diff --git a/cmd/config/identity/openid/jwt.go b/cmd/config/identity/openid/jwt.go
index c11fcdfe2..d478ab1b5 100644
--- a/cmd/config/identity/openid/jwt.go
+++ b/cmd/config/identity/openid/jwt.go
@@ -28,6 +28,7 @@ import (
 
 	jwtgo "github.com/dgrijalva/jwt-go"
 	"github.com/minio/minio/cmd/config"
+	"github.com/minio/minio/pkg/auth"
 	"github.com/minio/minio/pkg/env"
 	xnet "github.com/minio/minio/pkg/net"
 )
@@ -107,36 +108,19 @@ type JWT struct {
 	Config
 }
 
-func expToInt64(expI interface{}) (expAt int64, err error) {
-	switch exp := expI.(type) {
-	case float64:
-		expAt = int64(exp)
-	case int64:
-		expAt = exp
-	case json.Number:
-		expAt, err = exp.Int64()
-		if err != nil {
-			return 0, err
-		}
-	default:
-		return 0, ErrInvalidDuration
-	}
-	return expAt, nil
-}
-
 // GetDefaultExpiration - returns the expiration seconds expected.
 func GetDefaultExpiration(dsecs string) (time.Duration, error) {
 	defaultExpiryDuration := time.Duration(60) * time.Minute // Defaults to 1hr.
 	if dsecs != "" {
 		expirySecs, err := strconv.ParseInt(dsecs, 10, 64)
 		if err != nil {
-			return 0, ErrInvalidDuration
+			return 0, auth.ErrInvalidDuration
 		}
 		// The duration, in seconds, of the role session.
 		// The value can range from 900 seconds (15 minutes)
 		// to 12 hours.
 		if expirySecs < 900 || expirySecs > 43200 {
-			return 0, ErrInvalidDuration
+			return 0, auth.ErrInvalidDuration
 		}
 
 		defaultExpiryDuration = time.Duration(expirySecs) * time.Second
@@ -144,6 +128,39 @@ func GetDefaultExpiration(dsecs string) (time.Duration, error) {
 	return defaultExpiryDuration, nil
 }
 
+func updateClaimsExpiry(dsecs string, claims map[string]interface{}) error {
+	expStr := claims["exp"]
+	if expStr == "" {
+		return ErrTokenExpired
+	}
+
+	// No custom duration requested, the claims can be used as is.
+	if dsecs == "" {
+		return nil
+	}
+
+	expAt, err := auth.ExpToInt64(expStr)
+	if err != nil {
+		return err
+	}
+
+	defaultExpiryDuration, err := GetDefaultExpiration(dsecs)
+	if err != nil {
+		return err
+	}
+
+	// Verify if JWT expiry is lesser than default expiry duration,
+	// if that is the case then set the default expiration to be
+	// from the JWT expiry claim.
+	if time.Unix(expAt, 0).UTC().Sub(time.Now().UTC()) < defaultExpiryDuration {
+		defaultExpiryDuration = time.Unix(expAt, 0).UTC().Sub(time.Now().UTC())
+	} // else honor the specified expiry duration.
+
+	expiry := time.Now().UTC().Add(defaultExpiryDuration).Unix()
+	claims["exp"] = strconv.FormatInt(expiry, 10) // update with new expiry.
+	return nil
+}
+
 // Validate - validates the access token.
 func (p *JWT) Validate(token, dsecs string) (map[string]interface{}, error) {
 	jp := new(jwtgo.Parser)
@@ -173,25 +190,10 @@ func (p *JWT) Validate(token, dsecs string) (map[string]interface{}, error) {
 		return nil, ErrTokenExpired
 	}
 
-	expAt, err := expToInt64(claims["exp"])
-	if err != nil {
+	if err = updateClaimsExpiry(dsecs, claims); err != nil {
 		return nil, err
 	}
 
-	defaultExpiryDuration, err := GetDefaultExpiration(dsecs)
-	if err != nil {
-		return nil, err
-	}
-
-	if time.Unix(expAt, 0).UTC().Sub(time.Now().UTC()) < defaultExpiryDuration {
-		defaultExpiryDuration = time.Unix(expAt, 0).UTC().Sub(time.Now().UTC())
-	}
-
-	expiry := time.Now().UTC().Add(defaultExpiryDuration).Unix()
-	if expAt < expiry {
-		claims["exp"] = strconv.FormatInt(expAt, 64)
-	}
-
 	return claims, nil
 
