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b0fb4fb689
an example to OpenSSL::Digest. Patch by Sylvain Daubert. [Ruby 1.9 - Bug #5166] * ext/openssl/lib/openssl/digest.rb (module OpenSSL): ditto git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@33065 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
438 lines
11 KiB
C
438 lines
11 KiB
C
/*
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* $Id$
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* 'OpenSSL for Ruby' project
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* Copyright (C) 2001-2002 Michal Rokos <m.rokos@sh.cvut.cz>
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* All rights reserved.
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*/
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/*
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* This program is licenced under the same licence as Ruby.
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* (See the file 'LICENCE'.)
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*/
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#include "ossl.h"
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#define GetDigest(obj, ctx) do { \
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Data_Get_Struct((obj), EVP_MD_CTX, (ctx)); \
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if (!(ctx)) { \
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ossl_raise(rb_eRuntimeError, "Digest CTX wasn't initialized!"); \
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} \
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} while (0)
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#define SafeGetDigest(obj, ctx) do { \
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OSSL_Check_Kind((obj), cDigest); \
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GetDigest((obj), (ctx)); \
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} while (0)
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/*
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* Classes
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*/
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VALUE cDigest;
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VALUE eDigestError;
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static VALUE ossl_digest_alloc(VALUE klass);
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/*
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* Public
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*/
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const EVP_MD *
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GetDigestPtr(VALUE obj)
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{
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const EVP_MD *md;
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ASN1_OBJECT *oid = NULL;
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if (TYPE(obj) == T_STRING) {
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const char *name = StringValueCStr(obj);
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md = EVP_get_digestbyname(name);
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if (!md) {
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oid = OBJ_txt2obj(name, 0);
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md = EVP_get_digestbyobj(oid);
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ASN1_OBJECT_free(oid);
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}
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if(!md)
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ossl_raise(rb_eRuntimeError, "Unsupported digest algorithm (%s).", name);
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} else {
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EVP_MD_CTX *ctx;
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SafeGetDigest(obj, ctx);
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md = EVP_MD_CTX_md(ctx);
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}
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return md;
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}
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VALUE
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ossl_digest_new(const EVP_MD *md)
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{
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VALUE ret;
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EVP_MD_CTX *ctx;
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ret = ossl_digest_alloc(cDigest);
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GetDigest(ret, ctx);
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if (EVP_DigestInit_ex(ctx, md, NULL) != 1) {
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ossl_raise(eDigestError, "Digest initialization failed.");
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}
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return ret;
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}
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/*
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* Private
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*/
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static VALUE
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ossl_digest_alloc(VALUE klass)
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{
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EVP_MD_CTX *ctx;
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VALUE obj;
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ctx = EVP_MD_CTX_create();
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if (ctx == NULL)
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ossl_raise(rb_eRuntimeError, "EVP_MD_CTX_create() failed");
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obj = Data_Wrap_Struct(klass, 0, EVP_MD_CTX_destroy, ctx);
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return obj;
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}
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VALUE ossl_digest_update(VALUE, VALUE);
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/*
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* call-seq:
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* Digest.new(string [, data]) -> Digest
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*
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* Creates a Digest instance based on +string+, which is either the ln
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* (long name) or sn (short name) of a supported digest algorithm.
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* If +data+ (a +String+) is given, it is used as the initial input to the
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* Digest instance, i.e.
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* digest = OpenSSL::Digest.new('sha256', 'digestdata')
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* is equal to
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* digest = OpenSSL::Digest.new('sha256')
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* digest.update('digestdata')
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*
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* === Example
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* digest = OpenSSL::Digest.new('sha1')
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*
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*
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*/
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static VALUE
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ossl_digest_initialize(int argc, VALUE *argv, VALUE self)
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{
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EVP_MD_CTX *ctx;
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const EVP_MD *md;
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VALUE type, data;
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rb_scan_args(argc, argv, "11", &type, &data);
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md = GetDigestPtr(type);
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if (!NIL_P(data)) StringValue(data);
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GetDigest(self, ctx);
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if (EVP_DigestInit_ex(ctx, md, NULL) != 1) {
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ossl_raise(eDigestError, "Digest initialization failed.");
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}
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if (!NIL_P(data)) return ossl_digest_update(self, data);
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return self;
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}
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static VALUE
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ossl_digest_copy(VALUE self, VALUE other)
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{
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EVP_MD_CTX *ctx1, *ctx2;
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rb_check_frozen(self);
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if (self == other) return self;
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GetDigest(self, ctx1);
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SafeGetDigest(other, ctx2);
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if (!EVP_MD_CTX_copy(ctx1, ctx2)) {
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ossl_raise(eDigestError, NULL);
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}
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return self;
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}
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/*
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* call-seq:
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* digest.reset -> self
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*
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* Resets the Digest in the sense that any Digest#update that has been
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* performed is abandoned and the Digest is set to its initial state again.
