diff --git a/proto/aes_cmac.proto b/proto/aes_cmac.proto
index b5dbd941..106bc117 100644
--- a/proto/aes_cmac.proto
+++ b/proto/aes_cmac.proto
@@ -29,7 +29,7 @@ message AesCmacParams {
 // key_type: type.googleapis.com/google.crypto.tink.AesCmacKey
 message AesCmacKey {
   uint32 version = 1;
-  bytes key_value = 2;  // Placeholder for ctype.
+  bytes key_value = 2;  // Placeholder for ctype and debug_redact.
   AesCmacParams params = 3;
 }
 
diff --git a/proto/aes_cmac_prf.proto b/proto/aes_cmac_prf.proto
index 94fe509d..c9942f30 100644
--- a/proto/aes_cmac_prf.proto
+++ b/proto/aes_cmac_prf.proto
@@ -25,7 +25,7 @@ option go_package = "github.com/tink-crypto/tink-go/v2/proto/aes_cmac_prf_go_pro
 // key_type: type.googleapis.com/google.crypto.tink.AesCmacPrfKey
 message AesCmacPrfKey {
   uint32 version = 1;
-  bytes key_value = 2;  // Placeholder for ctype.
+  bytes key_value = 2;  // Placeholder for ctype and debug_redact.
 }
 
 message AesCmacPrfKeyFormat {
diff --git a/proto/aes_ctr.proto b/proto/aes_ctr.proto
index 66c0ca1e..80880cb0 100644
--- a/proto/aes_ctr.proto
+++ b/proto/aes_ctr.proto
@@ -35,5 +35,5 @@ message AesCtrKeyFormat {
 message AesCtrKey {
   uint32 version = 1;
   AesCtrParams params = 2;
-  bytes key_value = 3;  // Placeholder for ctype.
+  bytes key_value = 3;  // Placeholder for ctype and debug_redact.
 }
diff --git a/proto/aes_ctr_hmac_streaming.proto b/proto/aes_ctr_hmac_streaming.proto
index 7927bde8..1725ee8c 100644
--- a/proto/aes_ctr_hmac_streaming.proto
+++ b/proto/aes_ctr_hmac_streaming.proto
@@ -42,5 +42,5 @@ message AesCtrHmacStreamingKeyFormat {
 message AesCtrHmacStreamingKey {
   uint32 version = 1;
   AesCtrHmacStreamingParams params = 2;
-  bytes key_value = 3;  // Placeholder for ctype.  // the main key, aka. "ikm", input key material
+  bytes key_value = 3 ;  // Placeholder for multi-line ctype and debug_redact.  // the main key, aka. "ikm", input key material
 }
diff --git a/proto/aes_eax.proto b/proto/aes_eax.proto
index e38b76b9..45a7eb10 100644
--- a/proto/aes_eax.proto
+++ b/proto/aes_eax.proto
@@ -37,5 +37,5 @@ message AesEaxKeyFormat {
 message AesEaxKey {
   uint32 version = 1;
   AesEaxParams params = 2;
-  bytes key_value = 3;  // Placeholder for ctype.
+  bytes key_value = 3;  // Placeholder for ctype and debug_redact.
 }
diff --git a/proto/aes_gcm.proto b/proto/aes_gcm.proto
index 3724b0a1..00ef9198 100644
--- a/proto/aes_gcm.proto
+++ b/proto/aes_gcm.proto
@@ -63,5 +63,5 @@ message AesGcmKeyFormat {
 
