diff --git a/.rubocop.yml b/.rubocop.yml
index 99209b607b..9ad57dd51c 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -33,6 +33,10 @@ Lint/AssignmentInCondition:
 Lint/BooleanSymbol:
   Enabled: false
 
+Lint/DeprecatedOpenSSLConstant:
+  Exclude:
+    - library/openssl/digest/**/*.rb
+
 Lint/InterpolationCheck:
   Enabled: false
 
diff --git a/library/openssl/digest/append_spec.rb b/library/openssl/digest/append_spec.rb
new file mode 100644
index 0000000000..08802b7253
--- /dev/null
+++ b/library/openssl/digest/append_spec.rb
@@ -0,0 +1,6 @@
+require_relative '../../../spec_helper'
+require_relative 'shared/update'
+
+describe "OpenSSL::Digest#<<" do
+  it_behaves_like :openssl_digest_update, :<<
+end
diff --git a/library/openssl/digest/block_length_spec.rb b/library/openssl/digest/block_length_spec.rb
new file mode 100644
index 0000000000..444ed9d20d
--- /dev/null
+++ b/library/openssl/digest/block_length_spec.rb
@@ -0,0 +1,44 @@
+require_relative '../../../spec_helper'
+require_relative '../../../library/digest/sha1/shared/constants'
+require_relative '../../../library/digest/sha256/shared/constants'
+require_relative '../../../library/digest/sha384/shared/constants'
+require_relative '../../../library/digest/sha512/shared/constants'
+require 'openssl'
+
+describe "OpenSSL::Digest#block_length" do
+  context "when the digest object is created via a name argument" do
+    it "returns a SHA1 block length" do
+      OpenSSL::Digest.new('sha1').block_length.should == SHA1Constants::BlockLength
+    end
+
+    it "returns a SHA256 block length" do
+      OpenSSL::Digest.new('sha256').block_length.should == SHA256Constants::BlockLength
+    end
+
+    it "returns a SHA384 block length" do
+      OpenSSL::Digest.new('sha384').block_length.should == SHA384Constants::BlockLength
+    end
+
+    it "returns a SHA512 block length" do
+      OpenSSL::Digest.new('sha512').block_length.should == SHA512Constants::BlockLength
+    end
+  end
+
+  context "when the digest object is created via a subclass" do
+    it "returns a SHA1 block length" do
+      OpenSSL::Digest::SHA1.new.block_length.should == SHA1Constants::BlockLength
+    end
+
+    it "returns a SHA256 block length" do
+      OpenSSL::Digest::SHA256.new.block_length.should == SHA256Constants::BlockLength
+    end
+
+    it "returns a SHA384 block length" do
+      OpenSSL::Digest::SHA384.new.block_length.should == SHA384Constants::BlockLength
+    end
+
+    it "returns a SHA512 block length" do
+      OpenSSL::Digest::SHA512.new.block_length.should == SHA512Constants::BlockLength
+    end
+  end
+end
diff --git a/library/openssl/digest/digest_length_spec.rb b/library/openssl/digest/digest_length_spec.rb
new file mode 100644
index 0000000000..37d1cba9a7
--- /dev/null
+++ b/library/openssl/digest/digest_length_spec.rb
@@ -0,0 +1,44 @@
+require_relative '../../../spec_helper'
+require_relative '../../../library/digest/sha1/shared/constants'
+require_relative '../../../library/digest/sha256/shared/constants'
+require_relative '../../../library/digest/sha384/shared/constants'
+require_relative '../../../library/digest/sha512/shared/constants'
+require 'openssl'
+
+describe "OpenSSL::Digest#digest_length" do
+  context "when the digest object is created via a name argument" do
+    it "returns a SHA1 digest length" do
+      OpenSSL::Digest.new('sha1').digest_length.should == SHA1Constants::DigestLength
+    end
+
+    it "returns a SHA256 digest length" do
+      OpenSSL::Digest.new('sha256').digest_length.should == SHA256Constants::DigestLength
+    end
+
+    it "returns a SHA384 digest length" do