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*
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*/
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static VALUE
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ossl_digest_reset(VALUE self)
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{
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EVP_MD_CTX *ctx;
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GetDigest(self, ctx);
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if (EVP_DigestInit_ex(ctx, EVP_MD_CTX_md(ctx), NULL) != 1) {
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ossl_raise(eDigestError, "Digest initialization failed.");
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}
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return self;
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}
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/*
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* call-seq:
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* digest.update(string) -> aString
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*
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* Not every message digest can be computed in one single pass. If a message
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* digest is to be computed from several subsequent sources, then each may
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* be passed individually to the Digest instance.
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*
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* === Example
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* digest = OpenSSL::Digest::SHA256.new
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* digest.update('First input')
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* digest << 'Second input' # equivalent to digest.update('Second input')
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* result = digest.digest
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*
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*/
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VALUE
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ossl_digest_update(VALUE self, VALUE data)
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{
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EVP_MD_CTX *ctx;
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StringValue(data);
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GetDigest(self, ctx);
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EVP_DigestUpdate(ctx, RSTRING_PTR(data), RSTRING_LEN(data));
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return self;
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}
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/*
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* call-seq:
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* digest.finish -> aString
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*
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*/
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static VALUE
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ossl_digest_finish(int argc, VALUE *argv, VALUE self)
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{
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EVP_MD_CTX *ctx;
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VALUE str;
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rb_scan_args(argc, argv, "01", &str);
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GetDigest(self, ctx);
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if (NIL_P(str)) {
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str = rb_str_new(NULL, EVP_MD_CTX_size(ctx));
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} else {
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StringValue(str);
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rb_str_resize(str, EVP_MD_CTX_size(ctx));
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}
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EVP_DigestFinal_ex(ctx, (unsigned char *)RSTRING_PTR(str), NULL);
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return str;
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}
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/*
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* call-seq:
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* digest.name -> string
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*
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* Returns the sn of this Digest instance.
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*
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* === Example
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* digest = OpenSSL::Digest::SHA512.new
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* puts digest.name # => SHA512
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*
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*/
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static VALUE
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ossl_digest_name(VALUE self)
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{
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EVP_MD_CTX *ctx;
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GetDigest(self, ctx);
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return rb_str_new2(EVP_MD_name(EVP_MD_CTX_md(ctx)));
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}
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/*
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* call-seq:
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* digest.digest_length -> integer
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*
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* Returns the output size of the digest, i.e. the length in bytes of the
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* final message digest result.
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*
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* === Example
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* digest = OpenSSL::Digest::SHA1.new
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* puts digest.digest_length # => 20
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*
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*/
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static VALUE
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ossl_digest_size(VALUE self)
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{
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EVP_MD_CTX *ctx;
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GetDigest(self, ctx);
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return INT2NUM(EVP_MD_CTX_size(ctx));
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}
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/*
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* call-seq:
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* digest.block_length -> integer
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*
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* Returns the block length of the digest algorithm, i.e. the length in bytes
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* of an individual block. Most modern algorithms partition a message to be
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* digested into a sequence of fix-sized blocks that are processed
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* consecutively.
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*
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* === Example
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* digest = OpenSSL::Digest::SHA1.new
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* puts digest.block_length # => 64
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*/
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static VALUE
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ossl_digest_block_length(VALUE self)
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{
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EVP_MD_CTX *ctx;
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GetDigest(self, ctx);
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return INT2NUM(EVP_MD_CTX_block_size(ctx));
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}
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/*
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* INIT
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*/
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void
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Init_ossl_digest()
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{
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rb_require("digest");
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#if 0
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mOSSL = rb_define_module("OpenSSL"); /* let rdoc know about mOSSL */
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#endif
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/* Document-class: OpenSSL::Digest
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*
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* OpenSSL::Digest allows you to compute message digests (sometimes
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* interchangeably called "hashes") of arbitrary data that are
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* cryptographically secure, i.e. a Digest implements a secure one-way
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* function.
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*
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* One-way functions offer some useful properties. E.g. given two
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* distinct inputs the probability that both yield the same output
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* is highly unlikely. Combined with the fact that every message digest
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* algorithm has a fixed-length output of just a few bytes, digests are
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* often used to create unique identifiers for arbitrary data. A common
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* example is the creation of a unique id for binary documents that are
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* stored in a database.
