diff --git a/internal/crypto/nearby_base.h b/internal/crypto/nearby_base.h
index f47bf75d..23123150 100644
--- a/internal/crypto/nearby_base.h
+++ b/internal/crypto/nearby_base.h
@@ -19,6 +19,7 @@
 #ifndef THIRD_PARTY_NEARBY_INTERNAL_CRYPTO_NEARBY_BASE_H_
 #define THIRD_PARTY_NEARBY_INTERNAL_CRYPTO_NEARBY_BASE_H_
 
+#include <cstdint>
 #include <cstddef>
 #include <limits>
 #include <string>
diff --git a/internal/crypto/random.h b/internal/crypto/random.h
index 4b70063e..1daacb71 100644
--- a/internal/crypto/random.h
+++ b/internal/crypto/random.h
@@ -21,6 +21,7 @@
 
 #include <stddef.h>
 
+#include <cstdint>
 #include <string>
 
 #include "absl/types/span.h"
diff --git a/internal/crypto/sha2.h b/internal/crypto/sha2.h
index 30195717..bcf2bd61 100644
--- a/internal/crypto/sha2.h
+++ b/internal/crypto/sha2.h
@@ -17,6 +17,7 @@
 
 #include <stddef.h>
 
+#include <cstdint>
 #include <array>
 #include <string>