diff --git a/src/shared/tpm2-util.c b/src/shared/tpm2-util.c
index a26bf35c70..88cd7144b9 100644
--- a/src/shared/tpm2-util.c
+++ b/src/shared/tpm2-util.c
@@ -4239,6 +4239,18 @@ int tpm2_parse_luks2_json(
         return 0;
 }
 
+int tpm2_hash_alg_to_size(uint16_t alg) {
+        if (alg == TPM2_ALG_SHA1)
+                return 20;
+        if (alg == TPM2_ALG_SHA256)
+                return 32;
+        if (alg == TPM2_ALG_SHA384)
+                return 48;
+        if (alg == TPM2_ALG_SHA512)
+                return 64;
+        return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "Unknown hash algorithm id 0x%" PRIx16, alg);
+}
+
 const char *tpm2_hash_alg_to_string(uint16_t alg) {
         if (alg == TPM2_ALG_SHA1)
                 return "sha1";
diff --git a/src/shared/tpm2-util.h b/src/shared/tpm2-util.h
index 12f05b43f9..9ea8e5bda3 100644
--- a/src/shared/tpm2-util.h
+++ b/src/shared/tpm2-util.h
@@ -164,6 +164,8 @@ int tpm2_parse_luks2_json(JsonVariant *v, int *ret_keyslot, uint32_t *ret_hash_p
 #define TPM2_ALG_RSA 0x1
 #endif
 
+int tpm2_hash_alg_to_size(uint16_t alg);
+
 const char *tpm2_hash_alg_to_string(uint16_t alg);
 int tpm2_hash_alg_from_string(const char *alg);