28 lines
		
	
	
		
			1.4 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
			
		
		
	
	
			28 lines
		
	
	
		
			1.4 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
| # Checksum Deprecation
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| 
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| During early 2015 Homebrew started the process of deprecating _SHA1_ for package
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| integrity verification. Since then every formulae under the Homebrew organisation
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| has been moved onto _SHA256_ verification; this includes both source packages
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| and our precompiled packages (bottles).
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| 
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| We also stopped supporting _MD5_ entirely. It was removed from core formulae in 2012 but until April 2015 if you tried to install a formula still using an
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| _MD5_ checksum Homebrew wouldn't actively stop you.
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| 
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| On _SHA1_ we added a `brew audit` check that flags _SHA1_ checksums as deprecated
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| and requests that you use _SHA256_.
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| 
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| We saw positive ecosystem engagement on moving from _MD5_ & _SHA1_ to the recommended _SHA256_ and thanks to that we're in a strong position to move forwards.
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| 
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| ## Moving forwards on SHA1.
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| 
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| From March 20th 2016 we've stepped up the visibility of that notification & you'll start
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| seeing deprecation warnings when installing _SHA1_-validated formula.
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| If you see these please consider reporting it to where the formula originated.
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| 
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| We're targeting **the end of September 2016** for _SHA1_ support removal,
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| 19 months after we started warning people to move away from it for verification.
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| This will be enforced in the same way _MD5_ is today, by blocking the installation of that individual formula until the checksum is migrated.
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| 
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| This means prior to that date custom taps, local custom formulae, etc
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| need to be migrated to use _SHA256_.
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