142502>\
**Category:** Transaction Metadata\
**Created:** [27 January 2025 15:07 UTC](https://forum.cardano.org/t/what-is-the-122-cbor-tag/142502 "2025-01-27T15:07:45Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![zing-rsa](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.cardano.org/zing-rsa/32/82727_2.png) [@zing-rsa](https://forum.cardano.org/u/zing-rsa)\
**Post date:** [27 January 2025 15:07 UTC](https://forum.cardano.org/t/what-is-the-122-cbor-tag/142502/1 "2025-01-27T15:07:45Z")

</div>

I see that in the `jpg.store` datum attached to offers there is a 122 cbor tag. The following is a snippet from the datum used in a collection offer:

```auto
121([_
    122([_
        h'84CC25EA4C29951D40B443B95BBC5676BC425470F96376D1984AF9AB'
    ]),
    121([_
        121([_
            122([_
                h'2C967F4BD28944B06462E13C5E3F5D5FA6E03F8567569438CD833E6D'
            ])
        ])
    ])
])

```

I noticed that [Lucid](https://github.com/spacebudz/lucid) fails to parse this datum using the following `Data` schema:

```typescript
Data.Object({
    paymentCredential: Data.Object({ 
        pubKeyHash: Data.Bytes() 
    }),
    stakeCredential: Data.Object({
        container: Data.Object({ 
            container: Data.Object({
                stakeKeyHash: Data.Bytes()
            })
        }) 
    }),
})

```

However manually replacing the hex in the cbor to change the 122 tags for 121 tags fixes that issue, with the same Lucid schema. Is 122 not an object? Is there somewhere I can read up on these tags? thanks 🙂

---

<div class="post-metadata">

**Author:** ![zing-rsa](https://sea1.discourse-cdn.com/flex023/user_avatar/forum.cardano.org/zing-rsa/32/82727_2.png) [@zing-rsa](https://forum.cardano.org/u/zing-rsa)\
**Post date:** [7 February 2025 06:46 UTC](https://forum.cardano.org/t/what-is-the-122-cbor-tag/142502/2 "2025-02-07T06:46:35Z")

</div>

I’ll answer since I managed to figure this out. Seems a bit obvious in retrospect but none the less:  
Starting with the `121` tag, it encodes the first constructor of a type, ie. `Constr 0`. Following on from that, the `122` tag encodes the second, ie. `Constr 1`, and so on.

Using some haskell type examples:

```auto
data Bool
  = False -- Constr 0 []
  | True -- Constr 1 []

data MyOption
  = Some Int -- Constr 0 [...]
  | None -- Constr 1 []

data MyEither
  = Left Int -- Constr 0 [...]
  | Right String -- Constr 1 [...]

data Color
  = Red -- Constr 0 []
  | Green -- Constr 1 []
  | Blue -- Constr 2 []

```

Therefore the example in my initial question is a case of having some “Eithers” and we can use Lucid’s `Data.Enum()` to successfully decode them like so:

```ts
const PubKeyCredential = { PubKeyCredential: { pubkeyhash: Data.Bytes()}};
const ScriptCredential = { ScriptCredential: { scripthash: Data.Bytes()}};

const Credential = Data.Enum(
    PubKeyCredential,
    ScriptCredential
)

const StakeCredential = Data.Nullable(Data.Object({ credential: Credential }))

const JpgDatumAddress = 
    Data.Object({
        paymentCredential: Credential,
        stakeCredential: StakeCredential
    })

```