 message AesGcmKey {
   uint32 version = 1;
-  bytes key_value = 3;  // Placeholder for ctype.
+  bytes key_value = 3;  // Placeholder for ctype and debug_redact.
 }
diff --git a/proto/aes_gcm_hkdf_streaming.proto b/proto/aes_gcm_hkdf_streaming.proto
index c5e40236..1ecbc3d9 100644
--- a/proto/aes_gcm_hkdf_streaming.proto
+++ b/proto/aes_gcm_hkdf_streaming.proto
@@ -42,5 +42,5 @@ message AesGcmHkdfStreamingKeyFormat {
 message AesGcmHkdfStreamingKey {
   uint32 version = 1;
   AesGcmHkdfStreamingParams params = 2;
-  bytes key_value = 3;  // Placeholder for ctype.
+  bytes key_value = 3;  // Placeholder for ctype and debug_redact.
 }
diff --git a/proto/aes_gcm_siv.proto b/proto/aes_gcm_siv.proto
index fee87d76..50a64066 100644
--- a/proto/aes_gcm_siv.proto
+++ b/proto/aes_gcm_siv.proto
@@ -32,5 +32,5 @@ message AesGcmSivKeyFormat {
 // key_type: type.googleapis.com/google.crypto.tink.AesGcmSivKey
 message AesGcmSivKey {
   uint32 version = 1;
-  bytes key_value = 3;  // Placeholder for ctype.
+  bytes key_value = 3;  // Placeholder for ctype and debug_redact.
 }
diff --git a/proto/aes_siv.proto b/proto/aes_siv.proto
index 2c5e013e..3f9d83d0 100644
--- a/proto/aes_siv.proto
+++ b/proto/aes_siv.proto
@@ -40,5 +40,5 @@ message AesSivKeyFormat {
 message AesSivKey {
   uint32 version = 1;
   // First half is AES-CTR key, second is AES-SIV.
-  bytes key_value = 2;  // Placeholder for ctype.
+  bytes key_value = 2;  // Placeholder for ctype and debug_redact.
 }
diff --git a/proto/chacha20_poly1305.proto b/proto/chacha20_poly1305.proto
index 8f26821c..5dea2c4f 100644
--- a/proto/chacha20_poly1305.proto
+++ b/proto/chacha20_poly1305.proto
@@ -29,5 +29,5 @@ message ChaCha20Poly1305KeyFormat {}
 // at https://tools.ietf.org/html/rfc7539#section-2.8.
 message ChaCha20Poly1305Key {
   uint32 version = 1;
-  bytes key_value = 2;  // Placeholder for ctype.
+  bytes key_value = 2;  // Placeholder for ctype and debug_redact.
 }
diff --git a/proto/ecdsa.proto b/proto/ecdsa.proto
index e89783e8..36bfd48c 100644
--- a/proto/ecdsa.proto
+++ b/proto/ecdsa.proto
@@ -74,7 +74,7 @@ message EcdsaPrivateKey {
   EcdsaPublicKey public_key = 2;
   // Unsigned big integer in bigendian representation.
   // Required.
-  bytes key_value = 3;  // Placeholder for ctype.
+  bytes key_value = 3;  // Placeholder for ctype and debug_redact.
 }
 
 message EcdsaKeyFormat {
diff --git a/proto/ecies_aead_hkdf.proto b/proto/ecies_aead_hkdf.proto
index fa7eca5f..8997ad4c 100644
--- a/proto/ecies_aead_hkdf.proto
+++ b/proto/ecies_aead_hkdf.proto
@@ -105,7 +105,7 @@ message EciesAeadHkdfPrivateKey {
   EciesAeadHkdfPublicKey public_key = 2;
 
   // Required.
-  bytes key_value = 3;  // Placeholder for ctype.  // Big integer in bigendian representation.
+  bytes key_value = 3 ;  // Placeholder for multi-line ctype and debug_redact.  // Big integer in bigendian representation.
 }
 
 message EciesAeadHkdfKeyFormat {
diff --git a/proto/ed25519.proto b/proto/ed25519.proto
index 8d6234a9..564b4d07 100644
--- a/proto/ed25519.proto
+++ b/proto/ed25519.proto
@@ -46,7 +46,7 @@ message Ed25519PrivateKey {
   // The private key is 32 bytes of cryptographically secure random data.
   // See https://tools.ietf.org/html/rfc8032#section-5.1.5.
   // Required.
-  bytes key_value = 2;  // Placeholder for ctype.
+  bytes key_value = 2;  // Placeholder for ctype and debug_redact.
   // The corresponding public key.
   Ed25519PublicKey public_key = 3;
 }
diff --git a/proto/hkdf_prf.proto b/proto/hkdf_prf.proto
index 3b98d06e..2a151e7a 100644
--- a/proto/hkdf_prf.proto
+++ b/proto/hkdf_prf.proto
@@ -38,7 +38,7 @@ message HkdfPrfParams {
 message HkdfPrfKey {
   uint32 version = 1;
   HkdfPrfParams params = 2;
-  bytes key_value = 3;  // Placeholder for ctype.
+  bytes key_value = 3;  // Placeholder for ctype and debug_redact.
 }
 