+      OpenSSL::Digest.new('sha384').digest_length.should == SHA384Constants::DigestLength
+    end
+
+    it "returns a SHA512 digest length" do
+      OpenSSL::Digest.new('sha512').digest_length.should == SHA512Constants::DigestLength
+    end
+  end
+
+  context "when the digest object is created via a subclass" do
+    it "returns a SHA1 digest length" do
+      OpenSSL::Digest::SHA1.new.digest_length.should == SHA1Constants::DigestLength
+    end
+
+    it "returns a SHA256 digest length" do
+      OpenSSL::Digest::SHA256.new.digest_length.should == SHA256Constants::DigestLength
+    end
+
+    it "returns a SHA384 digest length" do
+      OpenSSL::Digest::SHA384.new.digest_length.should == SHA384Constants::DigestLength
+    end
+
+    it "returns a SHA512 digest length" do
+      OpenSSL::Digest::SHA512.new.digest_length.should == SHA512Constants::DigestLength
+    end
+  end
+end
diff --git a/library/openssl/digest_spec.rb b/library/openssl/digest/digest_spec.rb
similarity index 84%
rename from library/openssl/digest_spec.rb
rename to library/openssl/digest/digest_spec.rb
index b8e82d073f..cf27d01b6d 100644
--- a/library/openssl/digest_spec.rb
+++ b/library/openssl/digest/digest_spec.rb
@@ -1,12 +1,11 @@
-require_relative '../../spec_helper'
-require_relative '../../library/digest/sha1/shared/constants'
-require_relative '../../library/digest/sha256/shared/constants'
-require_relative '../../library/digest/sha384/shared/constants'
-require_relative '../../library/digest/sha512/shared/constants'
+require_relative '../../../spec_helper'
+require_relative '../../../library/digest/sha1/shared/constants'
+require_relative '../../../library/digest/sha256/shared/constants'
+require_relative '../../../library/digest/sha384/shared/constants'
+require_relative '../../../library/digest/sha512/shared/constants'
 require 'openssl'
 
-describe "OpenSSL::Digest" do
-
+describe "OpenSSL::Digest class methods" do
   describe ".digest" do
     it "returns a SHA1 digest" do
       OpenSSL::Digest.digest('sha1', SHA1Constants::Contents).should == SHA1Constants::Digest
diff --git a/library/openssl/digest/initialize_spec.rb b/library/openssl/digest/initialize_spec.rb
new file mode 100644
index 0000000000..1cd0409c4d
--- /dev/null
+++ b/library/openssl/digest/initialize_spec.rb
@@ -0,0 +1,141 @@
+require_relative '../../../spec_helper'
+require_relative '../../../library/digest/sha1/shared/constants'
+require_relative '../../../library/digest/sha256/shared/constants'
+require_relative '../../../library/digest/sha384/shared/constants'
+require_relative '../../../library/digest/sha512/shared/constants'
+require 'openssl'
+
+describe "OpenSSL::Digest#initialize" do
+  describe "can be called with a digest name" do
+    it "returns a SHA1 object" do
+      OpenSSL::Digest.new("sha1").name.should == "SHA1"
+    end
+
+    it "returns a SHA256 object" do
+      OpenSSL::Digest.new("sha256").name.should == "SHA256"
+    end
+
+    it "returns a SHA384 object" do
+      OpenSSL::Digest.new("sha384").name.should == "SHA384"
+    end
+
+    it "returns a SHA512 object" do
+      OpenSSL::Digest.new("sha512").name.should ==  "SHA512"
+    end
+
+    it "throws an error when called with an unknown digest" do
+      -> { OpenSSL::Digest.new("wd40") }.should raise_error(RuntimeError, /Unsupported digest algorithm \(wd40\)/)
+    end
+
+    it "cannot be called with a symbol" do
+      -> { OpenSSL::Digest.new(:SHA1) }.should raise_error(TypeError, /wrong argument type Symbol/)
+    end
+
+    it "does not call #to_str on the argument" do
+      name = mock("digest name")
+      name.should_not_receive(:to_str)
