Add a new pkg/crypto/keys, first cut

- provides three functions
     - GetRandomAlphaNumeric()
     - GetRandomAlphaNumericFull()
     - GetRandomBase64()
     - ValidAccessKey()

pkg/utils/crypto/keys/common.go

@@ -0,0 +1,10 @@
+package keys
+
+const (
+	MINIO_ACCESS_ID = 20
+	MINIO_SECRET_ID = 40
+)
+
+func isalnum(c byte) bool {
+	return '0' <= c && c <= '9' || 'A' <= c && c <= 'Z' || 'a' <= c && c <= 'z'
+}

pkg/utils/crypto/keys/keys.go

@@ -0,0 +1,62 @@
+package keys
+
+import (
+	"crypto/rand"
+)
+
+var alphaNumericTable = []byte("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ")
+var alphaNumericTableFull = []byte("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789")
+
+func GetRandomAlphaNumeric(size int) ([]byte, error) {
+	alpha := make([]byte, size)
+	_, err := rand.Read(alpha)
+	if err != nil {
+		return nil, err
+	}
+
+	for i := 0; i < size; i++ {
+		alpha[i] = alphaNumericTable[alpha[i]%byte(len(alphaNumericTable))]
+	}
+	return alpha, nil
+}
+
+func GetRandomAlphaNumericFull(size int) ([]byte, error) {
+	alphaFull := make([]byte, size)
+	_, err := rand.Read(alphaFull)
+	if err != nil {
+		return nil, err
+	}
+	for i := 0; i < size; i++ {
+		alphaFull[i] = alphaNumericTableFull[alphaFull[i]%byte(len(alphaNumericTableFull))]
+	}
+	return alphaFull, nil
+}
+
+func GetRandomBase64(size int) ([]byte, error) {
+	rb := make([]byte, size)
+	n, err := rand.Read(rb)
+	if err != nil {
+		return nil, err
+	}
+	dest := make([]byte, n)
+	base64.URLEncoding.EncodeTo(dest, rb)
+	return dest, nil
+}
+
+func ValidateAccessKey(key []byte) bool {
+	for _, char := range key {
+		if isalnum(char) {
+			continue
+		}
+		switch char {
+		case '-':
+		case '.':
+		case '_':
+		case '~':
+			continue
+		default:
+			return false
+		}
+	}
+	return true
+}