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authorHerbert Xu <herbert@gondor.apana.org.au>2008-11-02 16:38:11 +0300
committerHerbert Xu <herbert@gondor.apana.org.au>2008-12-25 03:01:30 +0300
commitdec8b78606ebd5f309c38f2fb10196ce996dd18d (patch)
tree005ef526f1b0e953a3a57e6c991e0921fcd5234b /crypto/shash.c
parent3b2f6df08258e2875f42bd630eece7e7241a053b (diff)
downloadlinux-dec8b78606ebd5f309c38f2fb10196ce996dd18d.tar.xz
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.c14
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)
{