diff --git a/authentication.go b/authentication.go
index f8ead404..b515adf6 100644
--- a/authentication.go
+++ b/authentication.go
@@ -7,9 +7,7 @@ import (
 	"crypto/sha1"
 	"crypto/sha256"
 	"encoding/base64"
-	"errors"
 	"io"
-	"math/big"
 )
 
 // GenerateDigestSignature will generate a signature of the given data protocol 1.3
@@ -24,7 +22,7 @@ func GenerateDigestSignature(priv *rsa.PrivateKey, string_to_sign string) (sig [
 
 // GenerateSignature will generate a signature ( sign ) the given data
 func GenerateSignature(priv *rsa.PrivateKey, data string) (enc []byte, err error) {
-	sig, err := privateEncrypt(priv, []byte(data))
+	sig, err := rsa.SignPKCS1v15(rand.Reader, priv, 0, []byte(data))
 	if err != nil {
 		return nil, err
 	}
@@ -32,68 +30,6 @@ func GenerateSignature(priv *rsa.PrivateKey, data string) (enc []byte, err error
 	return sig, nil
 }
 
-// privateEncrypt implements OpenSSL's RSA_private_encrypt function
-func privateEncrypt(key *rsa.PrivateKey, data []byte) (enc []byte, err error) {
-	k := (key.N.BitLen() + 7) / 8
-	tLen := len(data)
-
-	// rfc2313, section 8:
-	// The length of the data D shall not be more than k-11 octets
-	if tLen > k-11 {
-		err = errors.New("Data too long")
-		return
-	}
-	em := make([]byte, k)
-	em[1] = 1
-	for i := 2; i < k-tLen-1; i++ {
-		em[i] = 0xff
-	}
-	copy(em[k-tLen:k], data)
-	c := new(big.Int).SetBytes(em)
-	if c.Cmp(key.N) > 0 {
-		err = nil
-		return
-	}
-	var m *big.Int
-	var ir *big.Int
-	if key.Precomputed.Dp == nil {
-		m = new(big.Int).Exp(c, key.D, key.N)
-	} else {
-		// We have the precalculated values needed for the CRT.
-		m = new(big.Int).Exp(c, key.Precomputed.Dp, key.Primes[0])
-		m2 := new(big.Int).Exp(c, key.Precomputed.Dq, key.Primes[1])
-		m.Sub(m, m2)
-		if m.Sign() < 0 {
-			m.Add(m, key.Primes[0])
-		}
-		m.Mul(m, key.Precomputed.Qinv)
-		m.Mod(m, key.Primes[0])
-		m.Mul(m, key.Primes[1])
-		m.Add(m, m2)
-
-		for i, values := range key.Precomputed.CRTValues {
-			prime := key.Primes[2+i]
-			m2.Exp(c, values.Exp, prime)
-			m2.Sub(m2, m)
-			m2.Mul(m2, values.Coeff)
-			m2.Mod(m2, prime)
-			if m2.Sign() < 0 {
-				m2.Add(m2, prime)
-			}
-			m2.Mul(m2, values.R)
-			m.Add(m, m2)
-		}
-	}
-
-	if ir != nil {
-		// Unblind.
-		m.Mul(m, ir)
-		m.Mod(m, key.N)
-	}
-	enc = m.Bytes()
-	return
-}
-
 // HashStr returns the base64 encoded SHA1 sum of the toHash string
 func HashStr(toHash string) string {
 	h := sha1.New()
diff --git a/authentication_test.go b/authentication_test.go
index c5055864..eaa66b5a 100644
--- a/authentication_test.go
+++ b/authentication_test.go
@@ -1,13 +1,24 @@
 package chef
 
 import (
+	"crypto/rsa"
+	"encoding/base64"
 	"testing"
+
+	"github.com/stretchr/testify/assert"
 )
 
