# hash(string:) Computes a SHA-256 digest of a Swift `String` encoded as UTF-8. ``` static func hash(string: String) -> SHA256.SHA256Digest ``` ## Parameters `string` The text to hash. UTF-8 encoding is applied unconditionally; callers needing a different encoding should call [`hash(data:)`](/documentation/OpenSSL/SHA256/hash(data:)) with explicitly encoded bytes. ## Return Value A [`SHA256.SHA256Digest`](/documentation/OpenSSL/SHA256/SHA256Digest) of exactly 32 bytes. ## Discussion A convenience over [`hash(data:)`](/documentation/OpenSSL/SHA256/hash(data:)) that hashes the bytes returned by `Data(string.utf8)`. Behavior is identical to hashing those bytes directly; the return type, length, and test-vector conformance (RFC 6234, FIPS 180-4) are the same. > Warning: SHA-256 hashes a byte sequence, not a semantic string. > Two visually identical strings with different Unicode > normalization forms (NFC vs NFD) produce different digests. When > the input may come from user-visible text — filenames, labels, > display names — normalize explicitly (for example with > `String.precomposedStringWithCanonicalMapping`) before hashing. > See [UAX No. 15](https://www.unicode.org/reports/tr15/) for the > normalization forms.