 }
diff --git a/cmd/config/identity/openid/jwt_test.go b/cmd/config/identity/openid/jwt_test.go
index 67a825363..1a08fe042 100644
--- a/cmd/config/identity/openid/jwt_test.go
+++ b/cmd/config/identity/openid/jwt_test.go
@@ -1,5 +1,5 @@
 /*
- * MinIO Cloud Storage, (C) 2018 MinIO, Inc.
+ * MinIO Cloud Storage, (C) 2018-2019 MinIO, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -26,6 +26,42 @@ import (
 	xnet "github.com/minio/minio/pkg/net"
 )
 
+func TestUpdateClaimsExpiry(t *testing.T) {
+	testCases := []struct {
+		exp             interface{}
+		dsecs           string
+		expectedFailure bool
+	}{
+		{"", "", true},
+		{"-1", "0", true},
+		{"-1", "900", true},
+		{"1574812326", "900", false},
+		{1574812326, "900", false},
+		{int64(1574812326), "900", false},
+		{int(1574812326), "900", false},
+		{uint(1574812326), "900", false},
+		{uint64(1574812326), "900", false},
+		{json.Number("1574812326"), "900", false},
+		{1574812326.000, "900", false},
+		{time.Duration(3) * time.Minute, "900", false},
+	}
+
+	for _, testCase := range testCases {
+		testCase := testCase
+		t.Run("", func(t *testing.T) {
+			claims := map[string]interface{}{}
+			claims["exp"] = testCase.exp
+			err := updateClaimsExpiry(testCase.dsecs, claims)
+			if err != nil && !testCase.expectedFailure {
+				t.Errorf("Expected success, got failure %s", err)
+			}
+			if err == nil && testCase.expectedFailure {
+				t.Error("Expected failure, got success")
+			}
+		})
+	}
+}
+
 func TestJWT(t *testing.T) {
 	const jsonkey = `{"keys":
        [
diff --git a/cmd/config/identity/openid/validators.go b/cmd/config/identity/openid/validators.go
index 57a9911d0..2a0682c95 100644
--- a/cmd/config/identity/openid/validators.go
+++ b/cmd/config/identity/openid/validators.go
@@ -38,8 +38,7 @@ type Validator interface {
 
 // ErrTokenExpired - error token expired
 var (
-	ErrTokenExpired    = errors.New("token expired")
-	ErrInvalidDuration = errors.New("duration higher than token expiry")
+	ErrTokenExpired = errors.New("token expired")
 )
 
 // Validators - holds list of providers indexed by provider id.
diff --git a/cmd/sts-handlers.go b/cmd/sts-handlers.go
index 35879b414..1134efd96 100644
--- a/cmd/sts-handlers.go
+++ b/cmd/sts-handlers.go
@@ -36,7 +36,15 @@ import (
 
 const (
 	// STS API version.
-	stsAPIVersion = "2011-06-15"
+	stsAPIVersion       = "2011-06-15"
+	stsVersion          = "Version"
+	stsAction           = "Action"
+	stsPolicy           = "Policy"
+	stsToken            = "Token"
+	stsWebIdentityToken = "WebIdentityToken"
+	stsDurationSeconds  = "DurationSeconds"
+	stsLDAPUsername     = "LDAPUsername"
+	stsLDAPPassword     = "LDAPPassword"
 
 	// STS API action constants
 	clientGrants = "AssumeRoleWithClientGrants"
@@ -46,6 +54,10 @@ const (
 
 	stsRequestBodyLimit = 10 * (1 << 20) // 10 MiB
 
+	// JWT claim keys
+	expClaim = "exp"
+	subClaim = "sub"
+
 	// LDAP claim keys
 	ldapUser   = "ldapUser"
 	ldapGroups = "ldapGroups"
@@ -71,30 +83,30 @@ func registerSTSRouter(router *mux.Router) {
 	}).HandlerFunc(httpTraceAll(sts.AssumeRole))
 
 	// Assume roles with JWT handler, handles both ClientGrants and WebIdentity.
-	stsRouter.Methods("POST").MatcherFunc(func(r *http.Request, rm *mux.RouteMatch) bool {
+	stsRouter.Methods(http.MethodPost).MatcherFunc(func(r *http.Request, rm *mux.RouteMatch) bool {
 		ctypeOk := wildcard.MatchSimple("application/x-www-form-urlencoded*", r.Header.Get(xhttp.ContentType))
 		noQueries := len(r.URL.Query()) == 0
 		return ctypeOk && noQueries
 	}).HandlerFunc(httpTraceAll(sts.AssumeRoleWithJWT))
 