+type privateKey struct {
+	name string
+	key  *rsa.PrivateKey
+}
+
 const (
 	teststr     = "Hash this string"
 	testsha1    = "hdBcDGYOo5/Q4k2DojVVP1ANs3U="
 	testsha256  = "HKxj85/WjYxTHye4B2EPs9UPD8PxhplXZ/tjFucgCj4="
+	signature10 = "Z6mh9AcCOylVV4mR2MdgQ+FxriOjFipbcowQkDNIOT9o2pVxdzqC4mstZfF430wAEd+HLPXldJafQINmWpHzG2tDd+ms3WQBIq2/kCLmSljP7DHulOsJVeznXtcOwlg6KP4xTK4CYZoh8YuqW3VbdXyGwgx8iOKYac7EBFoKHxu2B4ggDq6NhDvYTA7eNLdXhaotEh6oNkiTByWndUki0boz82R6jMBtMw0ww4ENhZ6Mt3KeC95cFpv5dhmLXWGYVCbCnhWHsUuQlW5Ii1897muSWa+nlQBK6EBiqL8GD/3X8hHta9YLt8zM7W0hqo4NmFKie6mCaaX51Z6ExzUEgw=="
+	signature13 = "EuuCVnnbDBah5WiTy9cM1OwhPp+rEQl6L60E9dpYCEcvCMdvs5G6fVuW9wyo7wHlLETMmbltNccdmlByACWKobFi98oH/aYTz6Z7qRxiAJX8Z/b6C6K1c5mxKeJguOt86SGKd6aqQ4O20bXncKJ6u9HxfALphYHIJHegXC414bGbnWbDowI9ZQpNWZ/10bqyoOIiGAOJbzmU2jn6+2eey78sTbKYmddNJzaVzJAq7dtHvGG0yE1h0Y3lCN3mWP9rVu2tVClXKhpOJ1CQGY7t3gVrBtVVvgdQNBW5rhGWDD6BkwRigGiwBczSVk8a1oTiAMRHPXurrEr+c7ArItrUvA=="
 	privateKeyG = `
 -----BEGIN RSA PRIVATE KEY-----
 MIIEpAIBAAKCAQEAx12nDxxOwSPHRSJEDz67a0folBqElzlu2oGMiUTS+dqtj3FU
@@ -36,32 +47,77 @@ rlXw1QKBgQDBOyUJKQOgDE2u9EHybhCIbfowyIE22qn9a3WjQgfxFJ+aAL9Bg124
 fJIEzz43fJ91fe5lTOgyMF5TtU5ClAOPGtlWnXU0e5j3L4LjbcqzEbeyxvP3sn1z
 dYkX7NdNQ5E6tcJZuJCGq0HxIAQeKPf3x9DRKzMnLply6BEzyuAC4g==
 -----END RSA PRIVATE KEY-----
+`
+	privateKey8 = `
+-----BEGIN PRIVATE KEY-----
+MIIEvgIBADANBgkqhkiG9w0BAQEFAASCBKgwggSkAgEAAoIBAQDHXacPHE7BI8dF
+IkQPPrtrR+iUGoSXOW7agYyJRNL52q2PcVSHmUlzUyNymtFXFwNXCGxJKj33jxcS
+STf0h1uVQIuiG5yo0zM6chx1mfzNuU3sKelbTdTBEzSJZfUe7Aeca+bo8p6ooaqm
+XIhdg7SqUNYLML5VrEVPA5STfUx84clCfjJ9Ot+4TuHcVMSUsG7TrlIWnd08gIgS
+ZYKX0Np2fFudnwBLFhD3EbuGZl24OCM1bmXfHr8QWSnKb7/8PoBtYNxUnWi8Kwkv
+cJ8f81kLd6R4n9oR4vE/+9oJIfVVgLlWxgrlCDtIhro22Hf5FnPWFg6gEm6UTPCW
+POfChlhFAgMBAAECggEAM9CiX6oCye3Ll6s9Nx0dxtcsmnl95nPV3NJ4vSB3GNr9
+6t8QkiGD1oZQGzQjnlfr1U3qHuXsrw+wdl8zPMmFQvhAkkRM5g/mK5WG0gXQj4NO
+vkdyT/mdhwS/zcoC+CNuIvhkTjzogXlrCcvY4T0e0nkp+ESV41xfsxaCIgcZvwbW
+MKq7+0fQYjxnhw2BStcxtzMbB9s3/lZzTOgO2l7RN5z8V3QMsXBGIC6F5qQ+OVVZ
+vsAYwNfhPLMJd8ylLW6XaOTqcYWTvu5CjMU9BRrAJGn6ZVLip5yCr9ap9NllsGVb
+YvXz+Slp++zEbyQns5ES2tvRKWhk0UcRzZDvQZuAoQKBgQDpz946sjdSi6vWAp7M
+QEWYUoUfphL81k2lxIbk9yioXoBUnBeDnvhDLpFq0Ljt73Zt7ZNPU7KmWe2Pi+Rn
+dES/zXJ/P+25ea0bQDKUftERvG5vECBiZRPXzBQAvizdNJPYCUrhHb0rAFp3BQAl
+44s1b5FzjGG3WBqWypBFvilTOQKBgQDaSPa9SEoAHtAUI9JPjn/mr4ABO63xZ4ec
+j63VRqJmgrjUmt7xPCVipSBwnXpDQfoohsmOURkC7QiwnGNDGQPigmC/yfk8Vd1z
+XgdxJDnXYWaAIY3C0Nj8BPtJA/eQ6PRHJ2A3Ta65Fv/nk0nTsGH7JNA0YD4zlJKd
+TJpE8gAxbQKBgGBVTuCsMPMHrQL+DWNmT8ZUqZjCmiwmN9PGxzVrSAsm9ITn0yBd
+zTgQ5cU2vhr6gLcGHZ2fhInZn3F3V+HwG6tTAIvBUTcMFPCXYL+iCI3gLzf/Uvh3
+YNeWs98ie+WgFhH6silSUXB4Ms2697akq+SWVT1gZ5pc6IecahjyIqCxAoGBANko
+w4e1liEehmWy6XTKUIYATPltFPRXyftAmXDXb5NKM3UXifo2mv7TRj2i/VJSHfwZ
+dAWIurhFdmK1gq7rAQlkKbpDxhd3WPOANSkjIAQc2ytXtj99JJE8p32RW8anavYq
+vzblqpBqyDXrOwRFsoR2sEebA+auxVmGLueuVfDVAoGBAME7JQkpA6AMTa70QfJu
+EIht+jDIgTbaqf1rdaNCB/EUn5oAv0GDXbh8kgTPPjd8n3V97mVM6DIwXlO1TkKU
+A48a2VaddTR7mPcvguNtyrMRt7LG8/eyfXN1iRfs101DkTq1wlm4kIarQfEgBB4o
+9/fH0NErMycumXLoETPK4ALi
+-----END PRIVATE KEY-----
 `
 )
 
