# SVC_HMACSHA1GetHash

## Syntax

      #include <twl/os/common/systemCall.h>

      void SVC_SHA1GetHash( SVCHMACSHA1Context *context,
                             void* md );

## Arguments

context | Pointer to the context structure for HMAC-SHA1 generation.
md | Pointer to the memory location that holds the message digest value.

## Return Values

None.

## Description

Gets the HMAC-SHA1 digest value.

Use the `SVC_HMACSHA1Init` function to initialize the context argument and then use the `SVC_HMACSHA1Update` function to provide the input data.

The length of the generated message digest value is 160 bits, or `SVC_SHA1_DIGEST_SIZE` (= 20) bytes. Use the md argument to pass an area that can store a value of this size.

This function rewrites `context` internally, so you cannot continue to use the same context with the `SVC_HMACSHA1Update` function.

## See Also

`SVC_HMACSHA1Init`, `SVC_HMACSHA1Update`, `SVC_SHA1GetHash`

## Revision History

2007/10/24 Initial version.

CONFIDENTIAL