 	// AssumeRoleWithClientGrants
-	stsRouter.Methods("POST").HandlerFunc(httpTraceAll(sts.AssumeRoleWithClientGrants)).
-		Queries("Action", clientGrants).
-		Queries("Version", stsAPIVersion).
-		Queries("Token", "{Token:.*}")
+	stsRouter.Methods(http.MethodPost).HandlerFunc(httpTraceAll(sts.AssumeRoleWithClientGrants)).
+		Queries(stsAction, clientGrants).
+		Queries(stsVersion, stsAPIVersion).
+		Queries(stsToken, "{Token:.*}")
 
 	// AssumeRoleWithWebIdentity
-	stsRouter.Methods("POST").HandlerFunc(httpTraceAll(sts.AssumeRoleWithWebIdentity)).
-		Queries("Action", webIdentity).
-		Queries("Version", stsAPIVersion).
-		Queries("WebIdentityToken", "{Token:.*}")
+	stsRouter.Methods(http.MethodPost).HandlerFunc(httpTraceAll(sts.AssumeRoleWithWebIdentity)).
+		Queries(stsAction, webIdentity).
+		Queries(stsVersion, stsAPIVersion).
+		Queries(stsWebIdentityToken, "{Token:.*}")
 
 	// AssumeRoleWithLDAPIdentity
-	stsRouter.Methods("POST").HandlerFunc(httpTraceAll(sts.AssumeRoleWithLDAPIdentity)).
-		Queries("Action", ldapIdentity).
-		Queries("Version", stsAPIVersion).
-		Queries("LDAPUsername", "{LDAPUsername:.*}").
-		Queries("LDAPPassword", "{LDAPPassword:.*}")
+	stsRouter.Methods(http.MethodPost).HandlerFunc(httpTraceAll(sts.AssumeRoleWithLDAPIdentity)).
+		Queries(stsAction, ldapIdentity).
+		Queries(stsVersion, stsAPIVersion).
+		Queries(stsLDAPUsername, "{LDAPUsername:.*}").
+		Queries(stsLDAPPassword, "{LDAPPassword:.*}")
 }
 
 func checkAssumeRoleAuth(ctx context.Context, r *http.Request) (user auth.Credentials, stsErr STSErrorCode) {
@@ -141,12 +153,12 @@ func (sts *stsAPIHandlers) AssumeRole(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	if r.Form.Get("Version") != stsAPIVersion {
-		writeSTSErrorResponse(ctx, w, ErrSTSMissingParameter, fmt.Errorf("Invalid STS API version %s, expecting %s", r.Form.Get("Version"), stsAPIVersion))
+	if r.Form.Get(stsVersion) != stsAPIVersion {
+		writeSTSErrorResponse(ctx, w, ErrSTSMissingParameter, fmt.Errorf("Invalid STS API version %s, expecting %s", r.Form.Get(stsVersion), stsAPIVersion))
 		return
 	}
 
-	action := r.Form.Get("Action")
+	action := r.Form.Get(stsAction)
 	switch action {
 	case assumeRole:
 	default:
@@ -157,7 +169,7 @@ func (sts *stsAPIHandlers) AssumeRole(w http.ResponseWriter, r *http.Request) {
 	ctx = newContext(r, w, action)
 	defer logger.AuditLog(w, r, action, nil)
 
-	sessionPolicyStr := r.Form.Get("Policy")
+	sessionPolicyStr := r.Form.Get(stsPolicy)
 	// https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRole.html
 	// The plain text that you use for both inline and managed session
 	// policies shouldn't exceed 2048 characters.
@@ -182,7 +194,7 @@ func (sts *stsAPIHandlers) AssumeRole(w http.ResponseWriter, r *http.Request) {
 
 	var err error
 	m := make(map[string]interface{})
-	m["exp"], err = openid.GetDefaultExpiration(r.Form.Get("DurationSeconds"))
+	m[expClaim], err = openid.GetDefaultExpiration(r.Form.Get(stsDurationSeconds))
 	if err != nil {
 		writeSTSErrorResponse(ctx, w, ErrSTSInvalidParameterValue, err)
 		return
@@ -248,12 +260,12 @@ func (sts *stsAPIHandlers) AssumeRoleWithJWT(w http.ResponseWriter, r *http.Requ
 		return
 	}
 
