<p>It appears many unused opcodes were disabled in 2010 for security reasons (at least OP_CAT) or as a security precaution (many others).</p>
<p><a href="https://bitcoin.stackexchange.com/users/24925/pseudonymous">Pseudonymous</a> commented that the first BIPs didn't start until 2011 - a year later.</p>

CC BY-SA 4.0
2020-12-29T16:15:13.910Z
2020-12-29T16:15:13.910Z
RedGrittyBrick
<p>On <a href="https://en.bitcoin.it/wiki/Script" rel="nofollow noreferrer">Bitcoin wiki</a> several opcodes are listed as &quot;disabled&quot;.</p>
<p>My question is simple: which Bitcoin improvement proposal proposed to disable them, and when they have effectively been disabled in the past?</p>
<p>I'm particularly interested in the OP_MOD arithmetic opcode.</p>
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<script><bip><opcodes>
In what year and in which Bitcoin improvement proposal Opcodes such as OP_MODE have been disabled?
FraMog
# In what year and in which Bitcoin improvement proposal Opcodes such as OP_MODE have been disabled?

(Asked by: username_0 on 2020-12-29)

On [Bitcoin wiki](https://en.bitcoin.it/wiki/Script) several opcodes are listed as "disabled".

My question is simple: which Bitcoin improvement proposal proposed to disable them, and when they have effectively been disabled in the past?

I'm particularly interested in the OP\_MOD arithmetic opcode.

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**Tags:** script, bip, opcodes


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## 1 answers

### Answer by username_1 on 2020-12-29. Score: 1

It appears many unused opcodes were disabled in 2010 for security reasons (at least OP\_CAT) or as a security precaution (many others).

[Pseudonymous](https://bitcoin.stackexchange.com/users/24925/pseudonymous) commented that the first BIPs didn't start until 2011 - a year later.


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