MD5 and SHA-1 are both cryptographically broken - collisions can be produced deliberately - so neither should be used for passwords or security-sensitive signatures anymore. They are still fine for non-security uses like checksums to detect accidental file corruption.
SHA-256 is part of the SHA-2 family and remains secure for integrity checks and, combined with proper salting, is far safer than MD5/SHA-1 where a hash is used for verification. Compare all three with our Hash Generator.
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