+      -> { OpenSSL::Digest.new(name) }.should raise_error(TypeError, /wrong argument type/)
+    end
+  end
+
+  describe "can be called with a digest object" do
+    it "returns a SHA1 object" do
+      OpenSSL::Digest.new(OpenSSL::Digest::SHA1.new).name.should == "SHA1"
+    end
+
+    it "returns a SHA256 object" do
+      OpenSSL::Digest.new(OpenSSL::Digest::SHA256.new).name.should == "SHA256"
+    end
+
+    it "returns a SHA384 object" do
+      OpenSSL::Digest.new(OpenSSL::Digest::SHA384.new).name.should == "SHA384"
+    end
+
+    it "returns a SHA512 object" do
+      OpenSSL::Digest.new(OpenSSL::Digest::SHA512.new).name.should ==  "SHA512"
+    end
+
+    it "ignores the state of the digest object" do
+      sha1 = OpenSSL::Digest.new('sha1', SHA1Constants::Contents)
+      OpenSSL::Digest.new(sha1).digest.should == SHA1Constants::BlankDigest
+    end
+  end
+
+  it "cannot be called with a digest class" do
+    -> { OpenSSL::Digest.new(OpenSSL::Digest::SHA1) }.should raise_error(TypeError, /wrong argument type Class/)
+  end
+
+  context "when called without an initial String argument" do
+    it "returns a SHA1 digest" do
+      OpenSSL::Digest.new("sha1").digest.should == SHA1Constants::BlankDigest
+    end
+
+    it "returns a SHA256 digest" do
+      OpenSSL::Digest.new("sha256").digest.should == SHA256Constants::BlankDigest
+    end
+
+    it "returns a SHA384 digest" do
+      OpenSSL::Digest.new("sha384").digest.should == SHA384Constants::BlankDigest
+    end
+
+    it "returns a SHA512 digest" do
+      OpenSSL::Digest.new("sha512").digest.should == SHA512Constants::BlankDigest
+    end
+  end
+
+  context "when called with an initial String argument" do
+    it "returns a SHA1 digest of that argument" do
+      OpenSSL::Digest.new("sha1", SHA1Constants::Contents).digest.should == SHA1Constants::Digest
+    end
+
+    it "returns a SHA256 digest of that argument" do
+      OpenSSL::Digest.new("sha256", SHA256Constants::Contents).digest.should == SHA256Constants::Digest
+    end
+
+    it "returns a SHA384 digest of that argument" do
+      OpenSSL::Digest.new("sha384", SHA384Constants::Contents).digest.should == SHA384Constants::Digest
+    end
+
+    it "returns a SHA512 digest of that argument" do
+      OpenSSL::Digest.new("sha512", SHA512Constants::Contents).digest.should == SHA512Constants::Digest
+    end
+  end
+
+  context "can be called on subclasses" do
+    describe "can be called without an initial String argument on subclasses" do
+      it "returns a SHA1 digest" do
+        OpenSSL::Digest::SHA1.new.digest.should == SHA1Constants::BlankDigest
+      end
+
+      it "returns a SHA256 digest" do
+        OpenSSL::Digest::SHA256.new.digest.should == SHA256Constants::BlankDigest
+      end
+
+      it "returns a SHA384 digest" do
+        OpenSSL::Digest::SHA384.new.digest.should == SHA384Constants::BlankDigest
+      end
+
+      it "returns a SHA512 digest" do
+        OpenSSL::Digest::SHA512.new.digest.should == SHA512Constants::BlankDigest
+      end
+    end
+
+    describe "can be called with an initial String argument on subclasses" do
+      it "returns a SHA1 digest" do
+        OpenSSL::Digest::SHA1.new(SHA1Constants::Contents).digest.should == SHA1Constants::Digest
+      end
+
+      it "returns a SHA256 digest" do
+        OpenSSL::Digest::SHA256.new(SHA256Constants::Contents).digest.should == SHA256Constants::Digest
+      end
+
+      it "returns a SHA384 digest" do
+        OpenSSL::Digest::SHA384.new(SHA384Constants::Contents).digest.should == SHA384Constants::Digest
+      end
+
+      it "returns a SHA512 digest" do