-	if r.Form.Get("Version") != stsAPIVersion {
+	if r.Form.Get(stsVersion) != stsAPIVersion {
 		writeSTSErrorResponse(ctx, w, ErrSTSMissingParameter, fmt.Errorf("Invalid STS API version %s, expecting %s", r.Form.Get("Version"), stsAPIVersion))
 		return
 	}
 
-	action := r.Form.Get("Action")
+	action := r.Form.Get(stsAction)
 	switch action {
 	case clientGrants, webIdentity:
 	default:
@@ -275,12 +287,12 @@ func (sts *stsAPIHandlers) AssumeRoleWithJWT(w http.ResponseWriter, r *http.Requ
 		return
 	}
 
-	token := r.Form.Get("Token")
+	token := r.Form.Get(stsToken)
 	if token == "" {
-		token = r.Form.Get("WebIdentityToken")
+		token = r.Form.Get(stsWebIdentityToken)
 	}
 
-	m, err := v.Validate(token, r.Form.Get("DurationSeconds"))
+	m, err := v.Validate(token, r.Form.Get(stsDurationSeconds))
 	if err != nil {
 		switch err {
 		case openid.ErrTokenExpired:
@@ -291,7 +303,7 @@ func (sts *stsAPIHandlers) AssumeRoleWithJWT(w http.ResponseWriter, r *http.Requ
 				writeSTSErrorResponse(ctx, w, ErrSTSWebIdentityExpiredToken, err)
 			}
 			return
-		case openid.ErrInvalidDuration:
+		case auth.ErrInvalidDuration:
 			writeSTSErrorResponse(ctx, w, ErrSTSInvalidParameterValue, err)
 			return
 		}
@@ -299,7 +311,7 @@ func (sts *stsAPIHandlers) AssumeRoleWithJWT(w http.ResponseWriter, r *http.Requ
 		return
 	}
 
-	sessionPolicyStr := r.Form.Get("Policy")
+	sessionPolicyStr := r.Form.Get(stsPolicy)
 	// https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRoleWithWebIdentity.html
 	// The plain text that you use for both inline and managed session
 	// policies shouldn't exceed 2048 characters.
@@ -343,7 +355,7 @@ func (sts *stsAPIHandlers) AssumeRoleWithJWT(w http.ResponseWriter, r *http.Requ
 	}
 
 	var subFromToken string
-	if v, ok := m["sub"]; ok {
+	if v, ok := m[subClaim]; ok {
 		subFromToken, _ = v.(string)
 	}
 
@@ -415,12 +427,12 @@ func (sts *stsAPIHandlers) AssumeRoleWithLDAPIdentity(w http.ResponseWriter, r *
 		return
 	}
 
-	if r.Form.Get("Version") != stsAPIVersion {
+	if r.Form.Get(stsVersion) != stsAPIVersion {
 		writeSTSErrorResponse(ctx, w, ErrSTSMissingParameter, fmt.Errorf("Invalid STS API version %s, expecting %s", r.Form.Get("Version"), stsAPIVersion))
 		return
 	}
 
-	action := r.Form.Get("Action")
+	action := r.Form.Get(stsAction)
 	switch action {
 	case ldapIdentity:
 	default:
@@ -431,15 +443,15 @@ func (sts *stsAPIHandlers) AssumeRoleWithLDAPIdentity(w http.ResponseWriter, r *
 	ctx = newContext(r, w, action)
 	defer logger.AuditLog(w, r, action, nil)
 
-	ldapUsername := r.Form.Get("LDAPUsername")
-	ldapPassword := r.Form.Get("LDAPPassword")
+	ldapUsername := r.Form.Get(stsLDAPUsername)
+	ldapPassword := r.Form.Get(stsLDAPPassword)
 
 	if ldapUsername == "" || ldapPassword == "" {
 		writeSTSErrorResponse(ctx, w, ErrSTSMissingParameter, fmt.Errorf("LDAPUsername and LDAPPassword cannot be empty"))
 		return
 	}
 
