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order: 3
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# AnthHandlers
## Handlers
The auth module presently has no transaction handlers of its own, but does expose
the special `AnteHandler`, used for performing basic validity checks on a transaction,
such that it could be thrown out of the mempool. Note that the ante handler is called on
`CheckTx`, but _also_ on `DeliverTx`, as Tendermint proposers presently have the ability
to include in their proposed block transactions which fail `CheckTx`.
### Ante Handler
```go
anteHandler(ak AccountKeeper, fck FeeCollectionKeeper, tx sdk.Tx)
if !tx.(StdTx)
fail with "not a StdTx"
if isCheckTx and tx.Fee < config.SubjectiveMinimumFee
fail with "insufficient fee for mempool inclusion"
if tx.ValidateBasic() != nil
fail with "tx failed ValidateBasic"
if tx.Fee > 0
account = GetAccount(tx.GetSigners()[0])
coins := acount.GetCoins()
if coins < tx.Fee
fail with "insufficient fee to pay for transaction"
account.SetCoins(coins - tx.Fee)
fck.AddCollectedFees(tx.Fee)
for index, signature in tx.GetSignatures()
account = GetAccount(tx.GetSigners()[index])
bytesToSign := StdSignBytes(chainID, acc.GetAccountNumber(),
acc.GetSequence(), tx.Fee, tx.Msgs, tx.Memo)
if !signature.Verify(bytesToSign)
fail with "invalid signature"
return
```
