<p>From BIP39:"A user may decide to protect their mnemonic with a passphrase. If a passphrase is not present, an empty string "" is used instead."</p>

<p>The passphrase can be added in the transformation from the mnemonic phrase to the seed. It is not added IN the mnemonic but in an other point of the procedure.</p>

<p>A consequence of this is that:
"The described method also provides plausible deniability, because every passphrase generates a valid seed (and thus a deterministic wallet) but only the correct one will make the desired wallet available."</p>

<p>The passphrase is a second parameter in the "generate the seed from the mnemonic" procedure. If you don't provide it the procedure assumes that the second parameter is "".</p>

CC BY-SA 3.0
2018-03-09T15:31:18.557Z
2018-03-09T15:31:18.557Z
Gabriele Domenichini
<p>It's misleading to call it the "25th word". It is a "passphrase" and one should select a strong passphrase in order to get good security.</p>

CC BY-SA 3.0
2018-03-09T01:16:39.887Z
2018-03-09T01:16:39.887Z
Tailer
<p>By default ledger nano s generates a 24 word mnemonic. What is the 25th word feature? Is the the passphrase they are talking about?</p>

<seed><hardware-wallet><ledger-hardware-wallet>
What is the 25th word in a mnemonic seed when used on a ledger nano s?
Patoshi パトシ
# What is the 25th word in a mnemonic seed when used on a ledger nano s?

(Asked by: username_0 on 2018-03-08)

By default ledger nano s generates a 24 word mnemonic. What is the 25th word feature? Is the the passphrase they are talking about?

**Tags:** seed, hardware-wallet, ledger-hardware-wallet


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## 2 answers

### Answer by username_1 on 2018-03-09. Score: 3 | Accepted answer

From BIP39:"A user may decide to protect their mnemonic with a passphrase. If a passphrase is not present, an empty string "" is used instead."

The passphrase can be added in the transformation from the mnemonic phrase to the seed. It is not added IN the mnemonic but in an other point of the procedure.

A consequence of this is that:
"The described method also provides plausible deniability, because every passphrase generates a valid seed (and thus a deterministic wallet) but only the correct one will make the desired wallet available."

The passphrase is a second parameter in the "generate the seed from the mnemonic" procedure. If you don't provide it the procedure assumes that the second parameter is "".


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### Answer by username_2 on 2018-03-09. Score: 1

It's misleading to call it the "25th word". It is a "passphrase" and one should select a strong passphrase in order to get good security.


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