# SVC_SHA1Update

## Syntax

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

      void SVC_SHA1Update( SVCSHA1Context *context,
                             const void* data,
                             unsigned long len );

## Arguments

context | Pointer to the context structure used for SHA-1 generation.
data | Pointer to the input data.
len | Size of the input data.

## Return Values

None.

## Description

This function updates the SHA-1 digest value based on the input data.

context must be initialized beforehand with `SVC_SHA1Init()`.

Call this function as many times as needed, and then use the `SVC_SHA1GetHash` function to obtain the digest value. Specify the input data using data and len. Any size and alignment position can be used.

SHA-1 is an algorithm to find the message digest value. For details, see RFC (Request For Comments) 3174, which is published by IETF (the Internet Engineering Task Force).

## See Also

`SVC_SHA1Init`, `SVC_SHA1GetHash`

## Revision History

2007/10/19 Initial version.

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