-	sessionPolicyStr := r.Form.Get("Policy")
+	sessionPolicyStr := r.Form.Get(stsPolicy)
 	// https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRole.html
 	// The plain text that you use for both inline and managed session
 	// policies shouldn't exceed 2048 characters.
@@ -516,9 +528,9 @@ func (sts *stsAPIHandlers) AssumeRoleWithLDAPIdentity(w http.ResponseWriter, r *
 	}
 	expiryDur := globalLDAPConfig.GetExpiryDuration()
 	m := map[string]interface{}{
-		"exp":        UTCNow().Add(expiryDur).Unix(),
-		"ldapUser":   ldapUsername,
-		"ldapGroups": groups,
+		expClaim:   UTCNow().Add(expiryDur).Unix(),
+		ldapUser:   ldapUsername,
+		ldapGroups: groups,
 	}
 
 	if len(sessionPolicyStr) > 0 {
diff --git a/docs/sts/assume-role.md b/docs/sts/assume-role.md
index 0a3f0f51a..0e24aa0d9 100644
--- a/docs/sts/assume-role.md
+++ b/docs/sts/assume-role.md
@@ -10,7 +10,7 @@
     - [Policy](#policy)
     - [Response Elements](#response-elements)
     - [Errors](#errors)
-- [Sample Request](#sample-request)
+- [Sample `POST` Request](#sample-post-request)
 - [Sample Response](#sample-response)
 - [Testing](#testing)
 
@@ -60,7 +60,7 @@ XML response for this API is similar to [AWS STS AssumeRole](https://docs.aws.am
 ### Errors
 XML error response for this API is similar to [AWS STS AssumeRole](https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRole.html#API_AssumeRole_Errors)
 
-## Sample Request
+## Sample `POST` Request
 ```
 http://minio:9000/?Action=AssumeRole&DurationSeconds=3600&Version=2011-06-15&Policy={"Version":"2012-10-17","Statement":[{"Sid":"Stmt1","Effect":"Allow","Action":"s3:*","Resource":"arn:aws:s3:::*"}]}&AUTHPARAMS
 ```
diff --git a/docs/sts/client-grants.md b/docs/sts/client-grants.md
index 3cfa4b6ae..cddb66cd1 100644
--- a/docs/sts/client-grants.md
+++ b/docs/sts/client-grants.md
@@ -10,7 +10,7 @@
     - [Policy](#policy)
     - [Response Elements](#response-elements)
     - [Errors](#errors)
-- [Sample Request](#sample-request)
+- [Sample `POST` Request](#sample-post-request)
 - [Sample Response](#sample-response)
 - [Testing](#testing)
 
@@ -64,7 +64,7 @@ XML response for this API is similar to [AWS STS AssumeRoleWithWebIdentity](http
 ### Errors
 XML error response for this API is similar to [AWS STS AssumeRoleWithWebIdentity](https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRoleWithWebIdentity.html#API_AssumeRoleWithWebIdentity_Errors)
 
-## Sample Request
+## Sample `POST` Request
 ```
 http://minio.cluster:9000?Action=AssumeRoleWithClientGrants&DurationSeconds=3600&Token=eyJ4NXQiOiJOVEF4Wm1NeE5ETXlaRGczTVRVMVpHTTBNekV6T0RKaFpXSTRORE5sWkRVMU9HRmtOakZpTVEiLCJraWQiOiJOVEF4Wm1NeE5ETXlaRGczTVRVMVpHTTBNekV6T0RKaFpXSTRORE5sWkRVMU9HRmtOakZpTVEiLCJhbGciOiJSUzI1NiJ9.eyJhdWQiOiJQb0VnWFA2dVZPNDVJc0VOUm5nRFhqNUF1NVlhIiwiYXpwIjoiUG9FZ1hQNnVWTzQ1SXNFTlJuZ0RYajVBdTVZYSIsImlzcyI6Imh0dHBzOlwvXC9sb2NhbGhvc3Q6OTQ0M1wvb2F1dGgyXC90b2tlbiIsImV4cCI6MTU0MTgwOTU4MiwiaWF0IjoxNTQxODA1OTgyLCJqdGkiOiI2Y2YyMGIwZS1lNGZmLTQzZmQtYTdiYS1kYTc3YTE3YzM2MzYifQ.Jm29jPliRvrK6Os34nSK3rhzIYLFjE__zdVGNng3uGKXGKzP3We_i6NPnhA0szJXMOKglXzUF1UgSz8MctbaxFS8XDusQPVe4LkB_45hwBm6TmBxzui911nt-1RbBLN_jZIlvl2lPrbTUH5hSn9kEkph6seWanTNQpz9tNEoVa6R_OX3kpJqxe8tLQUWw453A1JTwFNhdHa6-f1K8_Q_eEZ_4gOYINQ9t_fhTibdbkXZkJQFLop-Jwoybi9s4nwQU_dATocgcufq5eCeNItQeleT-23lGxIz0X7CiJrJynYLdd-ER0F77SumqEb5iCxhxuf4H7dovwd1kAmyKzLxpw&Version=2011-06-15
 ```
diff --git a/docs/sts/ldap.md b/docs/sts/ldap.md
index f28a3aa0e..94ace6037 100644
--- a/docs/sts/ldap.md
+++ b/docs/sts/ldap.md
@@ -14,7 +14,7 @@
     - [Policy](#policy)
     - [Response Elements](#response-elements)
     - [Errors](#errors)
-- [Sample Request](#sample-request)
+- [Sample `POST` Request](#sample-post-request)
 - [Sample Response](#sample-response)
 - [Testing](#testing)
 
