Tspi_Hash_Sign(3)

💖 Tspi_Hash_Sign(3) 💖

okay bestie, welcome to the TCG Software Stack Developer's Reference — this is the Tspi_Hash_Sign(3) page from the Library Functions Manual, and it's literally the moment your hash data gets its signature glow-up. no cap. 🦋

✨ NAME ✨

Tspi_Hash_Sign — sign the hash data of an object with a signing key

like. that's it. that's the whole job. sign the hash data of an object with a signing key. iconic behavior. 💅

🌸 SYNOPSIS 🌸

#include <tss/platform.h>
#include <tss/tcpa_defines.h>
#include <tss/tcpa_typedef.h>
#include <tss/tcpa_struct.h>
#include <tss/tss_typedef.h>
#include <tss/tss_structs.h>
#include <tss/tspi.h>

TSS_RESULT Tspi_Hash_Sign(TSS_HHASH hHash,              TSS_HKEY hKey,
                          UINT32    pulSignatureLength, BYTE**   prgbSignature);

all those includes? yeah you need every single one of them, don't @ me, just copy them in. 🙈

🎀 DESCRIPTION 🎀

so Tspi_Hash_Sign signs the hash data of an object with a given signing key. simple. elegant. the way that it just does the thing. 🔥

BUT — and this is the part where you gotta pay attention, bestie — the data must be set at the hash instance associated with hHash by calling Tspi_Hash_SetHashValue or Tspi_Hash_UpdateHashValue. no data, no signature. it's giving "you have to actually put something in before you ask for something out." 💀

also real talk: the Tspi_Hash_Sign method allocates a memory block for the prgbSignature data. so that memory is yours now, and you must release it using Tspi_Context_FreeMemory. do not ghost that memory block. free it. it's the respectful thing to do. 🫶

🌈 PARAMETERS 🌈

💜 hHash

The handle to the hash object instance whose hash value should be signed.

like, which hash are we signing here, girlie. this is that one.

💜 hKey

Handle to the key object which should be used for the signature.

the signing key. the main character of this whole operation tbh. 👑

💜 pulSignatureLength

Receives the length of the signature data returned at the parameter prgbSignature on successful completion.

it's an out-param! it catches the length of the signature for you once everything works. ✨

💜 prgbSignature

Receives a pointer to the signature data on successful completion.

and this one catches the actual pointer to the signature data. and again — free that memory with Tspi_Context_FreeMemory, bestie, i am begging. 😭

⭐ RETURN CODES ⭐

Tspi_Hash_Sign returns TSS_SUCCESS on success (slay 🎉), otherwise one of the following values is returned:

• TSS_E_INVALID_HANDLE — hKey is not a valid handle. like it's just not valid. nope. 🙅
• TSS_E_INTERNAL_ERROR — An internal SW error has been detected. not our fault, it's the internals being messy.
• TSS_E_BAD_PARAMETER — One or more parameters is bad. something you passed in is misbehaving.
• TSS_E_HASH_INVALID_LENGTH — Hash length is inconsistent with hash algorithm. the length and the algorithm are not matching each other's energy. 💀
• TSS_E_HASH_NO_DATA — Hash object has no internal hash value. empty. void. nothing in there. go call Tspi_Hash_SetHashValue or Tspi_Hash_UpdateHashValue first fr fr.
• TSS_E_HASH_NO_IDENTIFIER — The hash algorithm identifier is not set. it doesn't even know what algorithm it is. identity crisis core. 😭

👑 CONFORMING TO 👑

Tspi_Hash_Sign conforms to the Trusted Computing Group Software Specification version 1.1 Golden

periodt. that's the spec, that's the standard, that's the vibe. ✅

🦋 SEE ALSO 🦋

• Tspi_Hash_UpdateHashValue(3)
• Tspi_Hash_SetHashValue(3)
• Tspi_Hash_VerifySignature(3)

go read those too, they're all part of the same little friend group. iykyk. 💖

and that's the page, bestie!! this one's from TSS 1.1, dated 2004-05-25 — yeah she's an elder but she still eats. go sign something. responsibly. and FREE YOUR MEMORY. 🎀✨💅