llSHA256String

string llSHA256String(string text)

Returns a string of 64 hex characters that is the SHA256 security hash of text.

Parameters

Technical Details

llSay(0, llSHA256String("Hello, Avatar!")); // returns 3a9f9d2e4360319a62139d19bd425c16fb8439b832d74d5221ca75b54c35b4f2

You can verify SHA-256 hashes using OpenSSL:

$ echo -n 'Hello, Avatar!' | openssl sha256
3a9f9d2e4360319a62139d19bd425c16fb8439b832d74d5221ca75b54c35b4f2

Caveats

There is no way to input a zero-byte value into this function, nor any byte value from 128-255, making it currently broken for many purposes (like HMAC-SHA1).
LSL strings cannot contain a Unicode null character (U+0000), and LSL has no escape code for the null character (unlike many programming languages that use \0).
llEscapeURL("%00") yields an empty string, providing no workaround.
Characters with a Unicode integer value over U+0127 (127 decimal) are handled in UTF-8 fashion: in the hex values, 0xC2 is prepended to the byte value (hence 0x0080-0x00FF become 0xC280-0xC2FF inside the function).

LSL strings are stored in UTF-8 format, which affects how byte values are encoded when passed to this function.

Prior to this function’s availability, the only way to get a SHA-256 hash was to use the LSL SHA-256 port implementation.