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*
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* Another useful characteristic of one-way functions (and thus the name)
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* is that given a digest there is no indication about the original
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* data that produced it, i.e. the only way to identify the original input
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* is to "brute-force" through every possible combination of inputs.
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*
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* These characteristics make one-way functions also ideal companions
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* for public key signature algorithms: instead of signing an entire
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* document, first a hash of the document is produced with a considerably
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* faster message digest algorithm and only the few bytes of its output
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* need to be signed using the slower public key algorithm. To validate
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* the integrity of a signed document, it suffices to re-compute the hash
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* and verify that it is equal to that in the signature.
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*
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* Among the supported message digest algorithms are:
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* * SHA, SHA1, SHA224, SHA256, SHA384 and SHA512
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* * MD2, MD4, MDC2 and MD5
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* * RIPEMD160
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* * DSS, DSS1 (Pseudo algorithms to be used for DSA signatures. DSS is
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* equal to SHA and DSS1 is equal to SHA1)
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*
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* For each of these algorithms, there is a sub-class of Digest that
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* can be instantiated as simply as e.g.
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*
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* digest = OpenSSL::Digest::SHA1.new
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*
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* === Mapping between Digest class and sn/ln
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*
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* The sn (short names) and ln (long names) are defined in
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* <openssl/object.h> and <openssl/obj_mac.h>. They are textual
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* representations of ASN.1 OBJECT IDENTIFIERs. Each supported digest
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* algorithm has an OBJECT IDENTIFIER associated to it and those again
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* have short/long names assigned to them.
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* E.g. the OBJECT IDENTIFIER for SHA-1 is 1.3.14.3.2.26 and its
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* sn is "SHA1" and its ln is "sha1".
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* ==== MD2
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* * sn: MD2
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* * ln: md2
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* ==== MD4
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* * sn: MD4
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* * ln: md4
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* ==== MD5
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* * sn: MD5
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* * ln: md5
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* ==== SHA
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* * sn: SHA
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* * ln: SHA
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* ==== SHA-1
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* * sn: SHA1
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* * ln: sha1
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* ==== SHA-224
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* * sn: SHA224
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* * ln: sha224
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* ==== SHA-256
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* * sn: SHA256
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* * ln: sha256
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* ==== SHA-384
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* * sn: SHA384
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* * ln: sha384
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* ==== SHA-512
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* * sn: SHA512
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* * ln: sha512
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*
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* "Breaking" a message digest algorithm means defying its one-way
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* function characteristics, i.e. producing a collision or finding a way
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* to get to the original data by means that are more efficient than
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* brute-forcing etc. Most of the supported digest algorithms can be
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* considered broken in this sense, even the very popular MD5 and SHA1
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* algorithms. Should security be your highest concern, then you should
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* probably rely on SHA224, SHA256, SHA384 or SHA512.
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*
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* === Hashing a file
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*
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* data = File.read('document')
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* sha256 = OpenSSL::Digest::SHA256.new
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* digest = sha256.digest(data)
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*
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* === Hashing several pieces of data at once
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*
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* data1 = File.read('file1')
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* data2 = File.read('file2')
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* data3 = File.read('file3')
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* sha256 = OpenSSL::Digest::SHA256.new
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* sha256 << data1
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* sha256 << data2
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* sha256 << data3
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* digest = sha256.digest
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*
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* === Reuse a Digest instance
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*
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* data1 = File.read('file1')
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* sha256 = OpenSSL::Digest::SHA256.new
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* digest1 = sha256.digest(data1)
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*
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* data2 = File.read('file2')
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* sha256.reset
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* digest2 = sha256.digest(data2)
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*
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*/
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cDigest = rb_define_class_under(mOSSL, "Digest", rb_path2class("Digest::Class"));
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/* Document-class: OpenSSL::Digest::DigestError
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*
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* Generic Exception class that is raised if an error occurs during a
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* Digest operation.
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*/
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eDigestError = rb_define_class_under(cDigest, "DigestError", eOSSLError);
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rb_define_alloc_func(cDigest, ossl_digest_alloc);
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rb_define_method(cDigest, "initialize", ossl_digest_initialize, -1);
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rb_define_copy_func(cDigest, ossl_digest_copy);
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rb_define_method(cDigest, "reset", ossl_digest_reset, 0);
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rb_define_method(cDigest, "update", ossl_digest_update, 1);
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rb_define_alias(cDigest, "<<", "update");
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rb_define_private_method(cDigest, "finish", ossl_digest_finish, -1);
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rb_define_method(cDigest, "digest_length", ossl_digest_size, 0);
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rb_define_method(cDigest, "block_length", ossl_digest_block_length, 0);
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rb_define_method(cDigest, "name", ossl_digest_name, 0);
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}
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