<p>Short answer: Yes it’s the same since there are 2048^24 mnemonic + passphrase combinations in both cases.</p>
<p>Slightly longer answer: Technically the second case is a bit better because the 12 words in the mnemonic have a checksum so they only contain 128 bits of entropy vs 132 bits in the 12 words in the passphrase. Any 12 words is a valid passphrase but any 12 words are not a valid mnemonic.</p>

CC BY-SA 4.0
2022-09-13T14:29:04.497Z
Yes you can put anything in the passphrase but my understanding of OPs question is he wants to use the same wordlist to pick 12 words for a passphrase
Mike D
CC BY-SA 4.0
2022-09-13T21:46:09.357Z
@RedGrittyBrick I explicitly asked for "another 12 word seed used as an additional passphrase". The question was about a comparison of the security of a 24 word seed without passphrase vs. a 12 word seed with another 12 word seed used as passphrase.
Wieland Gmeiner
CC BY-SA 4.0
2022-09-14T09:27:32.567Z
@wieland.gmeiner Thanks for the clarification. My comment was motivated to help authors clarify their contributions, I misunderstood your question so I'll edit it for you to make it clearer for anyone in future who has the same question and is searching for answers.
RedGrittyBrick
CC BY-SA 4.0
2022-09-13T01:45:46.540Z
2022-09-13T01:45:46.540Z
Mike D
<p>Does using a 12 word BIP39 mnemonic phrase in combination with another 12 word BIP39 mnemonic phrase used as an additional passphrase provide the same security as a 24 word mnemonic phrase without passphrase?</p>

<mnemonic-seed>
BIP39 security: 24 words vs. 12 words + 12 word passphrase
Wieland Gmeiner
# BIP39 security: 24 words vs. 12 words + 12 word passphrase

(Asked by: username_0 on 2022-09-12)

Does using a 12 word BIP39 mnemonic phrase in combination with another 12 word BIP39 mnemonic phrase used as an additional passphrase provide the same security as a 24 word mnemonic phrase without passphrase?

**Tags:** mnemonic-seed


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## 1 answers

### Answer by username_1 on 2022-09-13. Score: 1

Short answer: Yes it’s the same since there are 2048^24 mnemonic + passphrase combinations in both cases.

Slightly longer answer: Technically the second case is a bit better because the 12 words in the mnemonic have a checksum so they only contain 128 bits of entropy vs 132 bits in the 12 words in the passphrase. Any 12 words is a valid passphrase but any 12 words are not a valid mnemonic.

> **Comments:**
> **username_1**: Yes you can put anything in the passphrase but my understanding of OPs question is he wants to use the same wordlist to pick 12 words for a passphrase  
> **username_0**: @username_2 I explicitly asked for "another 12 word seed used as an additional passphrase". The question was about a comparison of the security of a 24 word seed without passphrase vs. a 12 word seed with another 12 word seed used as passphrase.  
> **username_2**: @wieland.gmeiner Thanks for the clarification. My comment was motivated to help authors clarify their contributions, I misunderstood your question so I'll edit it for you to make it clearer for anyone in future who has the same question and is searching for answers.  

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