+        OpenSSL::Digest::SHA512.new(SHA512Constants::Contents).digest.should == SHA512Constants::Digest
+      end
+    end
+  end
+end
diff --git a/library/openssl/digest/name_spec.rb b/library/openssl/digest/name_spec.rb
new file mode 100644
index 0000000000..b379f35c1c
--- /dev/null
+++ b/library/openssl/digest/name_spec.rb
@@ -0,0 +1,16 @@
+require_relative '../../../spec_helper'
+require 'openssl'
+
+describe "OpenSSL::Digest#name" do
+  it "returns the name of digest" do
+    OpenSSL::Digest.new('SHA1').name.should == 'SHA1'
+  end
+
+  it "converts the name to the internal representation of OpenSSL" do
+    OpenSSL::Digest.new('sha1').name.should == 'SHA1'
+  end
+
+  it "works on subclasses too" do
+    OpenSSL::Digest::SHA1.new.name.should == 'SHA1'
+  end
+end
diff --git a/library/openssl/digest/reset_spec.rb b/library/openssl/digest/reset_spec.rb
new file mode 100644
index 0000000000..c19bf46633
--- /dev/null
+++ b/library/openssl/digest/reset_spec.rb
@@ -0,0 +1,36 @@
+require_relative '../../../spec_helper'
+require_relative '../../../library/digest/sha1/shared/constants'
+require_relative '../../../library/digest/sha256/shared/constants'
+require_relative '../../../library/digest/sha384/shared/constants'
+require_relative '../../../library/digest/sha512/shared/constants'
+require 'openssl'
+
+describe "OpenSSL::Digest#reset" do
+  it "works for a SHA1 digest" do
+    digest = OpenSSL::Digest.new('sha1', SHA1Constants::Contents)
+    digest.reset
+    digest.update(SHA1Constants::Contents)
+    digest.digest.should == SHA1Constants::Digest
+  end
+
+  it "works for a SHA256 digest" do
+    digest = OpenSSL::Digest.new('sha256', SHA256Constants::Contents)
+    digest.reset
+    digest.update(SHA256Constants::Contents)
+    digest.digest.should == SHA256Constants::Digest
+  end
+
+  it "works for a SHA384 digest" do
+    digest = OpenSSL::Digest.new('sha384', SHA384Constants::Contents)
+    digest.reset
+    digest.update(SHA384Constants::Contents)
+    digest.digest.should == SHA384Constants::Digest
+  end
+
+  it "works for a SHA512 digest" do
+    digest = OpenSSL::Digest.new('sha512', SHA512Constants::Contents)
+    digest.reset
+    digest.update(SHA512Constants::Contents)
+    digest.digest.should == SHA512Constants::Digest
+  end
+end
diff --git a/library/openssl/digest/shared/update.rb b/library/openssl/digest/shared/update.rb
new file mode 100644
index 0000000000..e5ff9dcb16
--- /dev/null
+++ b/library/openssl/digest/shared/update.rb
@@ -0,0 +1,123 @@
+require_relative '../../../../library/digest/sha1/shared/constants'
+require_relative '../../../../library/digest/sha256/shared/constants'
+require_relative '../../../../library/digest/sha384/shared/constants'
+require_relative '../../../../library/digest/sha512/shared/constants'
+require 'openssl'
+
+describe :openssl_digest_update, shared: true do
+  context "when given input as a single string" do
+    it "returns a SHA1 digest" do
+      digest = OpenSSL::Digest.new('sha1')
+      digest.send(@method, SHA1Constants::Contents)
+      digest.digest.should == SHA1Constants::Digest
+    end
+
+    it "returns a SHA256 digest" do
+      digest = OpenSSL::Digest.new('sha256')
+      digest.send(@method, SHA256Constants::Contents)
+      digest.digest.should == SHA256Constants::Digest
+    end
+
+    it "returns a SHA384 digest" do
+      digest = OpenSSL::Digest.new('sha384')
+      digest.send(@method, SHA384Constants::Contents)
+      digest.digest.should == SHA384Constants::Digest
+    end
+
+    it "returns a SHA512 digest" do
+      digest = OpenSSL::Digest.new('sha512')
+      digest.send(@method, SHA512Constants::Contents)