 message HkdfPrfKeyFormat {
diff --git a/proto/hmac.proto b/proto/hmac.proto
index bd268f09..1a364146 100644
--- a/proto/hmac.proto
+++ b/proto/hmac.proto
@@ -33,7 +33,7 @@ message HmacParams {
 message HmacKey {
   uint32 version = 1;
   HmacParams params = 2;
-  bytes key_value = 3;  // Placeholder for ctype.
+  bytes key_value = 3;  // Placeholder for ctype and debug_redact.
 }
 
 message HmacKeyFormat {
diff --git a/proto/hmac_prf.proto b/proto/hmac_prf.proto
index 159d3db5..47adc39c 100644
--- a/proto/hmac_prf.proto
+++ b/proto/hmac_prf.proto
@@ -32,7 +32,7 @@ message HmacPrfParams {
 message HmacPrfKey {
   uint32 version = 1;
   HmacPrfParams params = 2;
-  bytes key_value = 3;  // Placeholder for ctype.
+  bytes key_value = 3;  // Placeholder for ctype and debug_redact.
 }
 
 message HmacPrfKeyFormat {
diff --git a/proto/hpke.proto b/proto/hpke.proto
index 9c428e31..d4e516dd 100644
--- a/proto/hpke.proto
+++ b/proto/hpke.proto
@@ -63,7 +63,7 @@ message HpkePrivateKey {
   HpkePublicKey public_key = 2;
   // KEM-encoding of private key (i.e., SerializePrivateKey() ) as described in
   // https://www.rfc-editor.org/rfc/rfc9180.html#name-cryptographic-dependencies.
-  bytes private_key = 3;
+  bytes private_key = 3;  // Placeholder for debug_redact.
 }
 
 message HpkeKeyFormat {
diff --git a/proto/jwt_ecdsa.proto b/proto/jwt_ecdsa.proto
index e8f1be24..c0326fdf 100644
--- a/proto/jwt_ecdsa.proto
+++ b/proto/jwt_ecdsa.proto
@@ -52,7 +52,7 @@ message JwtEcdsaPrivateKey {
   uint32 version = 1;
   JwtEcdsaPublicKey public_key = 2;
   // Unsigned big integer in bigendian representation.
-  bytes key_value = 3;  // Placeholder for ctype.
+  bytes key_value = 3;  // Placeholder for ctype and debug_redact.
 }
 
 message JwtEcdsaKeyFormat {
diff --git a/proto/jwt_hmac.proto b/proto/jwt_hmac.proto
index c6293230..496d5383 100644
--- a/proto/jwt_hmac.proto
+++ b/proto/jwt_hmac.proto
@@ -34,7 +34,7 @@ enum JwtHmacAlgorithm {
 message JwtHmacKey {
   uint32 version = 1;
   JwtHmacAlgorithm algorithm = 2;
-  bytes key_value = 3;  // Placeholder for ctype.
+  bytes key_value = 3;  // Placeholder for ctype and debug_redact.
 
   // Optional, custom kid header value to be used with "RAW" keys.
   // "TINK" keys with this value set will be rejected.
diff --git a/proto/tink.proto b/proto/tink.proto
index a5a5e509..abe37a25 100644
--- a/proto/tink.proto
+++ b/proto/tink.proto
@@ -116,7 +116,7 @@ message KeyData {
   string type_url = 1;  // In format type.googleapis.com/packagename.messagename
   // Required.
   // Contains specific serialized *Key proto
-  bytes value = 2;  // Placeholder for ctype.
+  bytes value = 2;  // Placeholder for ctype and debug_redact.
   enum KeyMaterialType {
     UNKNOWN_KEYMATERIAL = 0;
     SYMMETRIC = 1;
diff --git a/proto/xchacha20_poly1305.proto b/proto/xchacha20_poly1305.proto
index d080b779..f102d3fb 100644
--- a/proto/xchacha20_poly1305.proto
+++ b/proto/xchacha20_poly1305.proto
@@ -29,5 +29,5 @@ message XChaCha20Poly1305KeyFormat {
 // key_type: type.googleapis.com/google.crypto.tink.XChaCha20Poly1305Key
 message XChaCha20Poly1305Key {
   uint32 version = 1;
-  bytes key_value = 3;  // Placeholder for ctype.
+  bytes key_value = 3;  // Placeholder for ctype and debug_redact.
 }