diff --git a/include/psa/crypto.h b/include/psa/crypto.h
index 3036d17..fb9424a 100644
--- a/include/psa/crypto.h
+++ b/include/psa/crypto.h
@@ -1853,7 +1853,7 @@
  * \retval #PSA_ERROR_CORRUPTION_DETECTED
  */
 psa_status_t psa_cipher_generate_iv(psa_cipher_operation_t *operation,
-                                    unsigned char *iv,
+                                    uint8_t *iv,
                                     size_t iv_size,
                                     size_t *iv_length);
 
@@ -1888,7 +1888,7 @@
  * \retval #PSA_ERROR_CORRUPTION_DETECTED
  */
 psa_status_t psa_cipher_set_iv(psa_cipher_operation_t *operation,
-                               const unsigned char *iv,
+                               const uint8_t *iv,
                                size_t iv_length);
 
 /** Encrypt or decrypt a message fragment in an active cipher operation.
@@ -1926,7 +1926,7 @@
 psa_status_t psa_cipher_update(psa_cipher_operation_t *operation,
                                const uint8_t *input,
                                size_t input_length,
-                               unsigned char *output,
+                               uint8_t *output,
                                size_t output_size,
                                size_t *output_length);