+      digest.digest.should == SHA512Constants::Digest
+    end
+  end
+
+  context "when given input as multiple smaller substrings" do
+    it "returns a SHA1 digest" do
+      digest = OpenSSL::Digest.new('sha1')
+      SHA1Constants::Contents.each_char { |b| digest.send(@method, b) }
+      digest.digest.should == SHA1Constants::Digest
+    end
+
+    it "returns a SHA256 digest" do
+      digest = OpenSSL::Digest.new('sha256')
+      SHA256Constants::Contents.each_char { |b| digest.send(@method, b) }
+      digest.digest.should == SHA256Constants::Digest
+    end
+
+    it "returns a SHA384 digest" do
+      digest = OpenSSL::Digest.new('sha384')
+      SHA384Constants::Contents.each_char { |b| digest.send(@method, b) }
+      digest.digest.should == SHA384Constants::Digest
+    end
+
+    it "returns a SHA512 digest" do
+      digest = OpenSSL::Digest.new('sha512')
+      SHA512Constants::Contents.each_char { |b| digest.send(@method, b) }
+      digest.digest.should == SHA512Constants::Digest
+    end
+  end
+
+  context "when input is not a String and responds to #to_str" do
+    it "returns a SHA1 digest" do
+      str = mock('str')
+      str.should_receive(:to_str).and_return(SHA1Constants::Contents)
+      digest = OpenSSL::Digest.new('sha1')
+      digest.send(@method, str)
+      digest.digest.should == SHA1Constants::Digest
+    end
+
+    it "returns a SHA256 digest" do
+      str = mock('str')
+      str.should_receive(:to_str).and_return(SHA256Constants::Contents)
+      digest = OpenSSL::Digest.new('sha256')
+      digest.send(@method, str)
+      digest.digest.should == SHA256Constants::Digest
+    end
+
+    it "returns a SHA384 digest" do
+      str = mock('str')
+      str.should_receive(:to_str).and_return(SHA384Constants::Contents)
+      digest = OpenSSL::Digest.new('sha384')
+      digest.send(@method, str)
+      digest.digest.should == SHA384Constants::Digest
+    end
+
+    it "returns a SHA512 digest" do
+      str = mock('str')
+      str.should_receive(:to_str).and_return(SHA512Constants::Contents)
+      digest = OpenSSL::Digest.new('sha512')
+      digest.send(@method, str)
+      digest.digest.should == SHA512Constants::Digest
+    end
+  end
+
+  context "when input is not a String and does not respond to #to_str" do
+    it "raises a TypeError with SHA1" do
+      digest = OpenSSL::Digest.new('sha1')
+      -> {
+        digest.send(@method, Object.new)
+      }.should raise_error(TypeError, 'no implicit conversion of Object into String')
+    end
+
+    it "raises a TypeError with SHA256" do
+      digest = OpenSSL::Digest.new('sha256')
+      -> {
+        digest.send(@method, Object.new)
+      }.should raise_error(TypeError, 'no implicit conversion of Object into String')
+    end
+
+    it "raises a TypeError with SHA384" do
+      digest = OpenSSL::Digest.new('sha384')
+      -> {
+        digest.send(@method, Object.new)
+      }.should raise_error(TypeError, 'no implicit conversion of Object into String')
+    end
+
+    it "raises a TypeError with SHA512" do
+      digest = OpenSSL::Digest.new('sha512')
+      -> {
+        digest.send(@method, Object.new)
+      }.should raise_error(TypeError, 'no implicit conversion of Object into String')
+    end
+  end
+end
diff --git a/library/openssl/digest/update_spec.rb b/library/openssl/digest/update_spec.rb
new file mode 100644
index 0000000000..3a90b06c6b
--- /dev/null
+++ b/library/openssl/digest/update_spec.rb
@@ -0,0 +1,6 @@
+require_relative '../../../spec_helper'
+require_relative 'shared/update'
+
+describe "OpenSSL::Digest#update" do
+  it_behaves_like :openssl_digest_update, :update
+end