diff --git a/crypto/src/main/java/org/springframework/security/crypto/keygen/Base64StringKeyGenerator.java b/crypto/src/main/java/org/springframework/security/crypto/keygen/Base64StringKeyGenerator.java
index 347328bba04..9b28d68a723 100644
--- a/crypto/src/main/java/org/springframework/security/crypto/keygen/Base64StringKeyGenerator.java
+++ b/crypto/src/main/java/org/springframework/security/crypto/keygen/Base64StringKeyGenerator.java
@@ -68,7 +68,7 @@ public Base64StringKeyGenerator(Base64.Encoder encoder, int keyLength) {
 			throw new IllegalArgumentException("encode cannot be null");
 		}
 		if (keyLength < DEFAULT_KEY_LENGTH) {
-			throw new IllegalArgumentException("keyLength must be greater than or equal to" + DEFAULT_KEY_LENGTH);
+			throw new IllegalArgumentException("keyLength must be greater than or equal to " + DEFAULT_KEY_LENGTH);
 		}
 		this.encoder = encoder;
 		this.keyGenerator = KeyGenerators.secureRandom(keyLength);