1 files changed, 167 insertions, 0 deletions

diff --git a/src/lib/libcrypto/man/EVP_SignInit.3 b/src/lib/libcrypto/man/EVP_SignInit.3
new file mode 100644
index 0000000000..22f81148a2
--- /dev/null
+++ b/src/lib/libcrypto/man/EVP_SignInit.3
@@ -0,0 +1,167 @@
+.Dd $Mdocdate: November 3 2016 $
+.Dt EVP_SIGNINIT 3
+.Os
+.Sh NAME
+.Nm EVP_SignInit ,
+.Nm EVP_SignUpdate ,
+.Nm EVP_SignFinal ,
+.Nm EVP_PKEY_size
+.Nd EVP signing functions
+.Sh SYNOPSIS
+.In openssl/evp.h
+.Ft int
+.Fo EVP_SignInit_ex
+.Fa "EVP_MD_CTX *ctx"
+.Fa "const EVP_MD *type"
+.Fa "ENGINE *impl"
+.Fc
+.Ft int
+.Fo EVP_SignUpdate
+.Fa "EVP_MD_CTX *ctx"
+.Fa "const void *d"
+.Fa "unsigned int cnt"
+.Fc
+.Ft int
+.Fo EVP_SignFinal
+.Fa "EVP_MD_CTX *ctx"
+.Fa "unsigned char *sig"
+.Fa "unsigned int *s"
+.Fa "EVP_PKEY *pkey"
+.Fc
+.Ft void
+.Fo EVP_SignInit
+.Fa "EVP_MD_CTX *ctx"
+.Fa "const EVP_MD *type"
+.Fc
+.Ft int
+.Fo EVP_PKEY_size
+.Fa "EVP_PKEY *pkey"
+.Fc
+.Sh DESCRIPTION
+The EVP signature routines are a high level interface to digital
+signatures.
+.Pp
+.Fn EVP_SignInit_ex
+sets up a signing context
+.Fa ctx
+to use the digest
+.Fa type
+from
+.Vt ENGINE
+.Fa impl .
+.Fa ctx
+must be initialized with
+.Xr EVP_MD_CTX_init 3
+before calling this function.
+.Pp
+.Fn EVP_SignUpdate
+hashes
+.Fa cnt
+bytes of data at
+.Fa d
+into the signature context
+.Fa ctx .
+This function can be called several times on the same
+.Fa ctx
+to include additional data.
+.Pp
+.Fn EVP_SignFinal
+signs the data in
+.Fa ctx
+using the private key
+.Fa pkey
+and places the signature in
+.Fa sig .
+.Fa sig
+must be at least
+.Fn EVP_PKEY_size pkey
+bytes in size.
+.Fa s
+is an OUT parameter, and not used as an IN parameter.
+The number of bytes of data written (i.e.
+the length of the signature) will be written to the integer at
+.Fa s .
+At most
+.Fn EVP_PKEY_size pkey
+bytes will be written.
+.Pp
+.Fn EVP_SignInit
+initializes a signing context
+.Fa ctx
+to use the default implementation of digest
+.Fa type .
+.Pp
+.Fn EVP_PKEY_size
+returns the maximum size of a signature in bytes.
+The actual signature returned by
+.Fn EVP_SignFinal
+may be smaller.
+.Pp
+The EVP interface to digital signatures should almost always be
+used in preference to the low level interfaces.
+This is because the code then becomes transparent to the algorithm used
+and much more flexible.
+.Pp
+Due to the link between message digests and public key algorithms the
+correct digest algorithm must be used with the correct public key type.
+A list of algorithms and associated public key algorithms appears in
+.Xr EVP_DigestInit 3 .
+.Pp
+The call to
+.Fn EVP_SignFinal
+internally finalizes a copy of the digest context.
+This means that calls to
+.Fn EVP_SignUpdate
+and
+.Fn EVP_SignFinal
+can be called later to digest and sign additional data.
+.Pp
+Since only a copy of the digest context is ever finalized, the context
+must be cleaned up after use by calling
+.Xr EVP_MD_CTX_cleanup 3
+or a memory leak will occur.
+.Sh RETURN VALUES
+.Fn EVP_SignInit_ex ,
+.Fn EVP_SignUpdate ,
+and
+.Fn EVP_SignFinal
+return 1 for success and 0 for failure.
+.Pp
+.Fn EVP_PKEY_size
+returns the maximum size of a signature in bytes.
+.Pp
+The error codes can be obtained by
+.Xr ERR_get_error 3 .
+.Sh SEE ALSO
+.Xr ERR 3 ,
+.Xr evp 3 ,
+.Xr EVP_DigestInit 3 ,
+.Xr EVP_VerifyInit 3
+.Sh HISTORY
+.Fn EVP_SignInit ,
+.Fn EVP_SignUpdate ,
+and
+.Fn EVP_SignFinal
+are available in all versions of SSLeay and OpenSSL.
+.Pp
+.Fn EVP_SignInit_ex
+was added in OpenSSL 0.9.7.
+.Sh BUGS
+Older versions of this documentation wrongly stated that calls to
+.Fn EVP_SignUpdate
+could not be made after calling
+.Fn EVP_SignFinal .
+.Pp
+Since the private key is passed in the call to
+.Fn EVP_SignFinal
+any error relating to the private key (for example an unsuitable key and
+digest combination) will not be indicated until after potentially large
+amounts of data have been passed through
+.Fn EVP_SignUpdate .
+.Pp
+It is not possible to change the signing parameters using these
+function.
+.Pp
+The previous two bugs are fixed in the newer
+.Xr EVP_SignDigest* 3
+function.