More OpenSSL and documenation fun. No more words to say. (0.38.13)

docs/external/openssl.md

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+# OpenSSL extension (optional)
+
+- CMake option: FUN_WITH_OPENSSL=ON
+- Purpose: provide small crypto helpers backed by OpenSSL. Includes md5, sha256, sha512 helpers.
+- Homepage: https://www.openssl.org/
+
+Build notes:
+- Requires system OpenSSL development headers and libraries.
+- On OpenSSL 3.x, legacy MD5_* APIs are deprecated; you may see warnings during build.
+
+Provided helper/opcodes:
+- Function: openssl_md5(data:string) -> string (lowercase hex). Falls back to empty string when the extension is disabled, mirroring other optional modules.
+- Function: openssl_sha256(data:string) -> string (lowercase hex).
+- Function: openssl_sha512(data:string) -> string (lowercase hex).
+- Opcodes: OP_OPENSSL_MD5, OP_OPENSSL_SHA256, OP_OPENSSL_SHA512 (internal mappings for the functions above).
+
+Quickstart:
+- Configure: cmake -S . -B build -DFUN_WITH_OPENSSL=ON
+- Build: cmake --build build --target fun
+- Run examples:
+  - ./build/fun examples/crypto/openssl_md5.fun
+  - ./build/fun examples/crypto/openssl_sha256.fun
+  - ./build/fun examples/crypto/openssl_sha512.fun
+
+Example output:
+- md5(abc) = 900150983cd24fb0d6963f7d28e17f72
+- md5("") = d41d8cd98f00b204e9800998ecf8427e
+- sha256(abc) = ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad
+- sha256("") = e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+- sha512(abc) = ddaf35a193617abacc417349ae20413112e6fa4e89a97ea20a9eeee64b55d39a2192992a274fc1a836ba3c23a3feebbd454d4423643ce80e2a9ac94fa54ca49f
+- sha512("") = cf83e1357eefb8bdf1542850d66d8007d620e4050b5715dc83f4a921d36ce9ce47d0d13c5d85f2b0ff8318d2877eec2f63b931bd47417a81a538327af927da3e