diff --git a/cmdgen.c b/cmdgen.c
index d48b3166..12d34065 100644
--- a/cmdgen.c
+++ b/cmdgen.c
@@ -16,8 +16,36 @@
 #include "sshkeygen.h"
 #include "mpint.h"
 
-FILE *progress_fp = NULL;
+static FILE *progress_fp = NULL;
+static bool linear_progress_phase;
+static unsigned last_progress_col;
 
+static ProgressPhase cmdgen_progress_add_linear(
+    ProgressReceiver *prog, double c)
+{
+    ProgressPhase ph = { .n = 0 };
+    return ph;
+}
+
+static ProgressPhase cmdgen_progress_add_probabilistic(
+    ProgressReceiver *prog, double c, double p)
+{
+    ProgressPhase ph = { .n = 1 };
+    return ph;
+}
+
+static void cmdgen_progress_start_phase(ProgressReceiver *prog,
+                                        ProgressPhase p)
+{
+    linear_progress_phase = (p.n == 0);
+    last_progress_col = 0;
+}
+static void cmdgen_progress_report(ProgressReceiver *prog, double p)
+{
+    unsigned new_col = p * 64 + 0.5;
+    for (; last_progress_col < new_col; last_progress_col++)
+        fputc('+', progress_fp);
+}
 static void cmdgen_progress_report_attempt(ProgressReceiver *prog)
 {
     if (progress_fp) {
@@ -27,6 +55,8 @@ static void cmdgen_progress_report_attempt(ProgressReceiver *prog)
 }
 static void cmdgen_progress_report_phase_complete(ProgressReceiver *prog)
 {
+    if (linear_progress_phase)
+        cmdgen_progress_report(prog, 1.0);
     if (progress_fp) {
         fputc('\n', progress_fp);
         fflush(progress_fp);
@@ -34,9 +64,11 @@ static void cmdgen_progress_report_phase_complete(ProgressReceiver *prog)
 }
 
 static const ProgressReceiverVtable cmdgen_progress_vt = {
-    null_progress_add_probabilistic,
+    cmdgen_progress_add_linear,
+    cmdgen_progress_add_probabilistic,
     null_progress_ready,
-    null_progress_start_phase,
+    cmdgen_progress_start_phase,
+    cmdgen_progress_report,
     cmdgen_progress_report_attempt,
     cmdgen_progress_report_phase_complete,
 };
diff --git a/sshkeygen.h b/sshkeygen.h
index f8f3159f..a965d3a6 100644
--- a/sshkeygen.h
+++ b/sshkeygen.h
@@ -180,15 +180,20 @@ struct ProgressReceiver {
 };
 
 struct ProgressReceiverVtable {
+    ProgressPhase (*add_linear)(ProgressReceiver *prog, double overall_cost);
     ProgressPhase (*add_probabilistic)(ProgressReceiver *prog,
                                        double cost_per_attempt,
                                        double attempt_probability);
     void (*ready)(ProgressReceiver *prog);
     void (*start_phase)(ProgressReceiver *prog, ProgressPhase phase);
+    void (*report)(ProgressReceiver *prog, double progress);
     void (*report_attempt)(ProgressReceiver *prog);
     void (*report_phase_complete)(ProgressReceiver *prog);
 };
 
+static inline ProgressPhase progress_add_linear(ProgressReceiver *prog,
+                                                double c)
+{ return prog->vt->add_linear(prog, c); }
 static inline ProgressPhase progress_add_probabilistic(ProgressReceiver *prog,
                                                        double c, double p)
 { return prog->vt->add_probabilistic(prog, c, p); }
@@ -197,15 +202,20 @@ static inline void progress_ready(ProgressReceiver *prog)
 static inline void progress_start_phase(
     ProgressReceiver *prog, ProgressPhase phase)
 { prog->vt->start_phase(prog, phase); }
+static inline void progress_report(ProgressReceiver *prog, double progress)
+{ prog->vt->report(prog, progress); }
 static inline void progress_report_attempt(ProgressReceiver *prog)
 { prog->vt->report_attempt(prog); }
 static inline void progress_report_phase_complete(ProgressReceiver *prog)
 { prog->vt->report_phase_complete(prog); }
 