@@ -189,7 +189,7 @@ XML response for this API is similar to [AWS STS AssumeRoleWithWebIdentity](http
 ### Errors
 XML error response for this API is similar to [AWS STS AssumeRoleWithWebIdentity](https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRoleWithWebIdentity.html#API_AssumeRoleWithWebIdentity_Errors)
 
-## Sample Request
+## Sample `POST` Request
 ```
 http://minio.cluster:9000?Action=AssumeRoleWithLDAPIdentity&LDAPUsername=foouser&LDAPPassword=foouserpassword&Version=2011-06-15
 ```
diff --git a/docs/sts/web-identity.md b/docs/sts/web-identity.md
index 9e451e8e1..e06f04f99 100644
--- a/docs/sts/web-identity.md
+++ b/docs/sts/web-identity.md
@@ -10,7 +10,7 @@
     - [Policy](#policy)
     - [Response Elements](#response-elements)
     - [Errors](#errors)
-- [Sample Request](#sample-request)
+- [Sample `POST` Request](#sample-post-request)
 - [Sample Response](#sample-response)
 - [Testing](#testing)
 - [Authorization Flow](#authorization-flow)
@@ -64,7 +64,7 @@ XML response for this API is similar to [AWS STS AssumeRoleWithWebIdentity](http
 ### Errors
 XML error response for this API is similar to [AWS STS AssumeRoleWithWebIdentity](https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRoleWithWebIdentity.html#API_AssumeRoleWithWebIdentity_Errors)
 
-## Sample Request
+## Sample `POST` Request
 ```
 http://minio.cluster:9000?Action=AssumeRoleWithWebIdentity&DurationSeconds=3600&WebIdentityToken=eyJ4NXQiOiJOVEF4Wm1NeE5ETXlaRGczTVRVMVpHTTBNekV6T0RKaFpXSTRORE5sWkRVMU9HRmtOakZpTVEiLCJraWQiOiJOVEF4Wm1NeE5ETXlaRGczTVRVMVpHTTBNekV6T0RKaFpXSTRORE5sWkRVMU9HRmtOakZpTVEiLCJhbGciOiJSUzI1NiJ9.eyJhdWQiOiJQb0VnWFA2dVZPNDVJc0VOUm5nRFhqNUF1NVlhIiwiYXpwIjoiUG9FZ1hQNnVWTzQ1SXNFTlJuZ0RYajVBdTVZYSIsImlzcyI6Imh0dHBzOlwvXC9sb2NhbGhvc3Q6OTQ0M1wvb2F1dGgyXC90b2tlbiIsImV4cCI6MTU0MTgwOTU4MiwiaWF0IjoxNTQxODA1OTgyLCJqdGkiOiI2Y2YyMGIwZS1lNGZmLTQzZmQtYTdiYS1kYTc3YTE3YzM2MzYifQ.Jm29jPliRvrK6Os34nSK3rhzIYLFjE__zdVGNng3uGKXGKzP3We_i6NPnhA0szJXMOKglXzUF1UgSz8MctbaxFS8XDusQPVe4LkB_45hwBm6TmBxzui911nt-1RbBLN_jZIlvl2lPrbTUH5hSn9kEkph6seWanTNQpz9tNEoVa6R_OX3kpJqxe8tLQUWw453A1JTwFNhdHa6-f1K8_Q_eEZ_4gOYINQ9t_fhTibdbkXZkJQFLop-Jwoybi9s4nwQU_dATocgcufq5eCeNItQeleT-23lGxIz0X7CiJrJynYLdd-ER0F77SumqEb5iCxhxuf4H7dovwd1kAmyKzLxpw&Version=2011-06-15
 ```
diff --git a/pkg/auth/credentials.go b/pkg/auth/credentials.go
index 231475232..06b2c8754 100644
--- a/pkg/auth/credentials.go
+++ b/pkg/auth/credentials.go
@@ -23,6 +23,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"strconv"
 	"strings"
 	"time"
 
