In a new support document, Apple has indicated that macOS Catalina and iOS 13 drop support for TLS certificates signed with the SHA-1 hash algorithm, which is now considered to be insecure. SHA-2 is now required at a minimum.
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Apple says all TLS server certificates must comply with these new security requirements in macOS Catalina and iOS 13:
- TLS server certificates and issuing CAs using RSA keys must use key sizes greater than or equal to 2048 bits. Certificates using RSA key sizes smaller than 2048 bits are no longer trusted for TLS.
- TLS server certificates and issuing CAs must use a hash algorithm from the SHA-2 family in the signature algorithm. SHA-1 signed certificates are no longer trusted for TLS.
- TLS server certificates must present the DNS name of the server in the Subject Alternative Name extension of the certificate. DNS names in the CommonName of a certificate are no longer trusted.
Effective immediately, any connections to TLS servers violating these new requirements will fail and may cause network failures, apps to fail, and websites to not load in Safari in macOS Catalina and iOS 13, according to Apple.
Google, Microsoft, and Mozilla all deprecated SHA-1 certificates in 2017.
Top Rated Comments
For an insecure encryption algorithm? I would hope they'd deprecate it (following Google, Firefox etc.).
Encryption algorithms have shelf lives, more or less. Weaknesses are periodically discovered that make them vulnerable to cracking or workarounds, as in this case. Generally these problems cannot be fixed in the way ordinary software is patched because the problems are not specific to any vendor and are simply fundamental flaws in the encryption mechanism; the only solution is abandonment of the encryption method and moving on to safer methods.
SHA-1 is over 25 years old and has been known to have problems since at least 2005. Deprecating encryption methods that are known to be too weak or vulnerable is the right thing to do, and if anything, this move is long overdue.
[doublepost=1559832487][/doublepost]I miss Netscape. ;)
I have to laugh at the 40-bit encryption we used in the late 90s (32-bit in some parts of the world). It wasn't thought overly safe even at the time, but that seems just silly, today.