The security characteristics of both euro banknotes and coins are of the highest technical standard, aiming at combating counterfeiting. In addition to this, the European Commission, in collaboration with the ECB and the member states of the eurozone, closely monitors all aspects of counterfeiting of the common currency.
More details on the security characteristics of the euro may be found οn the website of the European Central Bank.
(http://www.ecb.europa.eu/euro/banknotes/security/html/index.en.html)
A summary of the main security features of euro banknotes and coins as listed on the aforementioned website is given here below.
Security featues of euro banknotes
The security features incorporated into the euro banknotes include the watermark, the security thread, the see–through number, the raised print and the shifting image on the hologram. Some of these security features are visible from both sides, when the note is held up to the light.
Security features of euro coins
Euro coins incorporate high-security machine-readable characteristics. Sophisticated bi-metal and sandwich technologies have been incorporated into the €1 and €2 coins. The material of the 10, 20 and 50 cent coins is a unique alloy (nordic gold), which is difficult to melt and is exclusively used for coins. Lettering around the edge of the €2 coin and the use of a unique metal composition for the 10, 20 and 50 cent coins protects them against counterfeiting.