verify - Image Verification

Verify disc image integrity and compute cryptographic hashes

The verify command validates GameCube and Wii disc images and computes cryptographic hashes for verification and identification.

Usage

dolphin-tool verify [options]

Options

-i FILE, --input=FILE · string · required

Path to the disc image file to verify.

dolphin-tool verify -i game.iso

Supported formats:

• ISO/GCM
• GCZ
• WIA
• RVZ
• WBFS

-a ALGORITHM, --algorithm=ALGORITHM · string

Compute and print only the specified hash algorithm, then exit.

dolphin-tool verify -i game.iso -a sha1

Available algorithms:

• crc32 - CRC-32 checksum (fast)
• md5 - MD5 hash
• sha1 - SHA-1 hash (commonly used for disc verification)
• rchash - RetroAchievements hash (if compiled with RetroAchievements support)

If not specified, all default hashes are computed and a full report is generated.

-u USER, --user=USER · string

User folder path for temporary processing files.

dolphin-tool verify -i game.iso -u /tmp/dolphin

Will be automatically created if not set.

Output Formats

Full Report (No Algorithm Specified)

Without -a, verify outputs a comprehensive report:

dolphin-tool verify -i game.iso

Example output:

CRC32: 3a7d42f1
MD5: 6b5c8f9e2a3d1c4b7e8f9a0b1c2d3e4f
SHA1: a1b2c3d4e5f6g7h8i9j0k1l2m3n4o5p6q7r8s9t0
Problems Found: No

If problems are detected:

CRC32: 3a7d42f1
MD5: 6b5c8f9e2a3d1c4b7e8f9a0b1c2d3e4f
SHA1: a1b2c3d4e5f6g7h8i9j0k1l2m3n4o5p6q7r8s9t0
Problems Found: Yes

Severity: Medium
Summary: Invalid disc header

Severity: Low
Summary: Unexpected partition table

Single Hash Output (Algorithm Specified)

With -a, only the hash value is printed:

dolphin-tool verify -i game.iso -a sha1

Output:

a1b2c3d4e5f6g7h8i9j0k1l2m3n4o5p6q7r8s9t0

This format is suitable for scripting and automation.

Examples

Verify Image Integrity

Check for problems and compute all hashes:

dolphin-tool verify -i game.iso

Compute SHA-1 Hash Only

For Redump verification:

dolphin-tool verify -i game.iso -a sha1

Compute CRC32 Checksum

Fast checksum for quick verification:

dolphin-tool verify -i game.iso -a crc32

Compute MD5 Hash

dolphin-tool verify -i game.iso -a md5

Verify with Custom User Directory

dolphin-tool verify -i game.iso -u /tmp/dolphin-verify

Hash Algorithms

CRC32

Use case: Quick integrity checks, error detection

• Fast computation
• 32-bit checksum
• Good for detecting corruption
• Not cryptographically secure

dolphin-tool verify -i game.iso -a crc32

MD5

Use case: File identification, legacy compatibility

• 128-bit hash
• Widely supported
• Cryptographically broken (use SHA-1 instead)
• Still useful for non-security purposes

dolphin-tool verify -i game.iso -a md5

SHA-1

Use case: Disc verification, Redump database matching

• 160-bit hash
• Standard for disc image verification
• Used by Redump and other preservation databases
• Recommended for verification

dolphin-tool verify -i game.iso -a sha1

RetroAchievements Hash

Use case: RetroAchievements game identification

• Specific to RetroAchievements platform
• Only available if compiled with RetroAchievements support
• Used for achievement tracking

dolphin-tool verify -i game.iso -a rchash

Problem Detection

The verifier checks for various issues:

Severity Levels

• None - Informational only
• Low - Minor issues, game likely works
• Medium - Potential problems, may affect gameplay
• High - Serious issues, game may not work

Common Problems

• Invalid disc headers
• Corrupted partitions
• Missing or invalid encryption
• Partition table errors
• File system inconsistencies
• Hash mismatches (for signed content)

Verification Workflow

1. Verify After Download

# Download game
wget https://example.com/game.iso

# Verify integrity
dolphin-tool verify -i game.iso

# If problems found, re-download

2. Verify After Conversion

# Convert format
dolphin-tool convert -i game.iso -o game.rvz -f rvz -b 131072 -c zstd -l 5

# Verify converted image
dolphin-tool verify -i game.rvz

3. Compare with Known Hash

# Compute SHA-1
HASH=$(dolphin-tool verify -i game.iso -a sha1)

# Compare with expected value
EXPECTED="a1b2c3d4e5f6g7h8i9j0k1l2m3n4o5p6q7r8s9t0"

if [ "$HASH" = "$EXPECTED" ]; then
  echo "✓ Hash matches!"
else
  echo "✗ Hash mismatch!"
fi

Scripting Examples

Verify Multiple Files

#!/bin/bash

for file in *.iso; do
  echo "Verifying $file..."
  dolphin-tool verify -i "$file"
  echo "---"
done

Check Against Database

#!/bin/bash

# database.txt format: filename sha1
while IFS=' ' read -r filename expected_hash; do
  if [ -f "$filename" ]; then
    actual_hash=$(dolphin-tool verify -i "$filename" -a sha1)
    
    if [ "$actual_hash" = "$expected_hash" ]; then
      echo "✓ $filename"
    else
      echo "✗ $filename (hash mismatch)"
    fi
  else
    echo "- $filename (not found)"
  fi
done < database.txt

Generate Hash Database

#!/bin/bash

for iso in *.iso; do
  hash=$(dolphin-tool verify -i "$iso" -a sha1)
  echo "$iso $hash" >> hashes.txt
done

Parallel Verification

#!/bin/bash

find . -name "*.iso" -print0 | \
  xargs -0 -P 4 -I {} sh -c '
    echo "Verifying {}..."
    dolphin-tool verify -i "{}"
  '

Performance

Verification speed depends on:

• Storage speed - SSD much faster than HDD
• Image size - Larger files take longer
• Format - Compressed formats (RVZ, GCZ) slower than ISO
• Algorithm - CRC32 fastest, SHA-1 slower

Typical verification times on modern hardware:

Format	Size	CRC32	SHA-1	Full Report
ISO	4.3 GB	15s	25s	30s
RVZ	1.8 GB	30s	45s	60s
GCZ	2.1 GB	25s	40s	50s

Times are approximate

Exit Codes

• 0 - Success (verification completed)
• 1 - Failure (could not verify)

Note: Exit code 0 means verification completed, not that the image is valid. Check the output for problems.

Troubleshooting

”Unable to open input file”

Check:

• File exists and path is correct
• You have read permissions
• File is not corrupted or truncated

”No hash computed”

Occurs when:

• Algorithm is not supported
• Image format is invalid
• File is too corrupted to process

Slow Verification

To speed up:

• Use CRC32 instead of SHA-1 for quick checks
• Use SSD storage
• Verify ISO instead of compressed formats

Integration with Redump

Redump.org maintains verified disc image databases using SHA-1 hashes.

Verify Against Redump Database

1. Compute SHA-1 hash:

   dolphin-tool verify -i game.iso -a sha1
   

2. Search hash on Redump.org

3. Match confirms authentic dump

See Also

• Convert Command - Format conversion
• Header Command - Inspect metadata
• DolphinTool Overview - Other utilities