Add info transactions (#5531)

* added text

* moved replay attack section

minor edits

* minor edit

* implemented Bill feedback

* link fix

docs/general/transaction-attacks.md

@@ -60,6 +60,26 @@ This will be showed in the Signer app and a careful user will notice it. If the
 Signer is already incorrect (or the Signer is corrupted) there is the risk of signing a non-intended
 transaction without the possibility of verifying it.
 
+### Replay Attack
+
+A replay attack is where past transactions can be replayed (same [balance](#balance-transfers),
+receiver account, etc.) without knowing private keys. It is an attack where publicly known data can
+be "replayed" as a new extrinsic. This could happen in the context of
+[reaping accounts](../learn/learn-accounts.md#existential-deposit-and-reaping) because the reaping
+process resets the nonce value. If all signed transactions until the nonce before the reaping event
+were immortal, all past transactions can be replayed once the account is refunded. There is no need
+for the attacker to know your private key, valid signatures for those past transactions and nonces
+already exist and are stored on-chain (meaning the private key was already used to generate those
+signatures).
+
+Making a [transaction mortal](../learn/learn-transactions.md#mortal-and-immortal-extrinsics) with a
+relatively short mortality window will almost certainly ensure that replay attacks are not possible,
+with the only exception being if the account is reaped and then re-funded shortly after submitting a
+mortal transaction, and then an attacker replays that transaction within the mortality window (i.e.,
+the specified block interval) and such transaction is valid (e.g. if you only have 10 DOT, and you
+try to issue an extrinsic sending 20 {{ polkadot: DOT :polkadot }}{{ kusama: KSM :kusama }}, the
+transfer will fail).
+
 ## Defense against Attacks
 
 :::warning

docs/learn/learn-transactions.md

@@ -77,23 +77,19 @@ Here are some key differences between the different types of extrinsics:
 
 ### Mortal and Immortal Extrinsics
 
-Extrinsics can be mortal (i.e. valid within a defined block interval) or immortal (i.e. always
-valid). By default and for security reasons, all extrinsics will be mortal, but always checking
-before signing is a good practice. This will avoid the chance of being a victim of a replay attack
-after [reaping an account](./learn-accounts.md#existential-deposit-and-reaping).
-
-A replay attack is where past transactions can be replayed (same [balance](#balance-transfers),
-receiver account, etc.) without knowing private keys. This could happen in the context of reaping
-accounts because the reaping process resets the nonce value. If all signed transactions until the
-nonce before the reaping event were immortal, all past transactions can be replayed once the account
-is refunded. There is no need for the attacker to know your private key, valid signatures for those
-past transactions and nonces already exist and are stored on-chain (meaning the private key was
-already used to generate those signatures).
-
-Making a transaction mortal will almost certainly ensure that replay attacks are not possible, with
-the only exception being if the account is reaped and then re-funded shortly after submitting a
-mortal transaction, and then an attacker replays that transaction within the mortality window (i.e.,
-the specified block interval).
+Transactions are generally irreversible once confirmed and added to the blockchain, an immutable
+ledger of all transactions. This means users must exercise caution, as mistakes such as sending
+{{ polkadot: DOT :polkadot }}{{ kusama: KSM :kusama }} to the wrong address cannot be reverted. The
+permanence of transactions highlights the importance of careful verification before signing any
+transaction on a blockchain network. It is usually a
+[good practice not to blind sign transactions](../general/transaction-attacks.md) to avoid being
+victim of an attack.
+
+In blockchain terms, transactions can be **mortal** extrinsics (i.e. valid within a defined block
+interval, usually short), or **immortal** extrinsics (i.e. always valid). It is possible to make
+immortal transactions on {{ polkadot: Polkadot. :polkadot }}{{ kusama: Kusama. :kusama }} However,
+[for security reasons](../general/transaction-attacks.md#replay-attack), it is highly recommended
+not to do so and most wallet software will not allow you to make an immortal extrinsic.
 
 ### Balance Transfers