path: root/crypto/shash.c
diff options
authorHerbert Xu <herbert@gondor.apana.org.au>2008-11-02 21:38:11 +0800
committerHerbert Xu <herbert@gondor.apana.org.au>2008-12-25 11:01:30 +1100
commitdec8b78606ebd5f309c38f2fb10196ce996dd18d (patch)
tree005ef526f1b0e953a3a57e6c991e0921fcd5234b /crypto/shash.c
parent3b2f6df08258e2875f42bd630eece7e7241a053b (diff)
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')
1 files changed, 14 insertions, 0 deletions
diff --git a/crypto/shash.c b/crypto/shash.c
index 3f4c713a21e..26aff3feefc 100644
--- a/crypto/shash.c
+++ b/crypto/shash.c
@@ -172,6 +172,20 @@ int crypto_shash_digest(struct shash_desc *desc, const u8 *data,
+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;
static int shash_async_setkey(struct crypto_ahash *tfm, const u8 *key,
unsigned int keylen)