diff --git a/src/OpenSSL.jl b/src/OpenSSL.jl
index eb78254..30c64ca 100644
--- a/src/OpenSSL.jl
+++ b/src/OpenSSL.jl
@@ -30,7 +30,7 @@ export TLSv12ClientMethod, TLSv12ServerMethod,
     EvpEncNull, EvpBlowFishCBC, EvpBlowFishECB, EvpBlowFishCFB, EvpBlowFishOFB, EvpAES128CBC,
     EvpAES128ECB, EvpAES128CFB, EvpAES128OFB, EvpMDNull, EvpMD2, EvpMD5, EvpSHA1, EvpDSS1,
     encrypt_init, cipher, add_extension, add_extensions, decrypt_init, digest_init, digest_update, digest_final,
-    digest, random_bytes, rsa_generate_key, dsa_generate_key, add_entry, sign_certificate, sign_request, adjust,
+    digest, hmac, random_bytes, rsa_generate_key, dsa_generate_key, add_entry, sign_certificate, sign_request, adjust,
     add_cert, unpack, eof, isreadable, iswritable, bytesavailable, read, unsafe_write, connect,
     get_peer_certificate, free, HTTP2_ALPN, UPDATE_HTTP2_ALPN, version
 
@@ -1291,6 +1291,34 @@ function digest(evp_digest::EvpDigest, io::IO)
     return result
 end
 
+
+"""
+    Compute the hash-based message authentication code of the given data using a key and a hash function.
+"""
+function hmac(evp_digest::EvpDigest, in_data::AbstractVector{UInt8}, key::AbstractVector{UInt8})::Vector{UInt8}
+    out_data = Vector{UInt8}(undef, EVP_MAX_MD_SIZE)
+    out_length = Ref{UInt32}(0)
+    GC.@preserve key in_data out_data out_length begin
+        if ccall(
+            (:HMAC, libcrypto),
+            Ptr{Cchar},
+            (EvpDigest, Ptr{Cvoid}, Cint, Ptr{Cchar}, Csize_t, Ptr{Cchar}, Ptr{Cuint}),
+            evp_digest,
+            pointer(key), length(key),
+            pointer(in_data), length(in_data),
+            pointer(out_data), pointer_from_objref(out_length)) == C_NULL
+            throw(OpenSSLError())
+        end
+    end
+    resize!(out_data, out_length.x)
+    return out_data
+end
+
+hmac(evp_digest::EvpDigest, in_data::AbstractString, key::AbstractString)::Vector{UInt8} = hmac(evp_digest, codeunits(in_data), codeunits(key))
+hmac(evp_digest::EvpDigest, in_data::AbstractString, key::AbstractVector{UInt8})::Vector{UInt8} = hmac(evp_digest, codeunits(in_data), key)
+
+
+
 """
     RSA structure.
     The RSA structure consists of several BIGNUM components.
@@ -1454,7 +1482,7 @@ end
 
 """
     ec_generate_key(nid)
-    
+
 Generate EC key pair from a curve identifier. See ec_builtin_curves().
 
 """
@@ -1954,7 +1982,7 @@ mutable struct EvpPKey
 
     function EvpPKey(ec::EC)::EvpPKey
         evp_pkey = EvpPKey()
-    
+
         if ccall(
             (:EVP_PKEY_assign, libcrypto),
             Cint, (EvpPKey, Cint, EC),
@@ -1963,7 +1991,7 @@ mutable struct EvpPKey
             ec) != 1
             throw(OpenSSLError())
         end
-    
+
         ec.ec = C_NULL
         return evp_pkey
     end
diff --git a/test/runtests.jl b/test/runtests.jl
index 5be468a..c7fdf93 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -277,6 +277,17 @@ end
     @test bytes2hex(digest(OpenSSL.EvpRIPEMD160(), IOBuffer("abc"))) == "8eb208f7e05d987a9b044a8e98c6b087f15a0bfc"
 end
 
+@testset "HMAC" begin
+	# echo -n "Hello world" | openssl dgst -sha256 -mac hmac -macopt hexkey:01020304
+	@test bytes2hex(hmac(OpenSSL.EvpSHA256(), "Hello world", hex2bytes("01020304"))) == "760e94f3d42452f372885f22d3ed5915ffa5a7d6ddf38716331f9c2786f21e5a"
+
+	# echo -n "Hello world" | openssl dgst -sha512 -hmac "Σλ"
+	@test bytes2hex(hmac(OpenSSL.EvpSHA512(), "Hello world", "Σλ")) == "dfe48de81d0f5f8976d20e10c6fa2f82ff3cc28ae5060b396f70e26d45563a4cfa446d53d5fbea377018b54dac1ec368c979fb2b4a99f642cb0a2d8422c3bfa6"
+
+	# echo -n "Hello world" | openssl dgst -sha256 -hmac ""
+	@test bytes2hex(hmac(OpenSSL.EvpSHA256(), [0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x20, 0x77, 0x6f, 0x72, 0x6c, 0x64], b"")) == "c50d316a00f927059322a898ea2fa7321fdb4d32eb749656ea7ba7775a870dc0"
+end
+
 @testset "SelfSignedCertificate" begin
     x509_certificate = X509Certificate()
 
@@ -675,8 +686,8 @@ end
 
 @testset "CACertsLoading" begin
     certs_dir = joinpath(@__DIR__, "certs")
-    certs_path = joinpath(certs_dir, "ca-certificates.crt") 
-    
+    certs_path = joinpath(certs_dir, "ca-certificates.crt")
+
     ssl_method = OpenSSL.TLSClientMethod()
     ctx = OpenSSL.SSLContext(ssl_method, certs_path)
     @test typeof(ctx) == OpenSSL.SSLContext