+ProgressPhase null_progress_add_linear(
+    ProgressReceiver *prog, double c);
 ProgressPhase null_progress_add_probabilistic(
     ProgressReceiver *prog, double c, double p);
 void null_progress_ready(ProgressReceiver *prog);
 void null_progress_start_phase(ProgressReceiver *prog, ProgressPhase phase);
+void null_progress_report(ProgressReceiver *prog, double progress);
 void null_progress_report_attempt(ProgressReceiver *prog);
 void null_progress_report_phase_complete(ProgressReceiver *prog);
 extern const ProgressReceiverVtable null_progress_vt;
diff --git a/sshprime.c b/sshprime.c
index 0ee435e9..4431204c 100644
--- a/sshprime.c
+++ b/sshprime.c
@@ -114,19 +114,25 @@ const PrimeGenerationPolicy primegen_probabilistic = {
  * Reusable null implementation of the progress-reporting API.
  */
 
-ProgressPhase null_progress_add_probabilistic(
-    ProgressReceiver *prog, double c, double p) {
+static inline ProgressPhase null_progress_add(void) {
     ProgressPhase ph = { .n = 0 };
     return ph;
 }
+ProgressPhase null_progress_add_linear(
+    ProgressReceiver *prog, double c) { return null_progress_add(); }
+ProgressPhase null_progress_add_probabilistic(
+    ProgressReceiver *prog, double c, double p) { return null_progress_add(); }
 void null_progress_ready(ProgressReceiver *prog) {}
 void null_progress_start_phase(ProgressReceiver *prog, ProgressPhase phase) {}
+void null_progress_report(ProgressReceiver *prog, double progress) {}
 void null_progress_report_attempt(ProgressReceiver *prog) {}
 void null_progress_report_phase_complete(ProgressReceiver *prog) {}
 const ProgressReceiverVtable null_progress_vt = {
+    null_progress_add_linear,
     null_progress_add_probabilistic,
     null_progress_ready,
     null_progress_start_phase,
+    null_progress_report,
     null_progress_report_attempt,
     null_progress_report_phase_complete,
 };
diff --git a/windows/winpgen.c b/windows/winpgen.c
index 435500a6..dc901ccd 100644
--- a/windows/winpgen.c
+++ b/windows/winpgen.c
@@ -68,6 +68,7 @@ void nonfatal(const char *fmt, ...)
 
 struct progressphase {
     double startpoint, total;
+    /* For exponential phases */
     double exp_probability, exp_current_value;
 };
 
@@ -81,6 +82,19 @@ struct progress {
     ProgressReceiver rec;
 };
 
+static ProgressPhase win_progress_add_linear(
+    ProgressReceiver *prog, double overall_cost) {
+    struct progress *p = container_of(prog, struct progress, rec);
+
+    assert(p->nphases < MAXPHASE);
+    int phase = p->nphases++;
+
+    p->phases[phase].total = overall_cost;
+
+    ProgressPhase ph = { .n = phase };
+    return ph;
+}
+
 static ProgressPhase win_progress_add_probabilistic(
     ProgressReceiver *prog, double cost_per_attempt, double probability) {
     struct progress *p = container_of(prog, struct progress, rec);
@@ -133,6 +147,13 @@ static void win_progress_update(struct progress *p, double phasepos)
     SendMessage(p->progbar, PBM_SETPOS, (WPARAM)position, 0);
 }
 
+static void win_progress_report(ProgressReceiver *prog, double progress)
+{
+    struct progress *p = container_of(prog, struct progress, rec);
+
+    win_progress_update(p, progress);
+}
+
 static void win_progress_report_attempt(ProgressReceiver *prog)
 {
     struct progress *p = container_of(prog, struct progress, rec);
@@ -149,9 +170,11 @@ static void win_progress_report_phase_complete(ProgressReceiver *prog)
 }
 
 static const ProgressReceiverVtable win_progress_vt = {
+    win_progress_add_linear,
     win_progress_add_probabilistic,
     win_progress_ready,
     win_progress_start_phase,
+    win_progress_report,
     win_progress_report_attempt,
     win_progress_report_phase_complete,
 };