 var testblock = "Stuff and nonsense to encode  "
 
-func TestGenerateDigestSignature(t *testing.T) {
-	pk, _ := PrivateKeyFromString([]byte(privateKeyG))
-	_, err := GenerateDigestSignature(pk, teststr)
+func getPrivateKeys() ([]privateKey, error) {
+	pkcs1, err := PrivateKeyFromString([]byte(privateKeyG))
+	if err != nil {
+		return nil, err
+	}
+	pkcs8, err := PrivateKeyFromString([]byte(privateKey8))
 	if err != nil {
-		t.Error("Error generating signature", err)
+		return nil, err
 	}
+	return []privateKey{
+		{"pkcs#1", pkcs1},
+		{"pkcs#8", pkcs8},
+	}, nil
 }
 
-func TestGenerateSignature(t *testing.T) {
-	pk, _ := PrivateKeyFromString([]byte(privateKeyG))
-	_, err := GenerateSignature(pk, teststr)
-	if err != nil {
-		t.Error("Error generating signature", err)
+func TestGenerateDigestSignature(t *testing.T) {
+	pks, _ := getPrivateKeys()
+	for _, pk := range pks {
+		signed, err := GenerateDigestSignature(pk.key, teststr)
+		if err != nil {
+			t.Error("Error generating signature", pk.name, err)
+		}
+		assert.Equalf(t, signature13, base64.StdEncoding.EncodeToString(signed),
+			"Signature doesn't match. Version=%+v, KeyType=%+v", "1.0", pk.name)
 	}
 }
 
-func TestPrivateEncrypt(t *testing.T) {
-	pk, _ := PrivateKeyFromString([]byte(privateKeyG))
-	_, err := privateEncrypt(pk, []byte(teststr))
-	if err != nil {
-		t.Error("Error encrypting", err)
+func TestGenerateSignature(t *testing.T) {
+	pks, _ := getPrivateKeys()
+	for _, pk := range pks {
+		signed, err := GenerateSignature(pk.key, teststr)
+		if err != nil {
+			t.Error("Error generating signature", pk.name, err)
+		}
+		assert.Equalf(t, signature10, base64.StdEncoding.EncodeToString(signed),
+			"Signature doesn't match. Version=%+v, KeyType=%+v", "1.3", pk.name)
 	}
 }