@@ -136,25 +137,37 @@ func (cred Credentials) Equal(ccred Credentials) bool {
 
 var timeSentinel = time.Unix(0, 0).UTC()
 
-func expToInt64(expI interface{}) (expAt int64, err error) {
+// ErrInvalidDuration invalid token expiry
+var ErrInvalidDuration = errors.New("invalid token expiry")
+
+// ExpToInt64 - convert input interface value to int64.
+func ExpToInt64(expI interface{}) (expAt int64, err error) {
 	switch exp := expI.(type) {
+	case string:
+		expAt, err = strconv.ParseInt(exp, 10, 64)
 	case float64:
-		expAt = int64(exp)
+		expAt, err = int64(exp), nil
 	case int64:
-		expAt = exp
+		expAt, err = exp, nil
+	case int:
+		expAt, err = int64(exp), nil
+	case uint64:
+		expAt, err = int64(exp), nil
+	case uint:
+		expAt, err = int64(exp), nil
 	case json.Number:
 		expAt, err = exp.Int64()
-		if err != nil {
-			return 0, err
-		}
 	case time.Duration:
-		return time.Now().UTC().Add(exp).Unix(), nil
+		expAt, err = time.Now().UTC().Add(exp).Unix(), nil
 	case nil:
-		return 0, nil
+		expAt, err = 0, nil
 	default:
-		return 0, errors.New("invalid expiry value")
+		expAt, err = 0, ErrInvalidDuration
+	}
+	if expAt < 0 {
+		return 0, ErrInvalidDuration
 	}
-	return expAt, nil
+	return expAt, err
 }
 
 // GetNewCredentialsWithMetadata generates and returns new credential with expiry.
@@ -185,10 +198,11 @@ func GetNewCredentialsWithMetadata(m map[string]interface{}, tokenSecret string)
 	if err != nil {
 		return cred, err
 	}
-	cred.SecretKey = strings.Replace(string([]byte(base64.StdEncoding.EncodeToString(keyBytes))[:secretKeyMaxLen]), "/", "+", -1)
+	cred.SecretKey = strings.Replace(string([]byte(base64.StdEncoding.EncodeToString(keyBytes))[:secretKeyMaxLen]),
+		"/", "+", -1)
 	cred.Status = "on"
 
-	expiry, err := expToInt64(m["exp"])
+	expiry, err := ExpToInt64(m["exp"])
 	if err != nil {
 		return cred, err
 	}
diff --git a/pkg/auth/credentials_test.go b/pkg/auth/credentials_test.go
index fd2c0f91b..4577bef96 100644
--- a/pkg/auth/credentials_test.go
+++ b/pkg/auth/credentials_test.go
@@ -16,7 +16,43 @@
 
 package auth
 
-import "testing"
+import (
+	"encoding/json"
+	"testing"
+	"time"
+)
+
+func TestExpToInt64(t *testing.T) {
+	testCases := []struct {
+		exp             interface{}
+		expectedFailure bool
+	}{
+		{"", true},
+		{"-1", true},
+		{"1574812326", false},
+		{1574812326, false},
+		{int64(1574812326), false},
+		{int(1574812326), false},
+		{uint(1574812326), false},
+		{uint64(1574812326), false},
+		{json.Number("1574812326"), false},
+		{1574812326.000, false},
+		{time.Duration(3) * time.Minute, false},
+	}
+
+	for _, testCase := range testCases {
+		testCase := testCase
+		t.Run("", func(t *testing.T) {
+			_, err := ExpToInt64(testCase.exp)
+			if err != nil && !testCase.expectedFailure {
+				t.Errorf("Expected success but got failure %s", err)
+			}
+			if err == nil && testCase.expectedFailure {
+				t.Error("Expected failure but got success")
+			}
+		})
+	}
+}
 
 func TestIsAccessKeyValid(t *testing.T) {
 	testCases := []struct {