# Digest::SHA

📦 std

Compute SHA-1 and SHA-2 family message digests: SHA-1, SHA-224, SHA-256, SHA-384, SHA-512, SHA-512/224, and SHA-512/256, with optional HMAC keying. Two call styles are available. The **functional interface** (`sha256_hex`, `hmac_sha512_base64`, and friends) is a one-shot: hand it the data, get the digest back. The **object interface** (`Digest::SHA->new(256)`, `->add`, `->digest`) lets you feed data incrementally — from streams, files, or a mix of sources — and finalize when you are ready. Every digest can be rendered in three encodings: raw binary (fixed-length bytes), lowercase hex, or unpadded Base64. Choose the encoding by the function suffix (`_hex`, `_base64`, or none for raw). HMAC variants use the same suffixes and live under the `hmac_*` prefix. File input is supported through `addfile`, which reads a filehandle or filename and feeds its contents straight into the context. A `bits` helper (`add_bits`) lets you hash arbitrary-length bit strings, not just whole bytes. Context state is serialisable with `getstate` / `putstate` (text) and `_getstate` / `_putstate` (packed binary), so a long-running hash can be suspended and resumed across processes. Pick **SHA-256** by default for new work: it is fast on 32-bit and 64-bit CPUs alike and has the widest interoperability. Prefer **SHA-512** (or its truncated `SHA-512/256` cousin) on 64-bit hardware when you want more performance headroom or a larger internal state; SHA-512 often outperforms SHA-256 there despite the larger output. Avoid **SHA-1** for anything collision-sensitive — it survives only for legacy interoperability. ## Functions ### Functional digests #### [`sha_functional`](SHA/sha_functional.md) Compute a SHA digest of the concatenated arguments in one call. ### OO lifecycle #### [`newSHA`](SHA/newSHA.md) Construct a fresh `Digest::SHA` object for the given algorithm number. #### [`new`](SHA/new.md) Construct or reinitialise a `Digest::SHA` object. #### [`clone`](SHA/clone.md) Copy a `Digest::SHA` object, producing an independent duplicate. #### [`destroy`](SHA/destroy.md) Release the native context attached to a `Digest::SHA` object. #### [`reset`](SHA/reset.md) Rewind a `Digest::SHA` object, optionally switching algorithm. ### OO input #### [`add`](SHA/add.md) Feed byte data into a `Digest::SHA` object incrementally. #### [`add_bits`](SHA/add_bits.md) Feed an arbitrary number of bits into a `Digest::SHA` object. #### [`addfilebin`](SHA/addfilebin.md) Feed the raw byte contents of a filehandle into a `Digest::SHA` object. #### [`addfileuniv`](SHA/addfileuniv.md) Feed a filehandle’s contents into a `Digest::SHA` object, reading through the PerlIO text layer. #### [`addfile`](SHA/addfile.md) Feed a filehandle or a file by name into a `Digest::SHA` object. ### OO output #### [`digest`](SHA/digest.md) Finalise the running hash and return the raw binary digest. #### [`hexdigest`](SHA/hexdigest.md) Finalise the running hash and return the digest as a lowercase hex string. #### [`b64digest`](SHA/b64digest.md) Finalise the running hash and return the digest as an unpadded Base64 string. #### [`algorithm`](SHA/algorithm.md) Return the algorithm code of a `Digest::SHA` object. #### [`hashsize`](SHA/hashsize.md) Return the digest length of a `Digest::SHA` object in bits. ### HMAC #### [`hmac_functional`](SHA/hmac_functional.md) Compute a keyed HMAC digest of the data arguments in one call. ### State export #### [`getstate`](SHA/getstate.md) Export a `Digest::SHA` object’s state as a packed binary string. #### [`putstate`](SHA/putstate.md) Restore a `Digest::SHA` object’s state from a packed binary string. #### [`getstate_text`](SHA/getstate_text.md) Export a `Digest::SHA` object’s state as a human-readable text string. #### [`putstate_text`](SHA/putstate_text.md) Construct or restore a `Digest::SHA` object from a text state string. #### [`dump`](SHA/dump.md) Write the current `Digest::SHA` state to a file or STDOUT in text form. #### [`load`](SHA/load.md) Construct a `Digest::SHA` object from a text state file written by `dump`.