1 files changed, 41 insertions, 0 deletions
diff --git a/src/main/scala/com/getbootstrap/savage/crypto/Pem.scala b/src/main/scala/com/getbootstrap/savage/crypto/Pem.scala
new file mode 100644
index 0000000..47496f1
--- /dev/null
+++ b/src/main/scala/com/getbootstrap/savage/crypto/Pem.scala
@@ -0,0 +1,41 @@
+package com.getbootstrap.savage.crypto
+
+import scala.util.{Try,Success,Failure}
+import java.io.StringReader
+import java.security.spec.X509EncodedKeySpec
+import org.bouncycastle.util.io.pem.PemReader
+import org.bouncycastle.util.io.pem.PemObject
+
+
+sealed class MalformedPemException(cause: Throwable) extends RuntimeException("The given data did not conform to the PEM format!", cause)
+
+sealed class UnexpectedPemDataTypeException(expectedType: String, pemObj: PemObject)
+  extends RuntimeException(s"PEM contained data of unexpected type! Expected: ${expectedType} Actual: ${pemObj.getType}")
+
+// PEM is the name for the format that involves "-----BEGIN PUBLIC KEY-----" etc.
+object Pem {
+  private val PublicKeyPemType = "PUBLIC KEY"
+
+  @throws[MalformedPemException]("if there is a problem decoding the PEM data")
+  private def decode(pem: String): PemObject = {
+    val pemReader = new PemReader(new StringReader(pem))
+    val pemObjTry = Try { pemReader.readPemObject() }
+    val closeTry = Try { pemReader.close() }
+    (pemObjTry, closeTry) match {
+      case (Failure(readExc), _) => throw new MalformedPemException(readExc)
+      case (_, Failure(closeExc)) => throw new MalformedPemException(closeExc)
+      case (Success(pemObj), Success(_)) => pemObj
+    }
+  }
+
+  // Decodes PKCS8 data in PEM format into a X509EncodedKeySpec
+  // which can be handled by sun.security.rsa.RSAKeyFactory
+  @throws[UnexpectedPemDataTypeException]("if the PEM contains non-public-key data")
+  def decodePublicKeyIntoSpec(publicKeyInPem: String): X509EncodedKeySpec = {
+    val pemObj = decode(publicKeyInPem)
+    pemObj.getType match {
+      case PublicKeyPemType => new X509EncodedKeySpec(pemObj.getContent)
+      case unexpectedType => throw new UnexpectedPemDataTypeException(PublicKeyPemType, pemObj)
+    }
+  }
+}