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| author | Herbert Xu <herbert@gondor.apana.org.au> | 2008-11-02 21:38:11 +0800 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2008-12-25 11:01:30 +1100 |
| commit | dec8b78606ebd5f309c38f2fb10196ce996dd18d (patch) | |
| tree | 005ef526f1b0e953a3a57e6c991e0921fcd5234b /crypto/shash.c | |
| parent | 3b2f6df08258e2875f42bd630eece7e7241a053b (diff) | |
| download | lwn-dec8b78606ebd5f309c38f2fb10196ce996dd18d.tar.gz lwn-dec8b78606ebd5f309c38f2fb10196ce996dd18d.zip | |
crypto: hash - Add import/export interface
It is often useful to save the partial state of a hash function
so that it can be used as a base for two or more computations.
The most prominent example is HMAC where all hashes start from
a base determined by the key. Having an import/export interface
means that we only have to compute that base once rather than
for each message.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto/shash.c')
| -rw-r--r-- | crypto/shash.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/crypto/shash.c b/crypto/shash.c index 3f4c713a21ea..26aff3feefc0 100644 --- a/crypto/shash.c +++ b/crypto/shash.c @@ -172,6 +172,20 @@ int crypto_shash_digest(struct shash_desc *desc, const u8 *data, } EXPORT_SYMBOL_GPL(crypto_shash_digest); +int crypto_shash_import(struct shash_desc *desc, const u8 *in) +{ + struct crypto_shash *tfm = desc->tfm; + struct shash_alg *alg = crypto_shash_alg(tfm); + + memcpy(shash_desc_ctx(desc), in, crypto_shash_descsize(tfm)); + + if (alg->reinit) + alg->reinit(desc); + + return 0; +} +EXPORT_SYMBOL_GPL(crypto_shash_import); + static int shash_async_setkey(struct crypto_ahash *tfm, const u8 *key, unsigned int keylen) { |